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 this 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 Atropine Sulfate based ophthalmic composition for the treatment of myopia (near sightedness/ short sightedness).
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.
Myopia also known as near-sightedness and short-sightedness is an eye disease which is a refractive error that causes blurry distance vision. It is the most common cause of impaired vision in people under the age of 40. Myopia usually begins in childhood, but it can continue to worsen into early adulthood.
Myopia occurs when the eye focuses light rays in front of the retina, instead of on the retina. This makes distant objects look blurry. The study shows that in the year 2000, roughly 25% of the world's population was myopic. Research suggests that by the year 2050, roughly half the world’s population will be nearsighted. symptoms of myopia include eyestrain, headaches, squinting to see properly, and difficulty in seeing objects far away, such as road signs or a blackboard at school.
Myopia can be cured by using ophthalmic atropine sulfate composition. Atropine is the best-known member of a group of drugs known as muscarinic antagonists, which are competitive antagonists of acetylcholine at muscarinic receptors. This naturally occurring tertiary amine was first isolated from the Atropa belladonna plant by Mein in 1831 (Weiner, 1985). Atropine is also derived from plants of the Solanaceae family. Atropine has been used for centuries in various medicinal applications, including ophthalmology. It was originally used for its mydriatic (pupil-dilating) and cycloplegic (paralysis of the ciliary muscle) properties.
Atropine is long-acting, it is well absorbed (in the gastrointestinal tract (GIT), mucous membranes, and eyes) and distributed as it readily crosses the blood-brain barrier and the placenta. It has a bioavailability of 90% while 50% is bound in plasma with a plasma half-life of 2-5 hours. Its ocular effects last for days. Hepatic oxidation is responsible for its partial metabolism while about 30-50% is excreted unchanged in the urine.
Therefore, the Atropine Sulfate based ophthalmic composition can be used as its play a role in controlling the progression of myopia especially in children. Atropine is primarily known for its mydriatic (pupil-dilating) and cycloplegic (paralysis of the ciliary muscle) effects especially it relates to dynamic ionic buffer system.
Thus, there is a need for an Atropine Sulfate based ophthalmic composition stabilized with ionic buffer having antibacterial and antifungal properties for treating myopia ensuring optimal pH to avoid irritation and ensure proper drug stability and bioavailability. And, providing an ophthalmic composition with suitable ionic strength and osmolarity of the solution to match the isotonicity of the tear fluid to prevent any discomfort due to hypertonic or hypotonic solutions.
The Present invention provides a Atropine Sulfate based ophthalmic composition stabilized with buffer system which is ionic-buffered preservative that contains buffers, polyols, chelating agent, tonicity modifier and or viscosity enhancer. It functions as an oxidizing preservative with antibacterial and antifungal properties. The components quickly degrade upon contact with cations on the ocular surface resulting.
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 an Atropine Sulfate based ophthalmic composition for the treatment of myopia (near sightedness/ short sightedness).
Another object of the present invention is to provide an Atropine Sulfate Ophthalmic solution composition stabilized with ionic-buffer eye drop for treating myopia.
Another object of the present invention is to provide an Atropine Sulfate Ophthalmic solution composition stabilized with ionic-buffer eye drop for treating and controlling the progression of myopia myopia especially in children.
A primary objective of present invention is to provide an Atropine Sulfate Ophthalmic solution composition stabilized with ionic buffer system preventing the degradation of atropine in the solution.
Another object of the present invention is to provide an Atropine Sulfate Ophthalmic solution composition eye drop for all age group for effective treatment against myopia.
Another object of the present invention is to provide an Atropine Sulfate Ophthalmic solution composition eye drop inhibiting the growth of myopia in all age group especially in children.
Another object of the present invention is to provide an Atropine Sulfate based ophthalmic composition having antibacterial and antifungal properties for treating myopia.
Another object of the present invention is to provide an Atropine Sulfate based ophthalmic composition eye drop ensuring optimal pH to avoid irritation and ensure proper drug stability and bioavailability.
Another object of the present invention is to provide an eye drop with ionic buffer system in ophthalmic dosage with a suitable pH range compatible with the eye and effective for the drug.
Another object of the present invention is to provide an eye drop with ionic buffer system in ophthalmic dosage with optimal pH of the tear film around 7.4 to avoid irritation or minimize the discomfort in eye and ensure proper drug stability and bioavailability.
Another object of the present invention is to provide an ophthalmic composition with suitable ionic sstrength and osmolarity of the solution to match the isotonicity of the tear fluid to prevent any discomfort due to hypertonic or hypotonic solutions.
Another object of the present invention is to provide a low dose eye drops based on Atropine Sulfate concentration ranging from 0.01% w/v to 0.05% w/v.
Another object of the present invention is to maintain manufacturing process temperature between 2°C to 12°C; preferably 2°C to 8°C.
Another object of the present invention is to provide an ophthalmic composition with ionic buffer system enhancing the stability of Atropine Sulfate to improve the shelf-life of the product.
Another object of the present invention is to provide an ophthalmic composition with ionic buffer system ensuring pH stability to maintain a stable pH in the atropine eye drop solution throughout its shelf life.
Another object of the present invention is to provide an effective composition which can effectively deliver Atropine 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 eye drop with stable pH range ensuring that atropine remains in its optimal form to maintain atropine’s effectiveness as a mydriatic and cycloplegic agent.
Another object of the present invention is to provide an ophthalmic solution minimizing irritation and discomfort during and after application.
Another object of the present invention is to provide an ophthalmic solution with stable ionic buffer system maintaining a pH close to the natural pH of the eye to reduce the likelihood of irritation or stinging and enhancing patient compliance and comfort.
Another object of the present invention is to provide an ophthalmic solution with stable ionic buffer system capable in solution of neutralizing both acids and bases and thereby maintaining the original acidity or basicity of the solution.
Another object of the present invention is to provide an Atropine Sulfate based ophthalmic composition eye drop with stable ionic buffer including for e.g., boric acid, borax, citric acid, disodium hydrogen phosphate, e-aminocaproic acid but not limited to this.
Another object of the present invention is to provide an Atropine Sulfate based ophthalmic composition stabilized with ionic buffer system that contains buffers, polyols, chelating agent, tonicity modifier and or viscosity enhancer. It functions as an oxidizing preservative with antibacterial and antifungal properties. The components quickly degrade upon contact with cations on the ocular surface resulting.
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: Illustrates the Chemical structure of Atropine and mechanism of action of Atropine in myopia
DETAILED DESCRIPTION OF THE INVENTION:
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 Atropine Sulfate Ophthalmic solution composition stabilized with ionic-buffer eye drop for treating myopia in all age group especially in children. Atropine is the best-known member of a group of drugs known as muscarinic antagonists, which are competitive antagonists of acetylcholine at muscarinic receptors.
In an embodiment, the present invention provides an Atropine Sulfate Ophthalmic solution composition with optimal pH of the solution ensuring that atropine remains in its optimal form to maintain atropine’s effectiveness as a mydriatic and cycloplegic agent for effective working of solution in curing myopia.
In an embodiment, the present invention provides an Atropine Sulfate Ophthalmic solution composition with stable ionic buffer system maintaining a pH close to the natural pH of the eye to reduce the likelihood of irritation or stinging and enhancing patient compliance and comfort.
