DESC:FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)

Title: AN OPHTHALMIC COMPOSITION AND METHOD THEREOF

APPLICANT DETAILS:
(a) NAME: ENTOD PHARMACEUTICALS LTD.
(b) NATIONALITY: Indian
(c) ADDRESS: Ashirwad Building, Swami Vivekananda Rd, Opp. Badi Masjid,
Santosh Nagar, Bandra West, Mumbai, Maharashtra 400050

PREAMBLE TO THE DESCRIPTION:
The following specification (particularly) describes the nature of the invention (and the manner in which it is to be performed):

AN OPHTHALMIC COMPOSITION AND METHOD THEREOF

FIELD OF THE INVENTION:
The invention, in general, relates to the field of ocular solutions. More particularly, the present invention provides pilocarpine hydrochloride based ophthalmic composition for the treatment of presbyopia.

BACKGROUND OF THE INVENTION:
The following background discussion includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Presbyopia is an age-related decrease in visual acuity due to a decrease in the ability to focus on closely located objects, which is usually associated with a blurry view of objects at close distances. Presbyopia is usually associated with reduced accommodative ability of the eye. For example, the flexibility or elasticity of the lens and the strength of the ciliary muscle often decrease with age. A decrease in the flexibility or elasticity of the lens or the strength of the ciliary muscles may be due to a decrease in the ability of the eye to adjust the curvature of the lens to focus on objects at close distances, including objects within the normal reading distance.
Presbyopia typically starts affecting individuals over the age of 40. It is characterized by the loss of eye's ability to focus on close objects, leading to difficulties with tasks such as reading or using smartphones. The condition occurs due to the natural hardening of the lens inside the eye, making it less flexible and reducing its ability to change shape to focus on nearby objects.
Pilocarpine is derived from the leaves of the South American shrub Pilocarpus jaborandi.. It has a long history of use in ophthalmology, dating back to the late 19th and early 20th centuries. The drug works by mimicking the action of acetylcholine, a neurotransmitter in the parasympathetic nervous system. When applied topically as an ophthalmic solution, pilocarpine binds to muscarinic receptors on the iris sphincter muscle, causing it to contract. This contraction results in myosis, reducing the size of the pupil and subsequently improving the drainage of aqueous humour through the trabecular meshwork and Schlemm's canal.
Traditional pilocarpine formulations can cause significant side effects, such as eye irritation, redness, and systemic cholinergic effects. The absorption and bioavailability of pilocarpine is also a challenge and remains a factor to be improved.
There is a need of an effective composition which can effectively deliver pilocarpine to the target tissues, maximizing its therapeutic benefits while reducing systemic exposure and potential side effects. Hence, there is a need to provide an effective composition which minimizes the side effects, however enhances absorption and bioavailability of pilocarpine.
There is a further need for a non-invasive, on-demand treatment option that enhances near vision without the need for corrective lenses. Thus, the present invention provides a solution by changing the lives of millions with age-related blurred nearby objects. The present eye drops have the potential to replace reading glasses for people who have trouble seeing close-up as they age and improve close up- vision for 6 to 10hrs. The eye drops fall under the field of ophthalmology, focusing on the treatment and management of eye conditions, particularly presbyopia.

OBJECTIVE OF THE INVENTION:
The primary object of the present invention is to overcome the drawbacks associated with prior art.
Another object of the present invention is to provide Pilocarpine Hydrochloride Ophthalmic composition for the treatment of presbyopia.
Another object of the present invention is to provide eye drops based on Pilocarpine Hydrochloride.
Another object of the present invention is to provide an effective composition which can effectively deliver pilocarpine to the target tissues, maximizing its therapeutic benefits while reducing systemic exposure and potential side effects.
Another object of the present invention is to provide an effective composition which minimizes the side effects, however, enhances absorption and bioavailability of pilocarpine.
Another object of the present invention is to provide a method of preparation of the Pilocarpine Hydrochloride Ophthalmic composition, of the present invention.
Another object of the present invention is to provide a non-invasive, on-demand treatment option that enhances near vision without the need for corrective lenses.
Another object of the present invention is to provide a temperature-stable composition, that remains stable and effective over a broader range of temperature/s.

SUMMARY OF THE INVENTION:

The Invention provides a pilocarpine hydrochloride based ophthalmic composition for the treatment of presbyopia, comprising:
a) Pilocarpine HCl present in an amount of 1.25% w/v
b) Hydroxypropyl Methylcellulose present in an amount of 0.25% w/v
c) Boric acid present in an amount of 1.2% w/v
d) Borax present in an amount of 0.012% w/v
e) Disodium EDTA present in an amount of 0.01% w/v
f) Benzalkonium Chloride present in an amount of 0.0075 % w/v
g) Sodium Chloride present in an amount of 0.2% w/v
h) Glycerine present in an amount of 0.2% w/v
i) Sodium Hyaluronate present in an amount of 0.05% w/v
j) Water for Injection present in an amount of Q.S to 100 mL

