Questions
3-5 questions per university paper
Difficulty
Medium
Importance
High yield for GPAT and semester exams
Overview
Tablets and liquid orals represent the most significant segment of solid and liquid dosage forms in pharmaceutical technology. Mastering this topic is essential for understanding drug delivery mechanics, stability, and patient compliance, forming a high-yield core for B.Pharm semester and competitive exams.
Tablet Manufacturing Methods
Tablets are produced primarily through wet granulation, dry granulation, or direct compression. The choice of method depends on the flowability and compressibility of the drug substance and excipients.
- Wet Granulation involves massing, granulation, drying, and compression.
- Dry Granulation (slugging or roller compaction) is for moisture-sensitive drugs.
- Direct Compression is ideal for substances with good flow and compressibility.
- Granulation improves flow properties and reduces dust during handling.
- Binding agents are critical in wet granulation to ensure granule integrity.
Tablet Coating Techniques
Coating is applied to tablets to mask bitter tastes, provide protection from environmental factors, or modify drug release profiles. Key processes include sugar coating, film coating, and enteric coating.
- Sugar coating is a multi-step process involving sub-coating and smoothing.
- Film coating uses thin polymer layers for rapid dissolution.
- Enteric coating prevents disintegration in the stomach (e.g., cellulose acetate phthalate).
- Pan coating or fluidized bed coating are common equipment types.
- Core testing involves friability and disintegration time measurements.
Liquid Dosage Forms: Syrups and Suspensions
Liquid orals are designed for rapid onset or ease of administration, particularly for pediatric or geriatric patients. Syrups are concentrated aqueous preparations of sugar, while suspensions involve finely divided insoluble drug particles dispersed in a liquid vehicle.
- Syrups typically contain 66.7% w/w sucrose to inhibit microbial growth.
- Suspensions require suspending agents to increase viscosity and prevent rapid settling.
- Stokes' Law (v = d^2(ρs - ρl)g / 18η) governs the sedimentation rate in suspensions.
- Flocculated suspensions form loosely bound aggregates that are easily redispersed.
- Deflocculated suspensions settle slowly but form a hard cake difficult to redisperse.
Formula Sheet
Stokes' Law: v = d^2(ρs - ρl)g / 18η
Friability: F = (W_initial - W_final) / W_initial * 100
Exam Tip
When describing manufacturing processes, always include a simple flow diagram; examiners prioritize logical flow over long, descriptive paragraphs.
Common Mistakes
- Confusing the purpose of enteric coating with film coating in descriptions.
- Neglecting to mention the importance of particle size reduction in Stokes' Law.
- Failing to differentiate between 'caking' and 'flocculation' in suspended systems.
More Revision Notes
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