DESC:4. DESCRIPTION
Technical Field of the invention

The present invention relates to compositions comprising cetirizine solution for eye conditions. More particularly to cetirizine solution and its container and method of manufacturing the said composition and the container.

Background of the invention

The corneal epithelium, as the outermost layer of the cornea, serves as the primary defense against external threats following the tear film. Notably, the cornea boasts a high density of sensory nerve endings, making it the most densely innervated tissue in the body. These nerve endings originate from primary sensory neurons situated within the trigeminal ganglion (TG). These neurons extend axons that terminate delicately among the corneal epithelial cells, crucially facilitating the transmission of sensory information from the cornea. Furthermore, the innervation of the cornea plays a pivotal role in safeguarding and preserving the integrity of the ocular surface. Any form of aggression or inflammation affecting the ocular surface, particularly the cornea, triggers the activation of corneal sensory endings, generating nociceptive signals.

Ophthalmic conditions such as allergic conjunctivitis, rhinitis, rhino conjunctivitis is treated and cured by ophthalmic solutions. Conjunctivitis is characterized by itching, redness, swelling and lacrimation of the eye. Allergic conjunctivitis, whether acute or chronic, including conditions like vernal and atopic keratoconjunctivitis, is a prevalent eye ailment marked by discomfort and afflicting numerous individuals. A primary mode of treatment involves the use of topical medications, often administered for several months, or even extending to a year. Patients suffering from seasonal or perennial allergic conjunctivitis frequently rely on anti-allergic eye drops either for several months annually or on a continuous basis throughout the year. Ophthalmic solutions incorporate preservatives to extend the product's shelf life and to prevent contamination during the patient's treatment course. There are reservations regarding the long-term consequences of these eye drops. Literature has noted the adverse impacts of eye drops on ocular surfaces, with a consensus that the preservatives contained therein play a substantial role in these adverse effects. A significant portion of allergy patients experiences ocular surface disorders that can exacerbate ocular irritation and cellular damage when using ophthalmic solutions. These preservatives are recognized contributors to the toxicity of topical medications.

Specifically, Benzalkonium chloride (BKC) stands out as a major preservative component in eye drops, serving to guard against bacterial contamination in multi-dose bottles during the course of eye disease treatment. Certain studies have demonstrated that BKC leads to alterations in corneal nerve fibers in mice subjected to its application. Furthermore, studies employing BKC in corneal lesion models have shed light on morphological changes in cells and neurotoxic effects on the ocular surface. While these bactericidal agents are crucial for patient safety, given that multi-use containers for eye drops are often prone to misuse, concerns have been raised about the cytotoxic nature of BKC. This well-known irritant has the potential to harm the delicate ocular surface in countless patients who routinely use eye drops over many years, including those with conditions such as glaucoma, dry eye, or allergic conjunctivitis. BKC is also responsible for disrupting the preocular tear film, leading to adverse effects like dry eye, excessive tearing, burning sensations, and foreign body sensations. If patients cannot comfortably, safely, and conveniently use eye drops, treatment adherence is jeopardized, and treatment effectiveness substantially diminishes.

Currently available treatments comprise only a single active agent such as antihistamine or a mast cell stabilizer, typically provide relief only for acute allergic conjunctivitis and delayed phase inflammation and they do not address the signs and symptoms of the reaction.

The patent JP6893573B2 discloses an effective, stable, comfortable to administer in ophthalmology to treat allergic conjunctivitis ie, acute phase, delayed phase of inflammation or both), and allergic nasal conjunctivitis. A topical ophthalmic preparation containing an effective amount of cetirizine or a pharmaceutically acceptable salt thereof, cetirizine is the only active agent in the preparation, and 0.05% and 0.24% (w/v), and the formulation does not contain cyclodextrin and other solubilizing compounds.

Allergic eye conditions, such as allergic conjunctivitis, are a prevalent and often troublesome issue, causing symptoms like itching, redness, tearing, and general discomfort. The quest for relief from these symptoms has led to the creation of specialized eye drops that not only alleviate the immediate symptoms but also offer lasting comfort and protection for the eyes.
Preservative-free ophthalmic formulations have emerged as a significant advancement in the field of eye care. These innovative formulations offer a gentler, safer, and more comfortable solution for individuals with various eye conditions, such as dry eye syndrome, glaucoma, and allergies.

Benefits of Preservative-Free Ophthalmic Formulations:

1) Reduced Ocular Irritation: Preservative-free ophthalmic formulations are specifically designed to minimize irritation and discomfort. By eliminating harsh preservatives, patients can experience relief from burning, stinging, and redness associated with traditional eye drops.
2) Reduced Corneal Toxicity: Extended use of preservative-containing eye drops has been linked to corneal toxicity. Preservative-free formulations are gentler on the corneal surface, reducing the risk of damage and inflammation.
3) Improved Eye Comfort: Patients with sensitive eyes or those who need frequent application of eye drops, such as individuals with glaucoma, can benefit from the gentle nature of preservative-free formulations. These products reduce the likelihood of eye fatigue and discomfort associated with long-term use.
4) Lower Risk of Allergic Reactions: Allergic reactions to preservatives, such as BKC, are not uncommon. Preservative-free formulations significantly reduce the risk of allergic responses, making them suitable for a broader range of patients.
5) Enhanced Dry Eye Management: Preservative-free artificial tears are particularly beneficial for individuals suffering from chronic dry eye syndrome. These formulations provide immediate relief without the side effects associated with preservatives, helping maintain eye health and comfort.
However, there is a need to develop an anti-allergic (Cetirizine) formulation that is safe and such formulations for direct administration to the eye are more advantageous than systemic oral formulations and nasal sprays due to their rapid action and avoidance of side effects associated with systemic administration. In the ever-evolving landscape of ophthalmic care, innovation continues to shape the way we approach eye health and comfort. One such breakthrough is the development of preservative-free anti-allergic (Cetirizine) eye drops enriched with the soothing properties of Sodium Hyaluronate. These advanced formulations shall be useful for individuals who suffer from ocular allergies and discomfort. By combining the benefits of preservative-free solutions and the hydrating competence of sodium hyaluronate, this eye drop can provide a gentle yet highly effective remedy for those troubled by allergic reactions in their eyes.