The Invention provides a process of preparing the pilocarpine hydrochloride based ophthalmic composition for the treatment of presbyopia, comprising the steps of:
a) Preparing polymer Phase by using Hydroxypropyl methyl cellulose (HPMC) Solution, by adding Hydroxypropyl methyl cellulose to hot water under stirring for 20 minutes followed by autoclaving at 121°C- 30min; where said hot water is already at the temperature of 70°C -80°C; and after autoclaving, cooling the solution at room temperature with continuous stirring for 30 min to get clear solution;
b) Preparing buffer solution by taking 50% batch size of Water for injection in manufacturing vessel followed by adding and dissolving Di sodium EDTA, Boric acid, Borax and Benzalkonium chloride solution one by one with continuous stirring to get clear solution and adding in the solution of step (a);
c) Preparing the active component solution by taking 10% batch size of Water for injection (WFI) maintained at temperature of 30-40°C and dissolving Pilocarpine HCl under stirring to get clear solution, and mixing the resulting solution in the solution of step (b), to obtain the composition as claimed in claim 1.

DETAILED DESCRIPTION OF THE DRAWINGS:
To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting in their scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings in which:
Fig. 1: illustrate the mechanism of Action Pilocarpine has Dual MoA by activating muscarinic receptors located at the iris sphincter muscle and ciliary muscle of the present invention.