In an embodiment, the present invention provides Atropine Ophthalmic Solution with concentration ranging from 0.01% w/v to 0.05% w/v. The composition of the present invention comprises of Atropine Sulfate along with various other components which extends shelf life, increases bioavailability and minimizes ocular irritation.
In an embodiment, the composition comprises following components:
• Dynamic ionic buffer systems: The formulation includes a proprietary vehicle that enhances the absorption and bioavailability of Atropine sulfate 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 Atropine Sulfate in the eye. This specific formulation enhances the delivery and consistency of the drug's action.
Invention covers following buffer systems for stable formulation of atropine.
1.Phosphate Buffers: Phosphate buffers are frequently used due to their effective pH range and compatibility with a wide range of drugs. They are made from combinations of sodium dihydrogen phosphate and sodium monohydrogen phosphate with concentration ranging from 0.05 to 1.0% w/v, providing a stable pH environment.
2. Citrate Buffers: Citrate buffers, made from citric acid and its salts (like sodium citrate), Concentration ranging from citric acid 0.01 to 1.0% w/v & 0.1 to 0.5% w/v of sodium citrate.
They are useful for buffering in a slightly acidic to neutral pH range and are often used when phosphate buffers might interact adversely with other ingredients.
3. Boric Acid and Borax Buffers: Boric acid solutions can be used to maintain a near-neutral pH. They are relatively mild and less likely to cause irritation, making them suitable for some ophthalmic formulations.
Boric acid concentration ranging from 1.0 to 2.5% w/v & Borax is used at concentrations ranging from 0.1 to 0.5% w/v
Ionic buffer system also self-acts as antimicrobial preservative activity. It prevents microbial contamination during storage and use.
4. Polyols containing buffer system: Polyols like glycerol and sorbitol are used to retain moisture, helping to prevent the formulation from drying out and maintaining the hydration of the eye surface. Polyols can stabilize ophthalmic solutions by preventing the crystallization of active ingredients or other excipients. For example, mannitol is commonly used for this purpose. Concentration ranging from 2 % w/v to 10% w/v.
Polyols are osmotically active, they help to adjust the tonicity of the ophthalmic solution to match that of the tear fluid, making the formulation more comfortable when applied to the eye. Glycerin, mannitol, and sorbitol are typical polyols used for this purpose.
5. Viscosity Enhancers: Propylene glycol is used to increase the viscosity of the formulation, which can help in prolonging the contact time of the drug with the ocular surface. Present invention is used propylene glycol with concentration ranging from 2 % w/v to 10 % w/v.
6. Chelating agent: Di sodium ethylenediaminetetraacetic acid is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a poly amino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. Notably disodium EDTA with concentration ranging from 0.005% w/v to 0.1% w/v.
7. Tonicity modifier: The present invention described tonicity modifiers to adjust the osmolarity of the formulation to make it isotonic with the natural tear fluid. This is crucial for ensuring that the eye drop is comfortable upon application and does not cause irritation or disrupt the natural tear film. Natural tears have an osmolarity of approx. 300mOsm/L. In present invention, Sodium chloride and Zinc chloride are used as tonicity modifier. Concentration range of sodium chloride is 0.5 %w/v to 5% w/v and
0.01% w/v to 0.25% w/v of Zinc chloride. In present invention zinc chloride also used for its mild astringent and antiseptic properties in eye drops.
Packaging material selection: Proposed packaging configuration of Atropine ophthalmic solution is green LDPE bottles.
In an embodiment, the concentration ranging from 0.01% w/v to 0.05% w/v of Atropine Sulfate is carefully selected to balance efficacy and minimize side effects, ensuring safety and comfort for patients or users.
This 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 Dynamic ionic buffer solution
• Step-2 is Preparation of Active component solution; Maintain the manufacturing temperature between 2°C to 12°C; preferably 2°C to 8°C.
• Step-3 is Preparation of final bulk solution ss
• Step -4 is Filtration and filling of solution in LDPE bottles.
In a specific embodiment, the process of preparing the composition comprises following steps:
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 6.0 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/liter, preferably 280 to 400 mOsm/liter.
• 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 other studies to be performed
• Antimicrobial testing for Ionic buffer system till shelf life
• Preservative efficacy testing
• Extractable and Leachable Study (Stability time point 3M, 6M)
• Sterility
• Example 7:
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 invention of an ionic buffer system for atropine ophthalmic preparation addresses the need for maintaining a stable pH, ensuring drug stability and efficacy, enhancing patient comfort, and ensuring compatibility with other formulation components. By achieving these objectives, the buffer system helps to create a safe, effective, and user-friendly ophthalmic product.
Reduced Ocular Surface Toxicity: Ionic buffers are less likely to cause cellular damage or inflammation, which is crucial for patients requiring long-term ophthalmic treatment.
Better Tolerability: Ionic buffers are often better tolerated by patients with sensitive eyes or those suffering from conditions like dry eye disease.
Compatibility with Ocular Tissues: Ionic buffers are designed to mimic natural tear components or break down into non-toxic substances, reducing the risk of irritation or adverse effects.
Improved Patient Compliance: Due to their gentler nature, ionic buffer preservatives can lead to better patient adherence to treatment regimens
In view of the above the present invention provides an eye drop based on an Atropine Sulfate Ophthalmic solution composition with stable ionic buffer system which can effectively deliver Atropine to the target tissues, maximizing its therapeutic benefits while reducing systemic exposure and potential side effects and curing myopia and inhibiting the growth of myopia in all age group especially in children.
The Invention is further described with the help of non-limiting experiments:
Formulation Development Study
1) Selection of Buffer System: The formulation includes a proprietary vehicle that enhances the absorption and bioavailability of Atropine sulfate 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 Atropine Sulfate in the eye. This specific formulation enhances the delivery and consistency of the drug's action.
Development trails are covers following buffer systems for stable formulation of atropine.
1.Phosphate Buffers: Phosphate buffers are frequently used due to their effective pH range and compatibility with a wide range of drugs. They are made from combinations of sodium dihydrogen phosphate and sodium monohydrogen phosphate with concentration ranging from 0.05 to 1.0% w/v, providing a stable pH environment.
2. Citrate Buffers: Citrate buffers, made from citric acid and its salts (like sodium citrate), Concentration ranging from citric acid 0.01 to 1.0% w/v & 0.1 to 0.5% w/v of sodium citrate.
They are useful for buffering in a slightly acidic to neutral pH range and are often used when phosphate buffers might interact adversely with other ingredients.
3. Boric Acid and Borax Buffers: Boric acid solutions can be used to maintain a near-neutral pH. They are relatively mild and less likely to cause irritation, making them suitable for some ophthalmic formulations.
Boric acid concentration ranging from 1.0 to 2.5% w/v & Borax is used at concentrations ranging from 0.1 to 0.5% w/v
Ionic buffer system also self-acts as antimicrobial preservative activity. It prevents microbial contamination during storage and use.
Analytical results: Following comparative analytical results of batches using different buffer systems: boric acid–borax buffer, citrate buffer, and phosphate buffer systems.
Test Parameters Specification Borate buffer system Citrate buffer system Phosphate buffer system
Initial 6-month 25°C/60%RH 6- month
40°C/75%RH Initial 6-month 25°C/60%RH 6- month
40°C/75%RH Initial 6-month 25°C/60%RH 6- month
40°C/75%RH
Description Clear Colourless solution Complies Complies Complies Complies Complies Complies Complies Complies Complies
pH 3.5- 6.0 5.37 5.40 5.40 5.28 5.30 5.28 5.68 5.69 5.69
Osmolality (mOsmol/kg) 280-480 435 432 434 409 408 409 472 478 475
Assay of Atropine Sulfate (%) 90-110 110.01 108.65 102.28 109.98 109.78 108.12 107.55 105.79 101.17
Related Substances (%)
Impurity-A NMT 7 ND 0.307 1.15 ND 2.57 2.89 ND 1.20 2.41
Impurity-B NMT 1 ND ND ND ND ND ND ND ND ND
Impurity-C NMT 1 ND ND ND ND ND ND ND ND ND
Any unspecified
impurity (RRT) 2.20 ND ND 0.62 ND ND ND ND ND ND
2.40 ND ND ND ND ND 0.08 ND ND ND
2.75 NMT 1 ND ND ND ND ND ND ND ND ND
3.30 0.13 ND ND ND ND ND 0.061 ND ND
5.70 0.048 ND 0.47 0.03 0.20 0.27 ND ND ND
Total impurity NMT 7.0 0.178 0.31 2.24 0.03 2.81 3.24 0.061 1.20 2.53