Advantages of preservative-free cetirizine eye drops containing sodium hyaluronate Preservative-free cetirizine eye drops containing sodium hyaluronate offer several advantages for individuals experiencing ocular allergies and discomfort. These innovative eye drops provide a unique combination of antihistamine effects from cetirizine and the hydrating properties of sodium hyaluronate, resulting in a comprehensive solution for allergy-related eye symptoms. Here are the advantages of preservative-free cetirizine eye drops containing sodium hyaluronate:
1) Effective Allergy Relief: Cetirizine is an antihistamine that helps combat the histamine response responsible for allergic reactions. By including cetirizine in the eye drops, they effectively reduce itching, redness, tearing, and other allergy-related symptoms.
2) Preservative-Free Formulation: Preservatives, such as benzalkonium chloride (BKC), commonly found in many eye drops, can cause eye irritation and may be less suitable for individuals with sensitive eyes. Preservative-free cetirizine eye drops are a gentle alternative, reducing the risk of additional eye irritation or allergic reactions.
3) Long-Lasting Hydration: Sodium hyaluronate, a natural component of the eye, offers prolonged hydration and comfort. It forms a protective, moisturizing film on the ocular surface, helping to alleviate dryness and irritation often associated with allergies.
4) Reduction of Ocular Inflammation: Sodium hyaluronate has been shown to have anti-inflammatory properties, which can further aid in the management of inflammation resulting from allergic reactions.
5) Improved Tear Film Stability: The combination of cetirizine and sodium hyaluronate helps stabilize the tear film, preventing rapid tear evaporation and enhancing overall eye comfort.
6) Minimized Risk of Allergic Reactions: The absence of preservatives in these eye drops reduces the likelihood of allergic reactions, making them a safer choice for individuals who may be sensitive to preservatives.
7) Versatile Use: This eye drops can be used to manage a range of ocular allergies, including seasonal allergies, pet allergies, and indoor allergens. They offer relief for various allergic triggers.

The utilization of sodium hyaluronate in ophthalmic formulations represents a paradigm shift in ocular healthcare. Its biocompatibility, hydrating properties, and applications in dry eye management position it as a versatile and effective component in various formulations, including eye drops, ointments, and gels. The incorporation of sodium hyaluronate not only enhances the ocular health and comfort of patients but also extends to wound healing and post-surgical care, underscoring its pivotal role in the advancement of ophthalmic treatments. As research continues to unravel its potential, sodium hyaluronate's influence in ophthalmic formulations remains promising for the future of ocular health and therapy.

Preservative-free ophthalmic formulations have revolutionized the way we care for our eyes. They offer a gentle and effective solution for a variety of eye conditions, allowing patients to experience improved comfort and reduced ocular irritation. As more individuals become aware of the benefits of preservative-free eye care, the demand for such formulations continues to grow. Health care providers, ophthalmologists, and pharmaceutical companies are working together to ensure that patients have access to these innovative and safer alternatives. The future of eye care looks brighter with the widespread adoption of preservative-free ophthalmic formulations.

In summary, preservative-free cetirizine eye drops with sodium hyaluronate combine the advantages of antihistamine action and long-lasting hydration, providing effective relief from allergy-related eye symptoms while minimizing the risk of adverse reactions. These eye drops can greatly improve the comfort and well-being of individuals affected by ocular allergies.
The present invention implements a process of cetirizine formulation in a preservative free (two-piece) ophthalmic container as well as a preservative formulation in conventional three-piece ophthalmic container. One strategy includes Sodium Hyaluronate in the formulation that helps in lubricating and soothing effect to prevent further irritation or to relieve dryness of the eye. Another strategy has Hydroxypropyl methyl cellulose in the formulation which also enhances lubricating effect and comforts the eye. Also, the present invention relates to the manufacturing of the cetirizine formulation with or without preservatives.

Brief Summary of the invention

The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

The main objective of the present invention is to provide cetirizine solution in a preservative free container.
Another objective of the present invention is to process the cetirizine solution in a preservative free container.
Another objective of the present invention is to provide a cetirizine formulation containing Sodium Hyaluronate as a lubricating and hydrating polymer that further aids in inflammation management.
Another objective of the present invention is to provide a cetirizine formulation containing Hydroxypropyl methylcellulose as a lubricating polymer.
Another objective of the present invention is to process the cetirizine solution in a two-piece and/or three-piece ophthalmic container.
Further objects, features, and advantages of the invention will be readily apparent from the following description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

The invention will be further understood from the following detailed description of a preferred embodiment taken in conjunction with an appended drawing, in which:

Collect 120% of required quantity of Water for injection and purge nitrogen (100)

Transfer 30% of batch size Water for injection from step 1, into a separate container and heat to 45-55°C (101)

Add dispensed quantity of Sodium Hyaluronate under continuous stirring at 400 RPM for 15 minutes to get a clear viscous solution on cooling to room temperature (102)

Filter the solution through clarifying filter and store in a suitable container (103)

Transfer 50% of Water for injection into a separate container and cool to Room temperature (104)

add dispensed quantity of Benzalkonium chloride under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained (105)

add dispensed quantity of Cetirizine under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained (106)

add dispensed quantity of Glycerin under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained (107)

add dispensed quantity of Monobasic Sodium phosphate monohydrate under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained (108)

add dispensed quantity of Dibasic Sodium phosphate anhydrous under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained (109)

add dispensed quantity of Edetate sodium under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained (110)

add dispensed quantity of Polyethylene glycol 400 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained (111)

add dispensed quantity of Polysorbate 80 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained (112)

Transfer Phase I solution into Phase II solution and keep under stirring for proper mixing (113)

Check the pH of the solution and adjust the pH to 7.0 with Hydrochloric acid / Sodium Hydroxide solution under continuous stirring at 400 RPM (114)

Make up the volume to 100% of batch size with Water for Injection. Check the pH (115)

Filter the solution using sterile filter (0.22 micron) (116)

Fill 5 mL of sterilized solution in three-piece Ophthalmic containers followed by nozzeling, capping and labelling (117), according to an exemplary embodiment of the present invention;

Detailed Description of the invention

It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of component set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

The use of “including”, “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. Further, the use of terms “first”, “second”, and “third”, and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

The principles of operation, design configurations and evaluation values in these non-limiting examples can be varied and are merely cited to illustrate at least one embodiment of the invention, without limiting the scope thereof.
The embodiments disclosed herein can be expressed in different forms and should not be considered as limited to the listed embodiments in the disclosed invention. The various embodiments outlined in the subsequent sections are constructed such that it provides a complete and a thorough understanding of the disclosed invention, by clearly describing the scope of the invention, for those skilled in the art.
Throughout this specification various indications have been given as to preferred and alternative embodiments of the invention. It should be understood that it is the appended claims, including all equivalents that are intended to define the spirit and scope of this invention.
The present invention relates to compositions comprising cetirizine solution for eye conditions. More particularly to cetirizine solution and its container and method of manufacturing the said composition and the container. The present invention implements a process of cetirizine formulation in a preservative free (two-piece) ophthalmic container as well as a preservative formulation in a conventional (three-piece) ophthalmic container. The present invention also includes Sodium Hyaluronate or Hydroxypropyl methyl cellulose as a hydrating and lubricating polymer. Also, the present invention relates to the manufacturing of the cetirizine formulation with or without preservatives.