DETAILED DESCRIPTION:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
The present invention provides a composition of Pilocarpine hydrochloride, a cholinergic muscarinic agonist which activates muscarinic receptors located at smooth muscles such as the iris sphincter muscle and ciliary muscle.
The present invention offers a non-invasive alternative to reading glasses or contact lenses. It provides on-demand improvement in near vision without the need for corrective lenses, making it highly convenient for users.
In an embodiment, the present invention provides Pilocarpine Hydrochloride Ophthalmic Solution with strength of 1.25% w/v. The composition of the present invention comprises Pilocarpine Hydrochloride along with various other components which extends shelf life, increases bioavailability and minimizes ocular irritation.
In an embodiment, the composition comprises following components:
• Dynamic buffer system: The formulation includes a proprietary vehicle that enhances the absorption and bioavailability of pilocarpine in the ocular tissues. The dynamic buffer system which is help to adjusting pH to natural pH of the tear and that is optimizes the absorption and effectiveness of pilocarpine in the eye. This specific formulation enhances the delivery and consistency of the drug's action.
The dynamic buffer system contains stable buffering agent. Buffering agents such as boric acid and borax buffer can help maintain the desired pH and prevent degradation of product. The formulations require a pH within a specific range to maintain stability and activity.
• Excipients: These may include preservatives, lubricating agent, chelating agent, to ensure the solution's stability, sterility, and comfort upon administration.
• Preservatives: Eye drop formulations require preservatives to prevent microbial contamination during storage and use. Benzalkonium chloride preservatives are used in ophthalmic preparations. However, preservatives should be carefully selected to ensure compatibility with pilocarpine and minimize potential adverse effects on ocular tissues.
• Chelating agent: Chelating agents could inhibit microbial growth and assume a fundamental role in the antimicrobial therapeutic effect. Specific mechanisms and interactions apply in the exchange or retaining of iron between the chelating drugs with microbial microorganisms such as bacteria, fungi, and protozoa.
• Lubricating agent: This helps your tear film work more effectively to protect the surface of your eyes. You can get lubricating eye drops without a prescription
• Packaging material selection: Proposed packaging configuration of Pilocarpine Hydrochloride Ophthalmic Solution USP 1.25% w/v is white LDPE bottles.
In an embodiment, the composition comprises excipients like Benzalkonium chloride as an antimicrobial agent in an amount sufficient to meet or exceed the PET requirements of the Hydroxypropyl methyl cellulose (HPMC) as lubricating agent, Boric acid and Borax as buffering agent, di sodium EDTA as chelating agent. The composition also comprises other components, useful for improving the efficacy of the composition.
The composition is formulated with a dynamic buffer system which helps to adjust pH to natural pH of the tear and that optimizes the absorption and effectiveness of pilocarpine in the eye. The composition enhances the delivery and consistency of the drug's action.
In an embodiment, the concentration of 1.25% of pilocarpine is carefully selected to balance efficacy and minimize side effects, ensuring safety and comfort for patients or users.
The composition constricts the pupil, which increases the depth of focus. This allows the eye to better focus light on the retina, improving near vision. This mechanism specifically targets the visual challenges presented by presbyopia.
In an embodiment of the present invention, the Pilocarpine Hydrochloride Ophthalmic Solution is packaged in LDPE bottles with Nozzles and HDPE cap.
The Invention also provides a process of preparation of the composition.
In an embodiment, the process provided by the present invention comprises following steps:
• Step-1 is preparation of Polymer Phase by using Hydroxypropyl methyl cellulose (HPMC) Solution;
• Step-2 is Preparation of Dynamic buffer solution;
• Step-3 is Preparation of Active component solution;
• Step-4 is Preparation of Final bulk solution;
• Step -5 is Filtration and filling of solution in LDPE bottles.
In a specific embodiment, the process of preparing the composition comprises following steps:
Step-1: Preparation of Polymer Phase by using Hydroxypropyl methyl cellulose (HPMC) Solution
Take 15 to 25% batch size of Hot Water for injection (WFI) in manufacturing vessel and maintaining temperature of 70°C -80°C. Adding slowly Hydroxypropyl methyl cellulose under stirring for 15 to 25 minutes followed by autoclaving 115 to 125°C for 20 to 30min and thereafter cooling the solution at room temperature to get clear solution.
Step-2: Preparation of Dynamic Buffer system
Take required water for injection in manufacturing vessel followed by adding and dissolving Di sodium EDTA, Boric acid, Borax and Benzalkonium chloride solution, step wise with continuous stirring to get a clear solution.
Step-3: Preparation of Active component solution
Take 8 to 12% batch size of Water for injection (WFI) at temperature ranging from 30-40°C and dissolving Pilocarpine hydrochloride under stirring to get clear solution.
Step-4: Preparation of final bulk solution
Mixing the solution resulting from step-1, step-2 and step-3-under continuous stirring for 25 to 35 min to get clear solution. The pH of the resulting solution is maintained as 3.5 to 5.5.
Finally, making up the final volume of solution by using water for injection and stirring for 10 minutes, followed by filtering the solution by using 0.2 µ Nylon 66 Filter.
The filtered solution is filled in 10mL white LDPE bottles with nozzles and HDPE cap.
The composition comprises 1.25% w/v strength of pilocarpine. The 1.25% concentration of pilocarpine is optimized to balance efficacy in improving near vision while minimizing side effects.
The invention is further described with the help of non-limiting examples:
• Example 1:
Experimental findings to support pH Optimization
pH of the formulation is optimized to ensure stability and ocular site of installation. Drug product stability over this pH range is studied to mitigate the risk associated with change in pH between 3.5 to 5.5 this ranges, preferably pH 3.0 to 6.0 With the proposed following pH were evaluated for product stability.
- pH at Lower side at pH 3.00
- pH at middle side at pH 5.00
- pH at Higher side at pH 6.00
• Example 2:
Experimental findings to support Effect of Osmolarity Adjustment
Formulation osmolarity is adjusted to match the tear film osmolarity for improved ocular tolerance. Osmolarity range is studied in between 320 to 500 mOsm/kg, preferably 280 to 400 mOsm/kg.
• Example 3:
Experimental findings to support Effect of inert gas
Batches were compounded with and without nitrogen, to evaluate the effect of nitrogen on product CQA’s.
• Example 4:
Experimental findings to support Effect of Temperature (Autoclaving)
Batches were compounded with and without autoclaving to study the impact of autoclaving on drug product attributes.
• Example 5:
Experimental findings to support Compatibility study
Pre-formulation study was performed to evaluate the compatibility of product with materials which come in contact with the product during manufacturing. Compatibility study was carried out with S.S vessel, Silicon tubing’s, Nylon, PVDF and PES filters. Compatibility study results indicate that drug product was compatible with the product contact materials like. S.S vessel, Silicon tubing’s, Nylon, PVDF and PES filters.
• Example 6:
Experimental findings to support Photostability
Batches are compounded and subjected to ICH Photostability conditions. The drug product samples were placed in primary pack, secondary pack and as dark control samples (wrapped in aluminum foil).
• Example 7:
Experimental findings to support other studies to be performed
• Preservative efficacy studies (Benzalkonium chloride)
• Extractable and Leachable Study (Stability time point 3M, 6M)
• Sterility
• Example 8:
Experimental findings to support Clinical efficacy
Conducting phase I, II, and III clinical trials to evaluate the safety, efficacy, and tolerability of this invention in patients. Clinical trials demonstrated that product significantly improves near vision within 15 minutes of administration, with effects lasting up to 6 hours. The trials involved a large number of participants and used standard measures of near vision improvement to validate the efficacy of invention.
• Example 9:
Experimental findings to support Ocular Irritation Testing
Conducting ocular irritation studies to evaluate the safety and tolerability of the eye drop formulation. In vitro and In vivo Toxicity Testing: Assessing the cytotoxicity and acute/chronic toxicity of the formulation using cell culture and animal models.
The detailed experiments about the formulation study are mentioned below:
Formulation Development Study
• Example 10:

1) Selection of Buffer System:
When formulating Pilocarpine Ophthalmic Solution 1.25%, the choice of buffer system is critical for ensuring:
a) Drug stability (pilocarpine is prone to hydrolysis, especially at higher pH)
b) Ocular tolerability
c) Preservative effectiveness
d) Chemical compatibility with excipients and packaging

The following Ionic buffer is a proprietary buffering agent often based on Borate, Phosphate or Citrate buffers. Assume it's a mild buffer suitable for ophthalmic use and compatible with weakly acidic drugs.
Table 1: Selection of buffer system for Pilocarpine ophthalmic solution USP 1.25% w/v
Buffer System pKa Useful pH Range Justification
Citrate (Citric acid/sodium citrate) 3.1, 4.7, 5.4 3.0 – 6.2 Excellent for maintaining pH 4.5. Good buffer capacity. Non-toxic.
Phosphate (NaH2PO4/Na2HPO4) 2.1, 7.2 6.0 – 8.0 Poor for pilocarpine: promotes degradation above pH 6.
Borate (Borax/boric acid) 9.2 7.5 – 10.0 Common in ophthalmic preparations.
Has mild antimicrobial activity.
Good antimicrobial synergy with preservatives like benzalkonium chloride (BAK).