Observation:
1. All formulations across all buffer systems meets the specification over a period of 6Month stability. The pH of all formulations remained within the specification range (3.5–6.0).
2. The Osmolality all buffer systems fell within the acceptable osmolality range (250–500 mOsmol/kg).
3. The Assay of Atropine Sulfate All formulations met the specification (90–110%).
4. The Related Substances; Impurity A increased over time in all systems under accelerated conditions. Highest in borate buffer at 40°C/75%RH (4.84%)—still within spec. Phosphate and citrate buffers showed lower levels of Impurity A at 2.41% and 2.57%, respectively. Impurities B and C remained not detected (ND) in all cases.
Unspecified impurities and total impurities remained below limits in all formulations, with Borate buffer showing highest total impurity at 6 months (5.31%). Phosphate buffer had lowest impurity profile overall (max 2.53%).
Conclusions:
1. All three buffer systems are suitable for developing Atropine Sulfate ophthalmic solution at 0.01% w/v based on appearance, pH, and osmolality.
2. Phosphate buffer system exhibited:
o Showed higher assay values, slightly above the upper limit
o Moderate impurity formation
o Good pH and osmolality balance, but assay drift may warrant adjustment
3. Citrate buffer system:
o Acceptable but showed the highest degradation (impurities) under stress
o Potential chemical instability over time.
4. Borate buffer system:
o Most stable assay values within spec
o Lowest total impurity formation, even under accelerated conditions
o Best overall impurity profile, making it the most favorable buffer system
Based on impurity control, assay stability, and physicochemical parameters, the Borate buffer and Phosphate buffer system is recommended for further development and scale-up of Atropine Sulfate 0.01% ophthalmic solution
2) pH Optimization studies
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 6.0 this ranges, preferably pH 3.0 to 6.0 With the proposed following pH were evaluated for product stability.
2.1) By using phosphate buffer
- pH at Lower side at pH 3.00
- pH at middle side at pH 5.00
- pH at Higher side at pH 6.00