The following examples illustrate the present invention
Example 1
Example -1
S No. Ingredients Function Example - 1
% w/v
1 Cetirizine Active Pharmaceutical Ingredient 0.01 - 1
2 Glycerin Tonicity agent 0.1 - 6
3 Dibasic Sodium phosphate anhydrous Buffering agent 0.05 - 1.4
4 Polyethylene glycol 400 Viscosity agent 0.1 - 4.0
5 Polysorbate 80 Wetting agent 0.02 - 0.25
6 Hydroxypropyl methyl cellulose Viscosity agent 0.05 - 0.6
7 Hydrochloric acid pH adjusting agent Qs to pH
8 Sodium Hydroxide pH adjusting agent Qs to pH
9 Water for injection Vehicle Qs to 100% volume

Example 1 - Details of Manufacturing procedure
Step 1 Collect 120% of required quantity of Water for injection and purge nitrogen.
Phase I
Step 2 Transfer 30% of batch size Water for injection from step 1, into a separate container and heat to 65-75°C.
Step 3 Add dispensed quantity of Hydroxypropyl methyl cellulose under continuous stirring at 400 RPM for 15 minutes to get a dispersion, which later on turns to clear viscous solution on cooling to room temperature.
Step 4 Filter the solution through clarifying filter and store in a suitable container.
Phase II
Step 5 Transfer 50% of Water for injection into a separate container and cool to Room temperature.
Step 6 To step 5, add dispensed quantity of Dibasic Sodium phosphate under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 7 To step 6, add dispensed quantity of Sodium chloride under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 8 To step 7, add dispensed quantity of Cetirizine under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 9 To step 8, add dispensed quantity of Polyethylene glycol 400 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 10 To step 9, add dispensed quantity of Polysorbate 80 anhydrous under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 11 To step 10, add dispensed quantity of Glycerin under continuous stirring at 400 RPM for 20 minutes or till a clear solution is obtained.
Mixing of Phase I and Phase II
Step 12 Transfer Phase I solution into Phase II solution and keep under stirring for proper mixing at 500 RPM for 30 minutes.
Step 13 Check the pH of the solution and adjust the pH to 7.0 with Hydrochloric acid / Sodium Hydroxide solution under continuous stirring at 500 RPM.
Step 14 Make up the volume to 100% of batch size with Water for Injection. Check the pH.
Step 15 Filter the solution using sterile filter (0.22 micron).
Step 16 Fill 5 mL of sterilized solution in two-piece preservative free Ophthalmic containers followed by capping and labelling.

Test parameters Initial results Stability Results for Example-1
40°C± 2°C/NMT 25%RH 30°C± 2°C/65% ± 5%RH 25°C± 2°C/40% ± 5%RH
1 M 3 M 6 M 1 M 3 M 6 M 1 M 3 M 6 M
Description Clear, colourless aqueous solution
Identification Retention time of major peak of the sample solution corresponds to that of standard solution, as obtained in assay
pH 7.06 7.09 6.96 7.04 7.08 6.97 7.05 7.07 6.99 7.00
Osmolality (mOsm/kg) 297 301 311 315 300 303 301 304 306 305
Viscosity (cP) 5.43 5.63 5.90 5.56 5.52 5.76 5.30 5.69 5.68 5.67
Assay of Cetirizine (%) 101.2 101.7 101.5 103.1 101.2 100.0 101.2 101.3 100.0 101.5
Related Substances (%w/w)
Any unspecified degradation product 0.04 ND ND 0.01 ND ND 0.01 ND ND 0.01
Total degradation products 0.10 ND ND 0.01 ND ND 0.01 ND ND 0.01

ND: Not Detected

Example-2
S No. Ingredients Function % w/v
1 Cetirizine Active Pharmaceutical Ingredient 0.01 - 1
2 Benzalkonium chloride Preservative 0.001 - 0.2
3 Glycerin Tonicity agent 0.1 - 6.0
4 Monobasic Sodium phosphate monohydrate Buffering agent 0.02 - 1.3
5 Dibasic Sodium phosphate anhydrous Buffering agent 0.05 - 1.4
6 Disodium Edetate 2-hydrate Chelating agent 0.01 - 0.13
7 Polyethylene glycol 400 Viscosity agent 0.1 - 4.0
8 Polysorbate 80 Wetting agent 0.02 - 0.25
9 Hydroxypropyl methylcellulose Viscosity agent 0.05 - 0.6
10 Hydrochloric acid pH adjusting agent Qs to pH
11 Sodium Hydroxide pH adjusting agent Qs to pH
12 Water for injection Vehicle Qs to 100%

Step no. Example 2 - Details of Manufacturing procedure
Step 1 Collect 120% of required quantity of Water for injection and purge nitrogen.
Phase I
Step 2 Transfer 30% of batch size Water for injection from step 1, into a separate container and heat to 65-75°C.
Step 3 Add dispensed quantity of Hydroxypropyl methyl cellulose under continuous stirring at 400 RPM for 15 minutes to get a dispersion, which later turns to clear viscous solution on cooling to room temperature.
Step 4 Filter the solution through clarifying filter and store in a suitable container.
Phase II
Step 5 Transfer 50% of Water for injection into a separate container and cool to Room temperature.
Step 6 To step 5, add dispensed quantity of Benzalkonium chloride under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 7 To step 6, add dispensed quantity of Cetirizine under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 8 To step 7, add dispensed quantity of Glycerin under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 9 To step 8, add dispensed quantity of Monobasic Sodium phosphate monohydrate under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 10 To step 9, add dispensed quantity of Dibasic Sodium phosphate anhydrous under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 11 To step 10, add dispensed quantity of Disodium Edetate 2-hydrate under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 12 To step 11, add dispensed quantity of Polyethylene glycol 400 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 13 To step 12, add dispensed quantity of Polysorbate 80 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Mixing of Phase I and Phase II
Step 14 Transfer Phase I solution into Phase II solution and keep under stirring for proper mixing.
Step 15 Check the pH of the solution and adjust the pH to 7.0 with Hydrochloric acid / Sodium Hydroxide solution under continuous stirring at 400 RPM.
Step 16 Make up the volume to 100% of batch size with Water for Injection. Check the ph.
Step 17 Filter the solution using sterile filter (0.22 micron).
Step 18 Fill 5 mL of sterilized solution in three-piece Ophthalmic containers followed by nozzeling, capping and labelling.