Phosphate buffer system
A trial batch of Pilocarpine Ophthalmic Solution USP 1.25% was prepared using a phosphate buffer system, consisting of sodium phosphate monobasic and sodium phosphate dibasic, to maintain the desired pH and provide buffering capacity. The detailed formulation composition is provided below table 2:

Table 2: Formulation composition and manufacturing procedure of Pilocarpine Ophthalmic Solution USP 1.25% with Phosphate buffer
Sr. No. Ingredients Qty (mg/mL) Qty % w/v Overages (%)
1 Pilocarpine HCl 13.75 1.25 10
2 Hydroxypropyl Methylcellulose 2.5 0.25 NA
3 Sodium Phosphate Monobasic 5 0.5 NA
4 Sodium Phosphate Dibasic 1 0.1 NA
5 Disodium EDTA 0.1 0.01 NA
6 Benzalkonium Chloride 0.0787 0.0075 5%
7 Sodium Chloride 2 0.2 —
8 Glycerine 2 0.2 —
9 Sodium Hyaluronate 0.5 0.05 —
10 Water for Injection Q.S to mL Q.S to 100 mL —
*Compensated for Assay (on anhydrous basis and Water content)
Manufacturing procedure
Step-1: Preparation of Polymer Phase by using Hydroxypropyl methyl cellulose (HPMC) Solution.
Take 20% batch size of Hot Water for injection (WFI) in manufacturing vessel and temperature 70°C -80°C. Add slowly Hydroxypropyl methyl cellulose under stirring for 20 minutes then autoclave 121°C- 30min. After autoclaving cool the solution at room temperature if necessary to add cool water with continuous stirring for 30 min to get clear solution. Clarity of solution pH
Clear -
Step-2: Preparation of Buffer solution.
Take 50% batch size of Water for injection in manufacturing vessel add and dissolve Di sodium EDTA, Sodium phosphate monobasic, Sodium phosphate dibasic and Benzalkonium chloride solution one by one with continuous stirring to get clear solution. Clear -
Step-3: Preparation of Active component solution.
Take 10% batch size of Water for injection (WFI) temperature 30-40°C ad and dissolve Pilocarpine HCl under stirring to get clear solution. Hazy -
Preparation of final bulk solution: Mixing the part-1 phase and Part II phase under stirring and Part-III solution under continuous stirring for 30 min to get clear solution. Check pH of solution pH 3.5 to 5.5) Hazy -
Make up the final volume of solution by using water for injection and stir for 5 min. Record the pH of solution. Hazy -
Filter the solution by using 2micron prefilter and final 0.2micron nylon 66 filter and filled in to LDPE bottles Hazy -

• Example 11:

Borate buffer system
A trial batch of Pilocarpine Ophthalmic Solution 1.25% was prepared using a borate buffer system, consisting of Boric acid and Borax, to maintain the desired pH and provide buffering capacity. The detailed formulation composition is provided below table 3:

Table 3: Formulation composition and manufacturing procedure of Pilocarpine Ophthalmic Solution USP 1.25% with borate buffer
Sr. No. Ingredients Qty (mg/mL) Qty % w/v Overages (%)
1 Pilocarpine HCl 13.75 1.25 10
2 Hydroxypropyl Methylcellulose 2.5 0.25 NA
3 Boric acid 12 1.2 NA
4 Borax 0.012 0.012 NA
5 Disodium EDTA 0.1 0.01 NA
6 Benzalkonium Chloride 0.0787 0.0075 5%
7 Sodium Chloride 2 0.2 -
8 Glycerine 2 0.2 -
9 Sodium Hyaluronate 0.5 0.05 -
10 Water for Injection Q.S to mL Q.S to 100 mL -
*Compensated for Assay (on anhydrous basis and Water content)
Manufacturing procedure
Step-1: Preparation of Polymer Phase by using Hydroxypropyl methyl cellulose (HPMC) Solution.
Take 20% batch size of Hot Water for injection (WFI) in manufacturing vessel and temperature 70°C -80°C. Add slowly Hydroxypropyl methyl cellulose under stirring for 20 minutes then autoclave 121°C- 30min. After autoclaving cool the solution at room temperature if necessary to add cool water with continuous stirring for 30 min to get clear solution. Clarity of solution pH
Clear -
Step-2: Preparation of Buffer solution.
Take 50% batch size of Water for injection in manufacturing vessel add and dissolve Di sodium EDTA, Boric acid, Borax and Benzalkonium chloride solution one by one with continuous stirring to get clear solution. Clear -
Step-3: Preparation of Active component solution.
Take 10% batch size of Water for injection (WFI) temperature 30-40°C ad and dissolve Pilocarpine HCl under stirring to get clear solution. Clear -
Preparation of final bulk solution: Mixing the part-1 phase and Part II phase under stirring and Part-III solution under continuous stirring for 30 min to get clear solution. Check pH of solution pH 3.5 to 5.5) Clear -
Make up the final volume of solution by using water for injection and stir for 5 min. Record the pH of solution. Clear -
Filter the solution by using 2micron prefilter and final 0.2micron nylon 66 filter and filled in to LDPE bottles Clear -