Table 1: Formulation Composition: Batch Size: 500ml
pH at 3.00
S. No Ingredients Composition (% w/v/) Composition (mg/ml) Composition
(/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Sodium Phosphate monobasic 0.5 5 2.5
4. Sodium Phosphate dibasic 0.1 1 0.5
5. Mannitol 0.25 2.5 1.25
6. Propylene glycol 0.8 8 4
7. Sodium chloride 0.8 8 4
8. Hydrochloric acid q.s to pH 3.0 q.s to pH 3.0 q.s to pH 3.0
9. Water for injection q.s to 100ml q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.78
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.78
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.23
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.21
Step-5: Check pH of solution and adjust at pH 3.00 by using 1N Hydrochloric acid. (Standard limit of pH 3.5-6) Clear 3.01
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 3.02
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 3.01
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 3.02

Table 2: Formulation Composition: Batch Size: 500ml
pH at 5.00
S. No Ingredients Composition (% w/v/) Composition (mg/ml) Composition
(/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Sodium Phosphate monobasic 0.5 5 2.5
4. Sodium Phosphate dibasic 0.1 1 0.5
5. Mannitol 0.25 2.5 1.25
6. Propylene glycol 0.8 8 4
7. Sodium chloride 0.8 8 4
8. Hydrochloric acid q.s to pH 5.0 q.s to pH 5.0 q.s to pH 5.0
9. Water for injection q.s to 100ml q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.87
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.79
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.27
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.26
Step-5: Check pH of solution and adjust at pH 5.00 by using 1N Hydrochloric acid. (Standard limit of pH 3.5-6) Clear 5.01
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 5.01
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 5.00
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 5.02

