Capsule Coatings both natural and synthetic.pptx

about capsule coatings , synthetic and natural ones

1. Capsule Coating 1

2. A capsule coating is a thin protective layer applied to the outer surface of a capsule or tablet. Usage / Purpose: Masks unpleasant taste or odor. Protects the drug from moisture, light, and air. Controls the release rate of the drug. Improves appearance and swallowing. If coating is not used: Drug may degrade before reaching the target site. Unpleasant taste or odor. Reduced drug stability and shelf life. 2

3. Common Coating Materials: Gelatin – for soft and hard capsules. Hydroxypropyl methylcellulose (HPMC) – a plant-based alternative. Ethylcellulose – for controlled release. Eudragit polymers (acrylic copolymers) – for enteric (acid-resistant) coatings. Polyvinyl alcohol (PVA) – for film coatings. 3

4. Acid Sensitivity: Some drugs get destroyed by stomach acid. Enteric coatings resist stomach acid (pH ~1–3) and dissolve only in the intestine (pH > 5.5). Ensures safe drug delivery and absorption at the correct site. Alternatives to Traditional Coatings: Vegetable-based cellulose coatings Pullulan – a natural polysaccharide coating Starch-based coatings – biodegradable and plant-derived 4

5. Synthetic Coating Materials Type Examples Purpose / Function Cellulose derivatives Hydroxypropyl methylcellulose (HPMC), Hydroxypropyl cellulose (HPC), Ethyl cellulose Film coating, controlled release, enteric coating Synthetic polymers Polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP), Polyethylene glycol (PEG) Film-forming, plasticizer, improves appearance Methacrylic acid copolymers Eudragit® (various types like Eudragit L, S, RL, RS) Enteric or sustained-release coatings Cellulose acetate phthalate (CAP) – Enteric coating (resists gastric acid) Polyvinyl acetate phthalate (PVAP) – Enteric coating, delayed release Polyurethane and acrylic resins – Modified release and protection from moisture 5 These are man-made (chemically synthesized) substances designed to control capsule properties such as dissolution, protection, and drug release . 🔸 Advantages: Uniform coating, high stability, adjustable dissolution properties 🔸 Disadvantages: Costly, may require organic solvents during preparation

6. Natural Coating Materials These are obtained from natural sources such as plants, animals, or microbes They are biocompatible, biodegradable , and widely used for safe or eco-friendly formulations 🔸Advantages: Biodegradable, non-toxic, acceptable for food and pharma use. 🔸Disadvantages: Less mechanical strength, variable properties depending on source. 6

7. Type Examples Purpose / Function Proteins Gelatin Main material in hard and soft capsules; forms strong, flexible films Polysaccharides (plant-based) Starch, Cellulose, Pullulan, Guar gum, Xanthan gum Film coating, capsule shell formation Alginates Sodium alginate Controlled or sustained release coating Chitosan (from shellfish) – Mucoadhesive and biodegradable coating Carrageenan (from seaweed) – Used in vegetarian capsules Shellac – Natural resin used for enteric coatings Agar – Forms gel-type coating for certain formulations 7