Example 12:

Citrate buffer system
A trial batch of Pilocarpine Ophthalmic Solution 1.25% was prepared using a Citrate buffer system, consisting of Citric acid and Sodium citrate dihydrate, to maintain the desired pH and provide buffering capacity. The detailed formulation composition is provided below table 4:

Table 4: Formulation composition and manufacturing procedure of Pilocarpine Ophthalmic Solution USP 1.25% with Citrate buffer
Sr. No. Ingredients Qty (mg/mL) Qty % w/v Overages (%)
1 Pilocarpine HCl 13.75 1.25 10
2 Hydroxypropyl Methylcellulose 2.5 0.25 NA
3 Citric acid 0.108 0.0108 NA
4 Sodium citrate dihydrate 0.58 0.058 NA
5 Disodium EDTA 0.1 0.01 NA
6 Benzalkonium Chloride 0.0787 0.0075 5%
7 Sodium Chloride 2 0.2 —
8 Glycerine 2 0.2 —
9 Sodium Hyaluronate 0.5 0.05 —
10 Water for Injection Q.S to mL Q.S to 100 mL —
*Compensated for Assay (on anhydrous basis and Water content)
Manufacturing procedure
Step-1: Preparation of Polymer Phase by using Hydroxypropyl methyl cellulose (HPMC) Solution.
Take 20% batch size of Hot Water for injection (WFI) in manufacturing vessel and temperature 70°C -80°C. Add slowly Hydroxypropyl methyl cellulose under stirring for 20 minutes then autoclave 121°C- 30min. After autoclaving cool the solution at room temperature if necessary to add cool water with continuous stirring for 30 min to get clear solution. Clarity of solution pH
Clear -
Step-2: Preparation of Buffer solution.
Take 50% batch size of Water for injection in manufacturing vessel add and dissolve Di sodium EDTA, Citric acid, sodium citrate dihydrate and Benzalkonium chloride solution one by one with continuous stirring to get clear solution. Clear -
Step-3: Preparation of Active component solution.
Take 10% batch size of Water for injection (WFI) temperature 30-40°C ad and dissolve Pilocarpine HCl under stirring to get clear solution. Hazy -
Preparation of final bulk solution: Mixing the part-1 phase and Part II phase under stirring and Part-III solution under continuous stirring for 30 min to get clear solution. Check pH of solution pH 3.5 to 5.5) Hazy -
Make up the final volume of solution by using water for injection and stir for 5 min. Record the pH of solution. Hazy -
Filter the solution by using 2micron prefilter and final 0.2micron nylon 66 filter and filled in to LDPE bottles Hazy -

Analytical results:
To compare the impact of buffer systems Borate, Citrate, and Phosphate on the initial stability and quality of Pilocarpine Ophthalmic Solution USP 1.25% w/v.

Table 5: Comparative analytical data of ionic buffer system
Test Parameters Citrate buffer Phosphate buffer Borate buffer
Condition Initial Initial Initial
Description Hazy solution Hazy solution Clear Colorless solution
Assay of Pilocarpine HCl (%) 108.86 112.49 109.32
pH 5.19 5 4.95
Related substances (%)
Isopilocarpine impurity A ND ND ND
Pilocarpinc impurity B ND ND ND
Isopilocarpine impurity ND ND ND
Any unspecified impurity ND ND ND
RRT- 1.7 0.12 0.12 ND
RRT-2.7 0.2 ND ND
RRT-2.9 ND 0.01 ND
RRT-3.7 0.08 0.15 ND
RRT-4.0 0.02 ND ND
RRT-5.6 0.12 0.13 ND
RRT-6.2 0.02 0.03 ND
RRT-11.4 0.01 0.02 ND
Total Impurity 0.57 0.44 ND

Observation based on the results from the above experiments:
Based on above buffer results, the borate buffer showed the most favorable results with a clear, Colorless appearance, assay within specification, and no detectable impurities, indicating excellent formulation stability.
Although citrate and phosphate buffers were acceptable in terms of pH and impurity limits, they exhibited haziness and minor unspecified impurities. Therefore, borate buffer is considered the most suitable choice for Pilocarpine Ophthalmic Solution 1.25% based on initial analytical data.