Table 3: Formulation Composition: Batch Size: 500ml
pH at 6.00
S. No Ingredients Composition (% w/v/) Composition (mg/ml) Composition
(/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Sodium Phosphate monobasic 0.5 5 2.5
4. Sodium Phosphate dibasic 0.1 1 0.5
5. Mannitol 0.25 2.5 1.25
6. Propylene glycol 0.8 8 4
7. Sodium chloride 0.8 8 4
8. Sodium Hydroxide q.s to pH 6.0 q.s to pH 6.0 q.s to pH 6.0
9. Water for injection q.s to 100ml
q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.79
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.82
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.27
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.26
Step-5: Check pH of solution and adjust at pH 6.00 by using 1N Hydrochloric acid (Standard limit of pH 3.5-6) Clear 6.01
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 6.02
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 6.01
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 6.02

Table 4: Comparative Analytical data of pH 3.0; pH 5.0; and pH 6.0
Test Parameters Specification pH Optimization study
pH at 3.00
Initial pH at 5.00
Initial pH at 6.00
Initial
Description Clear Colourless solution Complies Complies Complies
pH 3.5- 6.0 2.99 5.65 6.04
Osmolality (mOsmol/kg) 280-480 468 472 469
Assay of Atropine Sulfate (%) 90-110 106.4 107.55 106.7
Related Substances (%)
Impurity-A NMT 7 1.9 ND 0.88
Impurity-B NMT 1 ND ND ND
Impurity-C NMT 1 ND ND ND
Any unspecified
impurity (RRT) 2.20 ND
ND ND ND ND
2.40 ND ND ND
2.75 ND ND ND
3.30 0.78 0.161 ND
4.37 ND ND ND
5.70 ND ND ND
Total impurity NMT 7.0 2.68 0.161 0.88