Test parameters Initial results Stability Results for Example-2
40°C± 2°C/NMT 25%RH 30°C± 2°C/65% ± 5%RH 25°C± 2°C/40% ± 5%RH
1 M 3 M 6 M 1 M 3 M 6 M 1 M 3 M 6 M
Description Clear, colourless aqueous solution
Identification Retention time of major peak of the sample solution corresponds to that of standard solution, as obtained in assay
pH 7.07 7.04 6.98 7.02 7.03 7.00 7.02 7.05 7.02 7.00
Osmolality (mOsm/kg) 322 323 323 321 320 326 311 321 325 315
Viscosity (cP) 5.79 4.53 4.91 4.89 4.93 5.24 5.93 5.15 5.53 5.29
Assay (%) of
Cetirizine 100.2 99.7 100.9 100.6 100.7 100.1 100.0 100.1 99.7 101.0
Benzalkonium chloride 106.4 105.0 107.0 107.5 104.9 106.3 108.7 105.3 105.5 107.6
Disodium Edetate 2-hydrate 98.1 98.4 97.1 98.1 98.3 98.2 99.1 98.8 99.4 97.9
Related Substances (%w/w)
Any unspecified degradation product 0.03 0.03 0.07 0.04 0.01 0.02 0.05 0.03 0.02 0.04
Total degradation products 0.03 0.03 0.13 0.06 0.01 0.02 0.05 0.03 0.03 0.04

Example-3
S No. Ingredients Function % w/v
1 Cetirizine Active Pharmaceutical Ingredient 0.01 - 1
2 Glycerin Tonicity agent 0.1 - 6
3 Dibasic Sodium phosphate anhydrous Buffering agent 0.05 - 1.4
4 Polyethylene glycol 400 Viscosity agent 0.1 - 4.0
5 Polysorbate 80 Wetting agent 0.02 - 0.25
6 Sodium Chloride Tonicity agent 0.01 - 0.9
7 Sodium Hyaluronate Viscosity agent 0.05 - 0.5
8 Hydrochloric acid pH adjusting agent Qs to pH
9 Sodium Hydroxide pH adjusting agent Qs to pH
10 Water for injection Vehicle Qs to 100%

Step no. Example 3 - Details of Manufacturing procedure
Step 1 Collect 120% of required quantity of Water for injection and purge nitrogen.
Phase I
Step 2 Transfer 30% of batch size Water for injection from step 1, into a separate container and heat to 45-55°C.
Step 3 Add dispensed quantity of Sodium Hyaluronate under continuous stirring at 400 RPM for 15 minutes to get a clear viscous solution on cooling to room temperature.
Step 4 Filter the solution through clarifying filter and store in a suitable container.
Phase II
Step 5 Transfer 50% of Water for injection into a separate container and cool to Room temperature.
Step 6 To step 5, add dispensed quantity of Dibasic Sodium phosphate under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 7 To step 6, add dispensed quantity of Sodium chloride under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 8 To step 7, add dispensed quantity of Cetirizine under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 9 To step 8, add dispensed quantity of Polyethylene glycol 400 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 10 To step 9, add dispensed quantity of Polysorbate 80 anhydrous under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 11 To step 10, add dispensed quantity of Glycerin under continuous stirring at 400 RPM for 20 minutes or till a clear solution is obtained.
Mixing of Phase I and Phase II
Step 12 Transfer Phase I solution into Phase II solution and keep under stirring for proper mixing at 500 RPM for 30 minutes.
Step 13 Check the pH of the solution and adjust the pH to 7.0 with Hydrochloric acid / Sodium Hydroxide solution under continuous stirring at 500 RPM.
Step 14 Make up the volume to 100% of batch size with Water for Injection. Check the pH.
Step 15 Filter the solution using sterile filter (0.22 micron).
Step 16 Fill 5 mL of sterilized solution in two-piece preservative free Ophthalmic containers followed by capping and labelling.
Test parameters Initial results Stability Results for Example-3
40°C± 2°C/NMT 25%RH 30°C± 2°C/65% ± 5%RH 25°C± 2°C/40% ± 5%RH
1 M 3 M 6 M 1 M 3 M 6 M 1 M 3 M 6 M
Description Clear, colourless aqueous solution
Identification Retention time of major peak of the sample solution corresponds to that of standard solution, as obtained in assay
pH 6.97 7.01 7.08 6.99 7.09 7.11 7.01 7.03 7.10 7.05
Osmolality (mOsm/kg) 303 302 303 301 305 301 299 305 296 302
Viscosity (cP) 5.35 5.43 5.54 5.80 5.46 5.44 5.74 5.49 5.68 5.81
Assay of Cetirizine (%) 102.9 101.5 102.0 100.5 100.2 101.3 100.3 101.1 102.5 101.0
Related Substances (%w/w)
Any unspecified degradation product 0.04 0.02 0.03 0.04 0.02 0.03 0.02 0.01 0.03 0.03
Total degradation products 0.04 0.03 0.03 0.04 0.02 0.03 0.03 0.02 0.03 0.03

Example-4
S No. Ingredients Function % w/v
1 Cetirizine Active Pharmaceutical Ingredient 0.01 - 1
2 Benzalkonium chloride Preservative 0.001 - 0.2
3 Glycerin Tonicity agent 0.1 - 6.0
4 Monobasic Sodium phosphate monohydrate Buffering agent 0.02 - 1.3
5 Dibasic Sodium phosphate anhydrous Buffering agent 0.05 - 1.4
6 Disodium Edetate 2-hydrate Chelating agent 0.01 - 0.13
7 Polyethylene glycol 400 Viscosity agent 0.1 - 4.0
8 Polysorbate 80 Wetting agent 0.02 - 0.25
9 Sodium Hyaluronate Viscosity agent 0.05 - 0.5
10 Hydrochloric acid pH adjusting agent Qs to pH
11 Sodium Hydroxide pH adjusting agent Qs to pH
12 Water for injection Vehicle Qs to 100%

