Preparation and Evaluation of Tetracycline Capsules

Aim: Preparation and Evaluation of Tetracycline Capsules

References

1. United States Pharmacopeia (USP 43-NF 38, 2020).

2. Aulton, M.E. (2018). Pharmaceutics: The Science of Dosage Form Design. Churchill Livingstone.

3. Allen, L.V. (2020). Ansel’s Pharmaceutical Dosage Forms and Drug Delivery Systems. Lippincott Williams & Wilkins.

Objective

To prepare Tetracycline capsules and evaluate their quality in terms of weight variation, disintegration time, dissolution, and drug content uniformity.

Materials Required

Active Ingredient: Tetracycline Hydrochloride (HCl) 250 mg per capsule

Excipients: Lactose (as a filler), Microcrystalline Cellulose (as a disintegrant), Magnesium Stearate (as a lubricant), Sodium Starch Glycolate (as a super disintegrant)

Capsule Shell: Hard gelatin capsules (size 1 or 2, depending on the fill weight)

Equipment Required: Analytical Balance, Capsule Filling Machine (Manual or Semi-Automatic), Mortar and Pestle, Sieve (Mesh size: 40), Disintegration Tester, Dissolution Apparatus, UV-Visible Spectrophotometer, Friability Tester, Hardness Tester

Quantities of Ingredients (for 100 Capsules)

Tetracycline HCl: 25 g

Lactose: 15 g

Microcrystalline Cellulose: 5 g

Magnesium Stearate: 0.5 g

Sodium Starch Glycolate: 1 g

 Procedure

1. Weighing of Ingredients: Accurately weigh the required quantities of Tetracycline HCl, lactose, microcrystalline cellulose, magnesium stearate, and sodium starch glycolate using an analytical balance.

2. Blending of Ingredients:

• Transfer Tetracycline HCl, lactose, microcrystalline cellulose, and sodium starch glycolate into a mortar.
• Mix the ingredients thoroughly for uniform distribution of the drug and excipients.
• Add magnesium stearate and gently mix to ensure uniform distribution while avoiding over-lubrication.

3. Sieving: Pass the blended mixture through a 40 mesh sieve to ensure uniform particle size and remove any lumps.

4. Filling of Capsules:

• Load the sieved blend into a capsule-filling machine (manual or semi-automatic).
• Fill each hard gelatin capsule with the appropriate amount of the blend, aiming for an average fill weight of approximately 350-400 mg per capsule (depending on the size of the capsule shell used).
• Ensure proper locking of the capsules after filling.

5. Cleaning and Polishing: Clean the filled capsules using a clean cloth or a polishing machine to remove any powder residue on the surface.

 Evaluation of Tetracycline Capsules

1. Weight Variation:

• Weigh 5 individual capsules and calculate the average weight.
• Ensure the weight variation of individual capsules does not exceed ±5% of the average weight, according to pharmacopeial standards.

2. Disintegration Test:

• Place five capsules in the disintegration test apparatus containing water at 37°C.
• Record the time taken for all capsules to disintegrate completely.
• The disintegration time should not exceed 15 minutes.

3. Dissolution Test:

• Conduct a dissolution test using a dissolution apparatus with a suitable dissolution medium (e.g., 0.1N HCl) at 37°C.
• Withdraw samples at regular intervals (5, 10, 15, 30, 45, and 60 minutes) and measure the absorbance using a UV-Visible spectrophotometer at 276 nm.
• Calculate the percentage of Tetracycline released at each time point.

4. Assay for Drug Content Uniformity:

• Select 5 capsules randomly.
• Weigh each capsule and dissolve the contents in a suitable solvent (e.g., 0.1N HCl).
• Measure the absorbance using a UV-Visible spectrophotometer at the wavelength of maximum absorption (276 nm).
• Calculate the amount of Tetracycline HCl in each capsule and ensure it is within 85-115% of the label claim.

5. Friability Test (for Capsules): Subject the filled capsules to a friability test to ensure that they do not lose more than 1% of their weight after being subjected to mechanical stress.

 Sample Data Table

Conclusion: The prepared Tetracycline capsules comply with the standard specifications for weight variation, disintegration time, dissolution, and content uniformity, indicating that the formulation and preparation methods are appropriate for producing quality capsules.