Observation: The physical and chemical Characteristics at pH 5.00, The solution was clear and Colorless. pH (5.65), osmolality (472 mOsmol/kg), and assay (107.55%) were all within acceptable limits. Impurity profile was minimal, with total impurities at only 0.161%, indicating good chemical stability.
Eye Irritation Test: Despite the acceptable physical and chemical profile, ocular irritation was observed in the pH 5.00 formulation during eye irritation testing (likely due to buffer species, osmolality, or pH sensitivity).
This outcome indicated that the formulation, while chemically acceptable, may not be well-tolerated for ophthalmic use at that condition.
Conclusion:
Although the phosphate-buffered formulation at pH 5.00 showed good stability and purity, the eye irritation observed makes it unsuitable for ophthalmic use.
To improve ocular tolerability, the decision was made to switch to a borate buffer system, which has milder buffering capacity is commonly used in ophthalmic products
2.2) By using Borate buffer
- pH at Lower side at pH 3.00
- pH at middle side at pH 5.00
- pH at Higher side at pH 6.00
Table 5: Formulation Composition: Batch Size: 500ml
pH at 3.00
S. No Ingredients Composition (% w/v/) Composition (mg/ml) Composition
(/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Boric acid 1.8 5 2.5
4. Sorbitol solution 70% 0.25 1 0.5
5. Propylene glycol 0.8 8 4
6. Zinc chloride 0.003 0.03 0.015
7. Hydrochloric acid q.s to pH 3.0 q.s to pH 3.0 q.s to pH 3.0
8. Water for injection q.s to 100ml q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.78
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.78
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.23
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.21
Step-5: Check pH of solution and adjust at pH 3.00 by using 1N Hydrochloric acid. (Standard limit of pH 3.5-6) Clear 3.01
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 3.02
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 3.01
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 3.02

Table 6: Formulation Composition: Batch Size: 500ml
pH at 5.00
S. No Ingredients Composition (% w/v/) Composition (mg/ml) Composition
(gm/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Boric acid 1.8 5 2.5
4. Sorbitol solution 70% 0.25 1 0.5
5. Propylene glycol 0.8 8 4
6. Zinc chloride 0.003 0.03 0.015
7. Hydrochloric acid q.s to pH 3.0 q.s to pH 3.0 q.s to pH 3.0
8. Water for injection q.s to 100ml q.s to ml q.s to 500ml
9. Water for injection q.s to 100ml q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.87
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.79
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.27
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.26
Step-5: Check pH of solution and adjust at pH 5.00 by using 1N Hydrochloric acid. (Standard limit of pH 3.5-6) Clear 5.01
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 5.01
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 5.00
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 5.02

Table 7: Formulation Composition: Batch Size: 500ml
pH at 6.00
S. No Ingredients Composition
(% w/v/) Composition (mg/ml) Composition
(/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Boric acid 1.8 5 2.5
4. Sorbitol solution 70% 0.25 1 0.5
5. Propylene glycol 0.8 8 4
6. Zinc chloride 0.003 0.03 0.015
7. Hydrochloric acid q.s to pH 3.0 q.s to pH 3.0 q.s to pH 3.0
8. Water for injection q.s to 100ml q.s to ml q.s to 500ml
9. Water for injection q.s to 100ml
q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.79
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.82
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.27
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.26
Step-5: Check pH of solution and adjust at pH 6.00 by using 1N Hydrochloric acid (Standard limit of pH 3.5-6) Clear 6.01
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 6.02
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 6.01
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 6.02

Table 8: Comparative Analytical data of pH 3.0; pH 5.0; and pH 6.0
Test Parameters Specification pH Optimization study with borate buffer
pH at 3.00
Initial pH at 5.00
Initial pH at 6.00
Initial
Description Clear Colourless solution Complies Complies Complies
pH 3.5- 6.0 4.18 5.08 5.86
Osmolality (mOsmol/kg) 280-480 301 299 299
Assay of Atropine Sulfate (%) 90-110 105.19 106.4 107.29
Related Substances (%)
Impurity-A NMT 7 3.07 0.01 3.00
Impurity-B NMT 1 ND ND ND
Impurity-C NMT 1 ND ND ND
Any unspecified
impurity (RRT) 2.20 NMT 1 ND ND ND
2.40 ND ND ND
2.75 ND ND ND
3.30 ND ND ND
4.37 ND ND ND
5.70 ND ND ND
Total impurity NMT 7.0 3.07 0.01 3.00

Conclusion:
The borate buffer system demonstrated excellent physical and chemical stability across the tested pH range (3.00 to 6.00).
Osmolality remained close to physiological levels (~300 mOsmol/kg), indicating good ocular comfort potential.
Impurity levels, especially Impurity-A, were consistent and well within the acceptable range, with no unspecified impurities detected.
Assay values remained within specification, confirming formulation stability at both acidic and near-neutral pH.
Given the earlier observation of eye irritation with phosphate buffer, the borate buffer system is a suitable and better-tolerated alternative.