Step no. Example 4- Details of Manufacturing procedure
Step 1 Collect 120% of required quantity of Water for injection and purge nitrogen.
Phase I
Step 2 Transfer 30% of batch size Water for injection from step 1, into a separate container and heat to 45-55°C.
Step 3 Add dispensed quantity of Sodium Hyaluronate under continuous stirring at 400 RPM for 15 minutes to get a clear viscous solution on cooling to room temperature.
Step 4 Filter the solution through clarifying filter and store in a suitable container.
Phase II
Step 5 Transfer 50% of Water for injection into a separate container and cool to Room temperature.
Step 6 To step 5, add dispensed quantity of Benzalkonium chloride under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 7 To step 6, add dispensed quantity of Cetirizine under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 8 To step 7, add dispensed quantity of Glycerin under continuous stirring at 400 RPM for 15 minutes or till a clear solution is obtained.
Step 9 To step 8, add dispensed quantity of Monobasic Sodium phosphate monohydrate under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 10 To step 9, add dispensed quantity of Dibasic Sodium phosphate anhydrous under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 11 To step 10, add dispensed quantity of Disodium Edetate 2-hydrate under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 12 To step 11, add dispensed quantity of Polyethylene glycol 400 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Step 13 To step 12, add dispensed quantity of Polysorbate 80 under continuous stirring at 400 RPM for 5 minutes or till a clear solution is obtained.
Mixing of Phase I and Phase II
Step 14 Transfer Phase I solution into Phase II solution and keep under stirring for proper mixing.
Step 15 Check the pH of the solution and adjust the pH to 7.0 with Hydrochloric acid / Sodium Hydroxide solution under continuous stirring at 400 RPM.
Step 16 Make up the volume to 100% of batch size with Water for Injection. Check the pH.
Step 17 Filter the solution using sterile filter (0.22 micron).
Step 18 Fill 5 mL of sterilized solution in three-piece Ophthalmic containers followed by nozzeling, capping and labelling.

Test parameters Initial results Stability Results
Example-4
40°C± 2°C/NMT 25%RH 30°C± 2°C/65% ± 5%RH 25°C± 2°C/40% ± 5%RH
1 M 3 M 6 M 1 M 3 M 6 M 1 M 3 M 6 M
Description Clear, colourless aqueous solution
Identification Retention time of major peak of the sample solution corresponds to that of standard solution, as obtained in assay
pH 7.03 7.07 7.06 7.05 7.07 7.09 7.09 7.07 7.08 7.05
Osmolality (mOsm/kg) 321 323 323 321 324 322 323 324 323 320
Viscosity (cP) 4.40 4.35 4.88 4.49 4.44 4.30 4.69 4.56 4.26 4.49
Assay (%) of
Cetirizine 100.8 102.0 101.6 99.6 100.6 100.4 99.8 100.5 99.6 100.0
Benzalkonium chloride 95.9 97.5 97.4 99.1 96.9 95.1 97.9 95.0 95.5 98.9
Disodium Edetate 2-hydrate 99.0 97.4 96.0 97.6 98.0 97.1 98.6 98.0 98.2 98.7
Related Substances (%w/w)
Any unspecified degradation product 0.01 0.03 0.08 0.08 0.01 0.02 0.02 0.03 0.02 0.02
Total degradation products 0.01 0.07 0.09 0.08 0.02 0.03 0.03 0.04 0.04 0.02