Example 13:

Effect of Autoclaved Study on Buffer System:
To assess the thermal stability and robustness of the buffer systems, each formulation was subjected to autoclaving (typically at 121?°C for 15–20 minutes). This study helps determine the impact of sterilization on the clarity, pH, assay, and impurity profile of Pilocarpine Ophthalmic Solution 1.25%.
Table 6: Comparative analytical data of ionic buffer system
Test Parameters Citrate buffer Phosphate buffer Borate buffer
Condition Initial Unautoclaved Initial autoclaved Initial Unautoclaved Initial autoclaved Initial Unautoclaved Initial autoclaved
Description Hazy solution Hazy solution Hazy solution Hazy solution Clear Colorless solution Clear Colorless solution
Assay of Pilocarpine HCl (%) 108.86 105.88 112.49 110.83 109.32 108.88
pH 5.19 5.23 5.00 4.85 4.95 4.89
Related substances (%)
Isopilocarpine impurity A ND ND ND ND ND ND
Pilocarpinc impurity B ND ND ND ND ND ND
Isopilocarpine impurity ND ND ND ND ND ND
Any unspecified impurity ND ND ND ND ND ND
RRT- 1.7 0.12 0.12 0.12 0.12 ND ND
RRT-2.7 0.2 0.12 ND ND ND ND
RRT-2.9 ND ND 0.01 0.01 ND ND
RRT-3.7 0.08 0.37 0.15 0.86 ND ND
RRT-4.0 0.02 0.01 ND ND ND ND
RRT-5.6 0.12 0.11 0.13 0.11 ND ND
RRT-6.2 0.02 0.02 0.03 0.02 ND ND
RRT-11.4 0.01 ND 0.02 ND ND ND
Total Impurity 0.57 0.75 0.44 1.12 ND ND

Observation based on the results from the above experiments:
Autoclaving impacted the citrate and especially the phosphate buffer systems, as seen by increased impurities and haziness. The phosphate buffer exceeded the total impurity post-autoclave (1.12%), indicating thermal degradation of Pilocarpine.
In contrast, the borate buffer system-maintained clarity, assay, pH, and showed no detectable impurities, confirming its superior thermal stability and compatibility with autoclave sterilization.

Example 14:

pH Optimization studies:
The pH of the formulation was optimized to ensure both the chemical stability of Pilocarpine HCl and ocular tolerability upon instillation. The objective was to evaluate the effect of varying pH on the overall stability profile of the drug product and to mitigate any potential risk due to pH fluctuations within the acceptable range.
The target pH range for evaluation was based on:
-The stability window of Pilocarpine HCl, known to be sensitive to hydrolysis outside a narrow pH range.
-Ocular compatibility, where pH values between 3.5 and 5.5 are generally well tolerated.
Accordingly, the following pH values were selected and formulations were evaluated:

a) pH 3.0
b) pH 4.0
c) pH 5.0
d) pH 6.0
Each batch was subjected to initial and accelerated stability testing

• Example 15:
Final Prototype Formulation and ICH Stability Study

Based on comparative evaluation of different buffer systems, the borate buffer system was finalized for the development of Pilocarpine Ophthalmic Solution 1.25% due to its superior Physical and chemical stability.

To establish the stability profile of the final formulation, an ICH stability study was conducted at the following storage conditions:
• 25?°C / 60% RH (Long-term)
• 30?°C / 65% RH (Intermediate)
• 40?°C / 75% RH (Accelerated)

Table 8: ICH stability data of Pilocarpine Ophthalmic Solution USP 1.25% w/v
Test Parameters Stability Condition
Initial 1-Month 3- month
25°C/60%RH 30°C/65%RH 40°C/75%RH 25°C/60%RH 30°C/65%RH 40°C/75%RH
Description Complies Complies Complies Complies Complies Complies Complies
Assay of Pilocarpine HCl (%) 102.19 102.34 102.32 102.33 102.28 102.29 102.32
Ph 5.07 4.79 4.70 4.7 3.87 3.83 3.80
Osmolality (mOsm/kg) 384 383 385 386 383 380 378
Related substances (%)
Isopilocarpine
impurity A ND ND ND ND ND ND ND
Pilocarpinc impurity B ND ND ND ND ND ND ND
Isopilocarpine impurity ND ND ND ND ND ND ND
Any unspecified impurity RRT-3.7 0.116 0.64 0.67 0.67 1.02 3.12 2.93
RRT-4.0 0.003 ND ND ND ND ND 0.02
RRT-4.7 0.007 ND ND ND ND ND 0.02
RRT-5.7 0.079 0.12 0.12 0.12 0.10 0.11 0.09
RRT-6.1 0.004 0.03 0.03 0.03 ND ND ND
RRT-6.4 0.012 ND ND ND ND ND ND
RRT-6.9 0.007 ND ND ND ND ND ND
RRT-12.3 0.02 0.02 0.02 0.02 0.01 0.01 0.02
Total Impurity 0.255 0..81 0.84 0.84 1.13 3.24 3.08

Observation based on the results from the above experiments:
Based on above data, The borate buffer formulation is physically and chemically stable under long-term and intermediate conditions up to 3 months.
Although the USP monograph does not list individual impurity specifications, the observed rise in unspecified impurities under accelerated conditions suggests potential degradation risk.
For regulatory compliance and product quality assurance, it is advisable to:
- Define in-house impurity limits based on ICH Q3B.
- Monitor RRT-3.7 impurity closely in long-term stability studies.

