Industrial Pharmacy

Study Notes

Definition: Capsules are solid dosage forms where the drug substance is enclosed within a water-soluble shell or envelope.
Capsule Shell Material: Primarily made of gelatin.
Intended Use: Primarily for oral administration, but can also be administered rectally or vaginally.
Advantages:
- Mask unpleasant tastes and odors of the drug.
- Smooth texture, becoming slippery when moist, facilitating swallowing.
- Gelatin's solubility at gastric pH ensures rapid drug release in the stomach.
- Visually appealing.
- Accurate dosage delivery.
- Tasteless and odorless when swallowed.
- Easily identifiable due to shape, color, and manufacturer markings.

Hygroscopic drugs cannot be encapsulated.
Concentrated preparations needing prior dilution are unsuitable due to potential stomach irritation.

Composition: A heterogeneous product derived from the hydrolytic extraction of animal collagen.
Sources: Often derived from animal bones, and frozen pork skin.
Types: Type A gelatin is derived from pork skin with acid treatment; Type B gelatin is derived from bones and animal skin by an alkaline process.
Solubility: Solubility properties differ based on pH.
Stability: Gelatin is stable in dry air but subject to microbial decomposition if moist.
Solubility in Water: Insoluble in cold water, soluble in hot water and warm gastric fluid.
Digestibility: A protein, digested by proteolytic enzymes.
Toxicity: Non-toxic.

Use: For solid medications.
Structure: Two parts - body and cap.
Color: Can be clear, colorless, or colored with FD&C/D&C dyes.
Moisture Content: Typically 13-16%.
Stability: Sensitive to high humidity and extreme dryness, which can affect their shape and integrity.
Packaging: Often packaged with drying agents (e.g., silica gel) to prevent moisture absorption.

Bench-scale (Punch) filling: Used for small numbers of capsules.
Manual filling machines: Used for regular/extensive preparation of capsules.
Industrial-scale filling machines: Semi- or fully-automated systems used for large-scale production of hard gelatin capsules. Capabilities can be for 5000 - 150000 capsules/hour. These machines have unique dosing systems for dispensing powder into shells. Some use independent measurement using a separate measuring device.
Important Considerations during Filling: To avoid dust/material adhering to the external shell, use of a polishing/cleaning stage is required after the filling is complete.

Cleaning: Cleaning procedures may include methods for a small-scale manufacturing and industrial-scale approaches. These may involve materials like gauze, or using a vacuum cleaning system.
Imprinting: Used for company and product identification.
Special Purpose Capsules: Can be tailored to control drug release rates (e.g., using special coverings).
Quality Control Tests:
- Capsule appearance (size, shape, color, thickness).
- Weight variation.
- Content uniformity.
- Disintegration test.
- Dissolution test.