COMPARATIVE EXAMPLES
S No. Ingredients % w/v
Example - 1 Example - 2 Example - 3 Example - 4
1 Cetirizine 0.01 - 1 0.01 - 1 0.01 - 1 0.01 - 1
2 Benzalkonium chloride - 0.001 - 0.2 - 0.001 - 0.2
3 Glycerin 0.1 - 6 0.1 - 6.0 0.1 - 6 0.1 - 6.0
4 Monobasic Sodium phosphate monohydrate - 0.02 - 1.3 - 0.02 - 1.3
5 Dibasic Sodium phosphate anhydrous 0.05 - 1.4 0.05 - 1.4 0.05 - 1.4 0.05 - 1.4
6 Disodium Edetate 2-hydrate - 0.01 - 0.13 - 0.01 - 0.13
7 Polyethylene glycol 400 0.1 - 4.0 0.1 - 4.0 0.1 - 4.0 0.1 - 4.0
8 Polysorbate 80 0.02 - 0.25 0.02 - 0.25 0.02 - 0.25 0.02 - 0.25
9 Sodium Chloride 0.01 - 0.9 - 0.01 - 0.9 -
10 Hydroxypropyl methylcellulose 0.05 - 0.6 0.05 - 0.6 - -
11 Sodium Hyaluronate - - 0.05 - 0.5 0.05 - 0.5
12 Hydrochloric acid Qs to pH Qs to pH Qs to pH Qs to pH
13 Sodium Hydroxide Qs to pH Qs to pH Qs to pH Qs to pH
14 Water for injection Qs to 100% Qs to 100% Qs to 100% Qs to 100%
The above example products are prepared in same way as mentioned earlier, removing the excipients wherever required.
Comparative results for Reference product (Zerviate) Vs Present Invention
Test parameters Reference product (Zerviate) Example-1 Example-2 Example-2 Example-4
Description Complies Complies Complies Complies Complies
Identification Complies Complies Complies Complies Complies
pH 7.04 7.06 7.07 6.97 7.03
Osmolality (mOsm/kg) 312 297 322 303 321.00
Viscosity (cP) 8.61 5.43 5.79 5.35 4.40
Assay (%) of
Cetirizine 100.00% 101.2% 100.2% 102.9% 100.80%
Benzalkonium chloride 106.40% - 106.4% - 95.90%
Disodium Edetate 2-hydrate 96.40% - 98.1% - 99.00%
Related Substances (%w/w)
Any unspecified degradation product 0.04% 0.04% 0.03% 0.04% 0.01%
Total degradation products 0.06% 0.10% 0.03% 0.04% 0.01%
Cytotoxicity or Biocompatibility In-Vitro
Ophthalmic solutions are formulated with preservatives to extend their product shelf life and prevent contamination during the course of patient treatment. One commonly used preservative is Benzalkonium chloride (BKC), However, concerns have been raised regarding the potential cytotoxicity of BKC. This compound is recognized as an irritant and, over time, may pose a risk to the delicate ocular surface in the millions of patients who rely on eye drops regularly, often for conditions such as glaucoma, dry eye, or allergic conjunctivitis. BKC's presence in these eye drops can lead to disruptions in the precorneal tear film, resulting in adverse effects like dry eye, excessive tearing, burning sensations, and feelings of foreign body discomfort. The ability of patients to use eye drops comfortably, safely, and conveniently is of paramount importance. Unless these criteria are met, treatment adherence cannot be guaranteed, ultimately compromising the effectiveness of the prescribed treatment.
Considering the above discussion, a series of formulations were prepared with/without preservatives along with the inclusion of Sodium Hyaluronate as a hydrating, lubricating and soothing polymer. And these formulations were tested for their in-vitro biocompatibility on corneal cell lines and in-vivo eye irritation testing on rabbits.
Example-5 (LNF-1) is a preservative composition for a Cetirizine ophthalmic solution that contains Sodium Hyaluronate as a polymer, while Example-6 (LNF-2) is a preservative-free composition for a cetirizine ophthalmic solution with Sodium Hyaluronate as a polymer unlike the Reference product (Zerviate) which contains Benzalkonium chloride (preservative) and Hydroxypropyl methylcellulose (polymer).
In this comparative toxicity evaluation, we investigated the effects of a reference product (Zerviate), an in-house cetirizine formulation (with preservative), and a preservative-free cetirizine formulation on corneal cell lines. Our study focused on assessing potential cytotoxicity and adverse impacts on corneal cell health. Through a series of in vitro experiments, we measured cell viability, oxidative stress and extracellular ATP release. By conducting comprehensive analyses and comparing the outcomes among these formulations, we aimed to provide valuable insights into the safety and suitability of our in-house preservative-free ophthalmic product for ocular use. The effect of sodium hyaluronate in the presence and absence of preservative is also evaluated in the current study.
S No. Ingredients Composition (% w/v)
LNF-1 (Example - 5) PLF-1 (Placebo of LNF-1) LNF-2 (Example - 6) PLF-1 (Placebo of LNF-2)
1 Cetirizine 0.24 - 0.24 -
2 Benzalkonium chloride 0.01 0.01 - -
3 Glycerin 1.6 1.6 1.6 1.6
4 Monobasic Sodium phosphate monohydrate 0.086 0.086 0.086 0.086
5 Dibasic Sodium phosphate anhydrous 0.21 0.21 0.21 0.21
6 Disodium Edetate 2-hydrate 0.025 0.025 - -
7 Polyethylene glycol 400 1.2 1.2 1.2 1.2
8 Polysorbate 80 0.09 0.09 0.09 0.09
9 Sodium Hyaluronate 0.1 0.1 0.1 0.1
10 Hydrochloric acid Qs to pH Qs to pH Qs to pH Qs to pH
11 Sodium Hydroxide Qs to pH Qs to pH Qs to pH Qs to pH
12 Water for injection Qs to 100% Qs to 100% Qs to 100% Qs to 100%

Cell Viability Score:
The rabbit corneal epithelial cell line was subcultured in T25 and 75 cm2 flasks, with 20,000 cells per well loaded onto a 96-well plate and incubated in a CO2 incubator overnight, reaching 90% confluence after 24 hours. The medium was then removed, and various formulations were added, including the RFP (Reference product (Zerviate)), LNF-1 (Example-5), LNF-2 (Example-6), PLF-1 (Placebo of LNF-1, without Cetirizine), and PLF-2 (Placebo of LNF-2, without Cetirizine), all in medium with 5% FBS. These were incubated for 4 hours and 24 hours.
4 hrs study % Cell viability
Control 100
LNF-1 110
LNF-2 125
PLF-1 115
PLF-2 136
RFP 94
After these incubation periods, MTT solution was added to each well, resulting in a yellow medium. The cells were then incubated for 30 minutes to 4 hours at 37°C, until intracellular purple formazan crystals became visible under a microscope. The MTT solution was removed, and a solubilizing solution (DMSO) was added, followed by incubation at room temperature or 37°C for 30 minutes to 2 hours, until the cells lysed, and the purple crystals dissolved. Table 1

The plate cover was removed, and the absorbance was measured using a microplate reader. The results were recorded and tabulated below. These results indicated that the composition LNF-2 (Example-6) demonstrated better compatibility both in the short-term (4 hours) and long-term (24 hours) when compared to LNF-1 (Example-5) and Reference product (Zerviate (0.24% Cetirizine
24 hrs study % Cell viability
Control 100
LNF-1 116
LNF-2 121
PLF-1 118
PLF-2 129
RFP 98
solution)). Table 2

The cell viability scores obtained in our study reveal a significant advantage of the preservative-free ophthalmic solution when compared to the preservative-containing ophthalmic formulation and Reference product. The preservative-free solution (PLF2 and LNF2) consistently yielded higher cell viability scores, indicating reduced cytotoxicity and cell damage. This finding is of particular importance in maintaining ocular health, as reduced cytotoxicity minimizes the risk of cell injury and supports the overall well-being of corneal cells. Healthy cell morphology in the preservative-free solution group further underscores its safety profile, suggesting a reduced potential for cellular stress and apoptosis. Also, the use of Sodium hyaluronate played a crucial role in maintaining the health of the ocular surface by maintaining a stable tear film that helped protect the cornea and conjunctiva, reducing the risk of irritation and damage. The higher cytotoxicity observed in the group treated with the preservative-containing formulations (RFP, PLF1 and LNF1) highlights a potential concern with such formulations. Altered cell morphology and reduced cell viability in this group indicate a more pronounced risk of cellular damage, emphasizing the significance of the study's findings in the context of ocular safety.
ROS Induction:
Reactive oxygen species (ROS) are chemically reactive molecules containing oxygen. They play important roles in various cellular processes and are involved in cell signaling, defense against pathogens, and regulation of cell growth. However, excessive ROS levels can lead to oxidative stress, causing cellular damage and contributing to various diseases.
The production of reactive oxygen species (ROS) is directly proportional to the level of hydrogen peroxide (H2O2) present in the sample. When quantifying ROS induction, the values were normalized relative to control cells under normal conditions, which were considered as having 100% cell viability. Exposure to Benzalkonium chloride (BKC) resulted in a significant increase in the generation of reactive oxygen species (ROS), as evidenced by the measurement of H2O2 production, which serves as a marker of oxidative stress. Notably, the 24-hour exposure of rabbit corneal epithelial cells to BKC had a substantial impact on cell protease activities, leading to a marked decrease in cell viability, as depicted in Tables 1 and 2.
Our study demonstrates that the preservative-free ophthalmic solution (PLF2 and LNF2) offers a substantial advantage in terms of ROS induction when applied to rabbit corneal cell lines. ROS, which can induce oxidative stress and contribute to cell damage, were significantly lower in cells treated with the preservative-free solution. This is a crucial discovery, as it suggests a reduced potential for oxidative stress and its associated cellular harm. Lower ROS levels in the preservative-free group highlight its safety, particularly for individuals with sensitive eyes or those requiring long-term ophthalmic therapy.
Conversely, the preservative-containing formulation (PLF1 and LNF1) along with the Reference product (RFP) resulted in a more considerable induction of ROS, signifying a heightened risk of oxidative stress and potential cell injury. This outcome underscores the importance of considering alternative, preservative-free formulations when balancing therapeutic efficacy and ocular safety.
Relative H2O2 production
Control 1
LNF-1 2.1
LNF-2 1.1
PLF-1 2.1
PLF-2 1.2
RFP 3.1