5. Preservative efficacy test: (Benzalkonium Chloride):
To determine the optimal concentration of Benzalkonium Chloride (BAK) required for the preservative efficacy and stability of the formulation, trial batches were manufactured with varying concentrations of BAK as follows:
• 80% of label claim
• 100% of label claim (standard concentration)
• 120% of label claim
The purpose of this study was to assess:
• Preservative effectiveness at each concentration,
• Any impact on drug product stability (assay, pH, and related substances),
• Ocular tolerability and clarity of the solution.
Each batch was evaluated under ICH stability conditions as well as preservative efficacy testing (PET) per USP <51>.

• Example 16:
Benzalkonium Chloride (BAK)-80% Concentration
As part of preservative optimization studies, a trial batch of Pilocarpine HCl Ophthalmic Solution was prepared using 80% of the label claim of Benzalkonium Chloride (BKC). The purpose of this study was to assess whether a reduced concentration of BKC would still meet required standards for Preservative efficacy (USP <51>), Physicochemical stability (assay, pH, impurities), and Physical properties (clarity, osmolality, compatibility).
Table 9: Formulation composition and manufacturing procedure of Pilocarpine Ophthalmic Solution USP 1.25% BKC- 80% concentration
Sr. No. Ingredients Qty (mg/mL) Qty % w/v Overages (%)
1 Pilocarpine HCl 13.75 1.25 10
2 Hydroxypropyl Methylcellulose 2.5 0.25 NA
3 Boric acid 12 1.2 NA
4 Borax 0.012 0.012 NA
5 Disodium EDTA 0.1 0.01 NA
6 Benzalkonium Chloride
(80)% conc.) 0.060 0.006 5%
7 Sodium Chloride 2 0.2 -
8 Glycerin 2 0.2 -
9 Sodium Hyaluronate 0.5 0.05 -
10 Water for Injection Q.S to mL Q.S to 100 mL -
*Compensated for Assay (on anhydrous basis and Water content)

Benzalkonium Chloride (BAK)-100% Concentration (Optimized concentration)
As part of preservative optimization studies, a trial batch of Pilocarpine HCl Ophthalmic Solution was prepared using 100% of the label claim of Benzalkonium Chloride (BKC). The purpose of this study was to assess whether a reduced concentration of BKC would still meet required standards for Preservative efficacy (USP <51>), Physicochemical stability (assay, pH, impurities), and Physical properties (clarity, osmolality, compatibility).
Table 10: Formulation composition and manufacturing procedure of Pilocarpine Ophthalmic Solution USP 1.25% BKC- 100% concentration
Sr. No. Ingredients Qty (mg/mL) Qty % w/v Overages (%)
1 Pilocarpine HCl 13.75 1.25 10
2 Hydroxypropyl Methylcellulose 2.5 0.25 NA
3 Boric acid 12 1.2 NA
4 Borax 0.012 0.012 NA
5 Disodium EDTA 0.1 0.01 NA
6 Benzalkonium Chloride
(100)% conc.) 0.075 0.0075 5%
7 Sodium Chloride 2 0.2 -
8 Glycerin 2 0.2 -
9 Sodium Hyaluronate 0.5 0.05 -
10 Water for Injection Q.S to mL Q.S to 100 mL -
*Compensated for Assay (on anhydrous basis and Water content)
Manufacturing procedure

• Example 17:

Benzalkonium Chloride (BAK)-120% Concentration (Optimized concentration)
As part of preservative optimization studies, a trial batch of Pilocarpine HCl Ophthalmic Solution was prepared using 120% of the label claim of Benzalkonium Chloride (BKC). The purpose of this study was to assess whether a reduced concentration of BKC would still meet required standards for Preservative efficacy (USP <51>), Physicochemical stability (assay, pH, impurities), and Physical properties (clarity, osmolality, compatibility).
Table 11: Formulation composition and manufacturing procedure of Pilocarpine Ophthalmic Solution USP 1.25% BKC- 100% concentration
Sr. No. Ingredients Qty (mg/mL) Qty % w/v Overages (%)
1 Pilocarpine HCl 13.75 1.25 10
2 Hydroxypropyl Methylcellulose 2.5 0.25 NA
3 Boric acid 12 1.2 NA
4 Borax 0.012 0.012 NA
5 Disodium EDTA 0.1 0.01 NA
6 Benzalkonium Chloride
(120)% conc.) 0.09 0.009 5%
7 Sodium Chloride 2 0.2 -
8 Glycerin 2 0.2 -
9 Sodium Hyaluronate 0.5 0.05 -
10 Water for Injection Q.S to mL Q.S to 100 mL -
*Compensated for Assay (on anhydrous basis and Water content)