3) Effect of Temperature: Trial batches were prepared with borate buffer to evaluate the impact of autoclaving (thermal sterilization) 121°C for 30 min on the drug product.
Table 9: Formulation Composition: Batch Size: 500ml
pH at 5.00
S. No Ingredients Composition (% w/v/) Composition (mg/ml) Composition
(gm/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Boric acid 1.8 5 2.5
4. Sorbitol solution 70% 0.25 1 0.5
5. Propylene glycol 0.8 8 4
6. Zinc chloride 0.003 0.03 0.015
7. Hydrochloric acid q.s to pH 3.0 q.s to pH 3.0 q.s to pH 3.0
8. Water for injection q.s to 100ml q.s to ml q.s to 500ml
9. Water for injection q.s to 100ml q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.68
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.88
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.34
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.28
Step-5: Check pH of solution and adjust at pH 5.00 by using 1N Hydrochloric acid. (Standard limit of pH 3.5-6) Clear 5.53
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 5.55
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 5.53
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 5.53

Table 10: Comparative Analytical data of Atropine Ophthalmic Solution 0.01% w/v

Observation:
Autoclaving at 121°C for 20 minutes had minimal impact on pH, osmolality, and assay of the atropine sulfate ophthalmic solution. However, it resulted in a significant increase in total impurities (from 3.00% to 5.42%), including an unspecified impurity at RRT 2.20 (2.14%), which exceeds the allowable limit.
Conclusion:
Autoclaving is not suitable due to the formation of an above-limit unspecified impurity. Aseptic filtration is recommended as an alternative sterilization method to ensure product quality and regulatory compliance.
Based on the above analytical data, the borate buffer system was selected as the optimized formulation, and it was subsequently evaluated under ICH stability conditions.
ICH stability study:
ICH stability studies were conducted on the optimized borate buffer formulation at 0, 3, and 6 months under the following conditions: 25°C/65% RH, 30°C/65% RH, and 40°C/75% RH.
Table 11: Formulation Composition: Batch Size: 500ml
S. No Ingredients Composition (% w/v/) Composition (mg/ml) Composition
(gm/500ml)
1. Atropine Sulfate 0.01 0.1 0.05
2. Di-Sodium Edetate 0.05 0.5 0.25
3. Boric acid 1.8 5 2.5
4. Sorbitol solution 70% 0.25 1 0.5
5. Propylene glycol 0.8 8 4
6. Zinc chloride 0.003 0.03 0.015
7. Hydrochloric acid q.s to pH 5.5 q.s to pH 5.5 q.s to pH 5.5
8. Water for injection q.s to 100ml q.s to ml q.s to 500ml
9. Water for injection q.s to 100ml q.s to ml q.s to 500ml
Manufacturing Procedure Clarity of solution pH
Step-1: Collect Water for Injection (90%of batch size) into compounding vessel and purged with Nitrogen for 10min. Clear 5.89
Step-2: Dissolve dispensed quantity of Di sodium EDTA to above and stir till a clear solution was obtained Clear 3.98
Step-3: Add dispensed quantity of Sodium phosphate monobasic, Sodium phosphate dibasic, Sodium chloride, Mannitol, Propylene glycol in to step 2. solution. Clear 6.39
Step-4: Add and dissolved Atropine sulphate under continuous stirring and purging to get clear solution. (Note: Before addition of Atropine sulphate maintain the temperature of solution between 8-12°C) Clear 6.29
Step-5: Check pH of solution and adjust at pH 5.50 by using 1N Hydrochloric acid. (Standard limit of pH 3.5-6) Clear 5.52
Step-6: Makeup to final volume with WFI and stir for 10 minutes and check pH of solution. Clear 5.51
Step-7: Check pH of solution (standard limit of pH 3.5-6) Clear 5.52
Step-8: Filter the bulk solution through 0.2µ Nylon filter and filled in LDPE bottles. Clear 5.52

