Ingredients:

- Diclofenac sodium 4% w/w

- Ethanol 96% v/v

- Propylene glycol USP

- Carbomer 940 USP

- Triethanolamine USP

- Methyl paraben IP

- Purified water IP

Preparation:

Step 1: Dissolving Carbomer 940

- Slowly add Carbomer 940 to a portion of the purified water while mixing continuously until a uniform dispersion is obtained.

Step 2: Mixing Propylene Glycol and Ethanol

- In a separate container, mix propylene glycol and ethanol.

Step 3: Adding Diclofenac Sodium

- Add diclofenac sodium to the mixture of propylene glycol and ethanol and stir until completely dissolved.

Step 4: Combining Carbomer Dispersion with Diclofenac Solution

- Gradually add the carbomer dispersion to the diclofenac solution while stirring continuously. Ensure thorough mixing to obtain a uniform gel.

Step 5: Adjusting pH

- Adjust the pH of the gel to approximately 6.5-7.0 using triethanolamine.

Step 6: Adding Preservative

- Add methyl paraben as a preservative to prevent microbial contamination.

Step 7: Final Volume Adjustment

- Adjust the final volume of the gel by adding additional purified water, if necessary.

Step 8: Homogenization

- Homogenize the gel using a suitable homogenizer to ensure a uniform consistency and dispersion of the ingredients.

Step 9: Filling and Packaging

- Fill the gel into appropriate spray containers or bottles and seal them securely.

Step 10: Labeling

- Affix appropriate labeling to the containers, including product name, instructions for use, storage conditions, and any necessary warnings or cautions.

Note:

It's important to follow good manufacturing practices (GMP) and quality control procedures during the preparation of the diclofenac sodium 4% spray gel formula to ensure the safety, efficacy, and stability of the product.