Extracellular ATP Release:
In our study, we examined the release of adenosine triphosphate (ATP), a crucial neurotransmitter involved in purinergic sensory signaling. Following a 24-hour recovery period, the culture supernatants from rabbit corneal epithelial cells were collected, subjected to filtration using 0.2µ PES syringe filters, and subsequently stored at -80°C to preserve the samples. The concentration of ATP in these supernatants was determined using the Luminescent Cell Viability Assay Kit, following the manufacturer's recommended protocol.
To quantify ATP levels, luminescence measurements were conducted using a Microplate reader. The intensity of the light signal generated was directly proportional to the amount of ATP present in the supernatant. The luminescence values obtained were then subjected to normalization. This involved two steps: first, the values were normalized relative to control cells maintained under standard conditions, which were considered to represent 100% cell viability. Secondly, the luminescence values were further normalized with respect to cell viability, providing a comprehensive assessment of ATP release in the context of the experiment.
Extracellular ATP release is a reliable marker of cellular damage and inflammation. The results of our study show that the preservative-free ophthalmic solution (PLF2 and LNF2) is associated with significantly lower extracellular ATP release in rabbit corneal cell lines.
In contrast, the preservative-containing formulation (PLF1 and LNF2) and Reference Product (RFP) triggered higher levels of extracellular ATP release, indicating an increased risk of inflammatory responses and cell damage. This outcome raises concerns about the potential for ocular irritation and discomfort associated with preservative-containing ophthalmic formulations.
Hence, this finding suggests a reduced risk of inflammation and cellular damage in the presence of the preservative-free solution. The diminished extracellular ATP levels in this group reflect a more favorable profile in terms of ocular health and safety.
Extracellular ATP Release
Control 1
LNF-1 1.9
LNF-2 1.1
PLF-1 2.3
PLF-2 1.2
RFP 2.9

In summary, considering the above in-vitro biocompatibility studies, our study demonstrates that the preservative-free ophthalmic solution with Sodium Hyaluronate as a hydrating and soothing polymer outperforms the preservative-containing formulation in several critical aspects related to ocular safety and corneal cell health. The preservative-free solution exhibits reduced cytotoxicity, lower ROS induction, and less extracellular ATP release, all of which are fundamental in maintaining ocular well-being and minimizing the risk of adverse effects. These findings have substantial clinical implications, highlighting the potential benefits of utilizing preservative-free ophthalmic solutions, especially for patients with sensitive eyes or those requiring long-term ophthalmic therapy. By prioritizing ocular safety and cell health, preservative-free formulations offer a promising alternative in balancing therapeutic efficacy and minimizing the risk of ocular irritation and inflammation.
In-Vivo Rabbit Eye Irritation Study
An eye irritation study is a crucial step in assessing the safety and tolerability of ophthalmic formulations. These results play a vital role in making informed decisions about the selection/usage of preservatives in eye care products, ultimately ensuring the safety and comfort of patients.
In the context of studying the impact of preservatives on the eye, an in-vivo rabbit eye irritation study was conducted. This study aimed to evaluate the potential of various formulations, including the RFP (Reference product), LNF-1 (Example-5), LNF-2 (Example-6), PLF-1 (Placebo of LNF-1, without Cetirizine), and PLF-2 (Placebo of LNF-2, without Cetirizine), to cause irritation in the eyes. All the In-House compositions (tested for eye irritation study) consisted of Sodium Hyaluronate as a hydrating and soothing polymer. The test followed the requirements of the OECD 405 guidelines for evaluating eye irritation from ophthalmic solutions.
One day prior to treatment, the eyes of each rabbit were examined for baseline parameters, including corneal opacity, area of opacity, iris, conjunctivae, and chemosis. A total of three rabbits were involved in the test, with each receiving a 0.1 mL dose of the test item in their right eye, while the untreated (left) eye served as the control. The appearance of each eye was immediately documented after administration. Observations were conducted at specific time points, including 1, 4, 24, 48, and 72 hours after administration, focusing on corneal opacity, area of opacity, iris, conjunctivae, and chemosis. Any reactions or signs of irritation in the eye were carefully noted and scored on a scale from 0 to 4. This comprehensive evaluation was conducted to assess the potential eye irritation caused by the test items, providing valuable insights into their safety and tolerability, particularly in comparison to the Reference product and placebos.
All animals appeared normal throughout the study. The results of scores for the rabbits appear in the below Table. The eyes of all animals appeared normal immediately following administration. The overall scoring for the test item is summarized below: Eye reactions? Corneal Opacity Lesions in Iris Conjunctival redness Chemosis
Batch code ? Exposure Hour ?
RFP (Reference product) Pre exposure 0 0 0 0
1 0 0 1 1
4 1 1 1 1
24 2 1 0 1
48 1 0 0 0
72 0 0 0 0

LNF1
(In-House preservative formula) Pre exposure 0 0 0 0
1 0 0 0 0
4 1 0 0 1
24 1 1 1 0
48 0 1 0 0
72 0 0 0 0

PLF1
(In-House Placebo of preservative formula) Pre exposure 0 0 0 0
1 0 0 1 1
4 1 0 1 1
24 2 1 0 0
48 1 1 0 0
72 0 0 0 0