In an embodiment of the present invention provide following functions:
• Extends the depth of focus. Pilocarpine contracts the iris sphincter muscle, constricting the pupil to improve near and intermediate visual acuity while maintaining some pupillary
• Increases the amplitude of accommodation. Pilocarpine also contracts the ciliary muscle and may shift the eye to a more myopic state.
In an embodiment, the present invention provides various advantages in following steps such as:
• Improving Near Vision Non-Invasively: Presbyopia typically requires the use of reading glasses or contact lenses, which can be inconvenient and uncomfortable for many users. The present invention provides a non-invasive, on-demand treatment option that enhances near vision without the need for corrective lenses.
• Temporary and Reversible Solution: Unlike surgical interventions, the current invention is offering a temporary and reversible method to improve near vision, allowing users to manage their presbyopia symptoms without permanent changes to their eyes.
• Quick Effectiveness: One of the technical challenges was ensuring that the pilocarpine solution works quickly enough to be practical for daily use. The present invention is demonstrating an onset of action within 15 minutes for 6 hrs. to provide near-immediate improvement in near vision, which is highly desirable for users.
• Sustained Effect: The solution needed to provide sustained improvement in near vision for a reasonable duration without requiring multiple applications throughout the day. The present invention is to achieve this with effects lasting up to 6 hours, offering significant convenience to users.
• Minimizing Common Side Effects: Traditional pilocarpine formulations can cause significant side effects, such as eye irritation, redness, and systemic cholinergic effects. The present formulation minimizes these side effects, making it more comfortable for users.
• User Compliance: By creating a well-tolerated solution with minimal side effects, formulation enhances user compliance. Patients are more likely to use the drops regularly if they do not experience discomfort or adverse effects.
Furthermore, the present eye drops have shown to improve close up- vision for 6 to 10hrs. The invention is significantly improving near and intermediate vision without compromising distance vision, quickly starts acting within 15 mins and effect lasts up to 6 hrs. and extends the effect up to 9 hrs. by instilling 2nd drops (after 3-6 hrs.). It reduces pupil size naturally by Dual Mechanism. The present invention uses a dynamic buffer technology which helps adjust pH to natural pH of the tear and negligible visual side effects.
The present invention offers significant advantages over traditional methods such as reading glasses or contact lenses, providing greater convenience and flexibility for patients.
,CLAIMS:WE CLAIM:
1. An ophthalmic composition for non invasive presbyopia management, comprising:
a) a therapeutically effective amount of pilocarpine hydrochloride present at 1.25% w/v;
b) a dynamic borate-based buffer system comprising boric acid and borax, arranged to maintain the composition pH within about 3.5 to 5.5; and
c) pharmaceutically acceptable excipients comprising Hydroxypropyl Methylcellulose (HPMC), disodium EDTA, benzalkonium chloride, sodium chloride, glycerine, and sodium hyaluronate.
2. The composition as claimed in claim 1, wherein Hydroxypropyl Methylcellulose (HPMC) is present at an amount of 0.25% w/v.
3. The composition as claimed in claim 1, wherein:
a) boric acid is present at an amount of 1.2% w/v;
b) borax is present at an amount of 0.012% w/v;
c) disodium EDTA is present at an amount of 0.01% w/v;
d) benzalkonium chloride is present at an amount of 0.0075% w/v;
e) sodium chloride is present at an amount of 0.2% w/v;
f) glycerine is present at an amount of 0.2% w/v;
g) sodium hyaluronate is present at an amount of 0.05% w/v.
4. The composition as claimed in claim 1, wherein the dynamic borate-based buffer system comprises boric acid and borax in amounts sufficient to adjust and maintain the composition pH within about 3.5 to 5.5.

5. A process of preparing the pilocarpine hydrochloride based ophthalmic composition for the treatment of presbyopia, comprising the steps of:

a) preparing a polymer phase by dissolving Hydroxypropyl Methylcellulose (HPMC) in water for injection heated to a temperature between about 70°C and 80°C, and then autoclaving the solution at about 121°C for approximately 30 minutes;
b) preparing a dynamic buffer phase by dissolving boric acid, borax, disodium EDTA, and benzalkonium chloride in water for injection under controlled temperature conditions;
c) preparing an active component phase by dissolving pilocarpine hydrochloride at 1.25% w/v in water for injection maintained at a temperature between about 30°C and 40°C;
d) sequentially combining the polymer phase with the dynamic buffer phase under continuous stirring, and subsequently adding the active component phase while continuing stirring for a period of about 25 to 35 minutes; and
e) subjecting the homogeneous mixture to sterile filtration using a 0.2 µm filter followed by aseptically filling the filtered solution into pre-sterilized low density polyethylene (LDPE) bottles.

6. The method as claimed in claim 5, wherein the dynamic buffer phase is prepared by first ensuring complete dissolution of boric acid and borax prior to the addition of disodium EDTA and benzalkonium chloride.
7. The method as claimed in claim 5, wherein after combining the phases, the stirring is continued for an additional period of about 10 minutes following the pH adjustment.