Table 12: Analytical results; following comparative ICH stability data of optimised formulation of Atropine Ophthalmic Solution USP, 0.01%w/v
Test Parameters Specification Stability condition: 25°C/60%RH Stability condition: 30°C/65%RH Stability condition: 40°C/75%RH
Initial 3-month 6- month 3-month 6- month 3-month 6- month
Description Clear Colourless solution Complies Complies Complies Complies Complies Complies Complies
pH 3.5- 6.0 5.43 5.37 5.32 5.38 5.26 5.37 5.30
Osmolality (mOsmol/kg) 280-480 416 416 410 418 414 417 412
Assay of Atropine Sulfate (%) 90-110 105.0 105.17 104.11 104.90 98.96 102.78 99.77
Related Substances (%)
Impurity-A NMT 7 ND 1.45 1.64 1.48 2.64 ND 4.23
Impurity-B NMT 1 ND ND ND ND ND ND ND
Impurity-C NMT 1 ND ND ND ND ND ND ND
Any unspecified
impurity (RRT) 2.20 0.073 ND ND ND 0.75 ND 0.75
2.40 ND ND ND ND ND ND ND
3.50 NMT 1 0.166 ND ND ND ND ND ND
3.90 0.033 ND ND ND ND 0.061 ND
4.34 0.049 ND ND ND ND ND ND
Total impurity NMT 7.0 0.449 1.45 1.64 1.48 3.39 0.061 4.98

Conclusion: The optimized borate buffer formulation of Atropine Ophthalmic Solution USP, 0.01% w/v, demonstrated good physical and chemical stability under ICH conditions up to 6 months. All parameters, including assay, pH, osmolality, and impurities, remained within acceptable limits, supporting the formulation's suitability for long-term stability.
Experiments conducted with various formulations, outside the claimed composition, revealed drawbacks that adversely affected their overall performance. Notably, issues such as ocular irritation and reduced bioavailability of the active pharmaceutical ingredient, Atropine Sulfate, were observed.
Ocular irritation appeared to stem from formulation-related factors, such as the presence of incompatible excipients or inappropriate pH levels, which did not align well with the physiological conditions of the eye. This likely resulted in discomfort, redness, or tearing upon administration. Such effects can diminish patient compliance and may also shorten the drug's retention time on the ocular surface, thereby limiting its therapeutic potential.
In addition to tolerability concerns, reduced bioavailability indicated inefficiencies in drug delivery. Several contributing factors may include rapid precorneal drug loss due to blinking and tear turnover, insufficient formulation viscosity, or poor permeation characteristics of the delivery vehicle. These limitations hinder the effective absorption of Atropine Sulfate through ocular tissues.
,CLAIMS:We Claim:
1. An Atropine Sulfate based ophthalmic composition for the treatment of myopia comprising the components of:
a) Atropine Sulfate concentration ranging from 0.01% w/v to 0.05% w/v;
b) Chelating agent present in the concentration of 0.05% w/v;
c) a dynamic ionic buffer system composition which is preservative free comprising:
i. Buffering agent present in the concentration of 1.8% w/v;
ii. Polyols present in the concentration of 0.8 % w/v;
iii. Viscosity Enhancer present in the concentration of 0.25% w/v;
iv. Tonicity modifier present in the concentration of 0.003 %w/v.
2. The composition as claimed in claim 1, wherein Buffering agent comprises Boric acid.
3. The composition as claimed in claim 1, wherein polyols comprises propylene glycol or Sorbitol.
4. The composition as claimed in claim 1, wherein Viscosity Enhancer comprises propylene glycol or Sorbitol.
5. The composition as claimed in claim 1, wherein Tonicity modifier comprises Zinc chloride.
6. The composition as claimed in claim 1, wherein the pH is in the range of 3.0 to 6.0.
7. The composition as claimed in claim 1, wherein the osmolarity is in the range of 320 to 500 mOsm/liter.
8. A process of preparing the Atropine Sulfate based ophthalmic composition for the treatment of myopia comprising the steps of:
a) Preparation of a dynamic ionic buffer solution which is preservative free;
b) Preparation of Active component solution and maintaining the manufacturing temperature between 2°C to 12°C, preferably 2°C to 8°C;
c) Preparation of final bulk solution followed by the filtration and filling of solution in LDPE bottles.