LNF2
(In-House PRESERVATIVE FREE formula) Pre exposure 0 0 0 0
1 0 0 0 0
4 0 0 0 0
24 0 0 0 0
48 0 0 0 0
72 0 0 0 0

PLF2
(In-House Placebo of PRESERVATIVE FREE formula) Pre exposure 0 0 0 0
1 0 0 0 0
4 1 0 1 0
24 0 0 0 0
48 0 0 0 0
72 0 0 0 0

Control Pre exposure 0 0 0 0
1 0 0 0 0
4 0 0 0 0
24 0 0 0 0
48 0 0 0 0
72 0 0 0 0

Grading of Ocular Lesions
Observations Grading
Corneal Opacity
No ulceration or Opacity 0
Clear visibility of Iris 1
Details of the Iris slightly obscured 2
No details of the visibility of Iris 3
Opaque cornea 4

Iris
Normal 0
Marked deepened rugae, swelling, congestion or reactive to light 1
Haemorrhage, gross destruction, or no reaction to light 2

Conjunctivae (Redness related to palpebral and bulbar conjunctiva)
Normal 0
Some redness 1
Diffuse, crimson colour 2
Diffuse beefy red 3

Chemosis (Swelling of lids and/or nictitating membrane)
Normal 0
Some swelling above normal 1
Obvious swelling with partial eversion of lids 2
Swelling with lids about half closed 3

In this study comparing the eye irritation potential of a preservative-free ophthalmic solution to a preservative-containing ophthalmic formulation in rabbits, several key findings have emerged. The results of this study suggest that the preservative-free ophthalmic solution exhibits a notably lower or negligible degree of eye irritation compared to the preservative-containing formulation. Eye irritation scores were high for RFP (Reference product), PLF-1 and LNF-1 (Example-5) unlike with LNF-2, PLF-2 and Control. This could be attributed to the presence of Benzalkonium chloride (preservative) in the RFP (Reference product), LNF-1 and PLF-1
Rabbits treated with the preservative-containing ophthalmic formulations (RFP, PLF-1 and LNF-1) exhibited moderate to severe ocular irritation, including marked redness and swelling. Subjective discomfort was pronounced, and tear production showed a more significant reduction, suggesting that the preservatives in the formulation were associated with a higher degree of ocular irritation.
Conversely, the groups treated with the preservative-free ophthalmic formulations (PLF-2 and LNF-2) and Control displayed no signs of ocular irritation, such as redness, swelling, and discharge, throughout the observation period. Furthermore, subjective symptoms of discomfort, including stinging, burning, and itching, were significantly minimum in this group.
Preservative-free cetirizine eye drops provide prolonged relief and comfort for dry eyes without the need for preservatives that can lose their effectiveness over time. This is especially beneficial for those who require frequent or long-term use of eye drops. The inclusion of Sodium Hyaluronate is well-tolerated and poses a lower risk of causing allergic reactions compared to certain other ingredients found in eye drops. This quality makes it a suitable choice for individuals with sensitivities, potentially aiding in the preservation of the ocular surface's health and integrity. The reduced potential for irritation observed in PLF1 and LNF1, as opposed to RFP, can be attributed to the hydrating and soothing properties of Sodium Hyaluronate. A similar effect can be anticipated in the formulations PLF2 and LNF2 as well.
Overall, the study's results strongly support the conclusion that the preservative-free ophthalmic solution is a significantly more ocular-friendly option compared to the preservative-containing formulation. This finding is of clinical significance, particularly for individuals with sensitive eyes or those requiring long-term ophthalmic therapy, as it underscores the potential benefits of using preservative-free alternatives to minimize the risk of ocular irritation and discomfort.
,CLAIMS:5. CLAIMS
I/We Claim

1. A preservative free cetirizine solution comprising:
Cetirizine Active Pharmaceutical Ingredient 0.01 - 1 %w/w
Glycerin Tonicity agent 0.1 - 6.0 %w/w
Dibasic Sodium phosphate anhydrous Buffering agent 0.05 - 1.4 %w/w
Polyethylene glycol 400 Viscosity agent 0.1 - 4.0 %w/w
Polysorbate 80 Wetting agent 0.02 - 0.25 %w/w
Sodium Chloride Tonicity agent 0.01 - 0.9 %w/v
Sodium Hyaluronate or Hydroxypropyl methyl cellulose Viscosity agent0.05 - 0.6 %w/v
Hydrochloric acid pH adjusting agent Qs to pH
Sodium Hydroxide pH adjusting agent Qs to pH
Water for injection Vehicle Qs to 100% volume
2. A method of preparing cetirizine solution comprising of following steps:
collect 120% of required quantity of water for injection and purge nitrogen 100;
transfer 30% of batch size water for injection from step 1, into a separate container and heat to above 50°c 101;
add dispensed quantity of sodium hyaluronate or hydroxypropyl methyl cellulose under continuous stirring at 400 rpm for 15 minutes to get a clear viscous solution on cooling to room temperature 102;
filter the solution through clarifying filter and store in a suitable container 103;
transfer 50% of water for injection into a separate container and cool to room temperature 104;
add dispensed quantity of dibasic sodium phosphate anhydrous under continuous stirring at 400 rpm for 15 minutes or till a clear solution is obtained 105;
add dispensed quantity of sodium chloride under continuous stirring at 400 rpm for 15 minutes or till a clear solution is obtained 106;
add dispensed quantity of cetirizine under continuous stirring at 400 rpm for 5 minutes or till a clear solution is obtained 107;
add dispensed quantity of polyethylene glycol 400 under continuous stirring at 400 rpm for 5 minutes or till a clear solution is obtained 108;
add dispensed quantity of polysorbate 80 under continuous stirring at 400 rpm for 5 minutes or till a clear solution is obtained 109;
add dispensed quantity of glycerin under continuous stirring at 400 rpm for 20 minutes or till a clear solution is obtained 110;
transfer phase i solution into phase ii solution and keep under stirring for proper mixing at 400 rpm for 30 minutes 111;
check the ph of the solution and adjust the ph to 7.0 with hydrochloric acid / sodium hydroxide solution under continuous stirring at 400 rpm 112;
make up the volume to 100% of batch size with water for injection 113;
check the ph filter the solution using sterile filter (0.22 micron) 114;
fill 5 ml of sterilized solution in two-piece preservative free ophthalmic containers followed by capping and labelling 115;