Capsules. Advantages of hard capsules. Manufacture of hard Capsules. Gelatin capsules. Nongelatin capsules. Conceal the smell. Improve drug stability

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1 Capsules School of Pharmacy Chen Jian Advantages of hard capsules Conceal the smell Improve drug stability Bioavailability is generally good Flexibility in formulation Obtain sustained-release Widely used in preliminary drug study Capsules are solid dosage forms in which the drug substance is enclosed within either a hard or soft soluble shell. Hard capsules Soft capsules Disadvantages of hard capsules Filling equipment slower than tableting Extra expense on shells Unsuitable for some kinds of drugs Highly soluble materials Water or alcohol solution of drugs Efflorescent materials Hygroscopic materials Gelatin capsules Generally the shells of capsules are formed from gelatin. Nongelatin capsules HPMC Staruch Manufacture of hard Capsules Gelatin is the most popular component to prepare capsule shells Gelatin is prepared by the hydrolysis of collagen obtained from animal connective tissue, bones, skin, and sinew. Type A Type B 1

2 Physicochemical properties of gelatin Bloom strength Size of shells Eight size: 000, 00, 0, 1, 2, 3, 4, 5 gives an indication of the firmness of the gel Viscosity Be vital to the control of the thickness of the cast film Other components in shell of hard capsules Plasticizer Thicker Colorant Opacifier Preservative Water Sealing and Self-locking closure Self locking Band sealing Spot welding Shell manufacture Gelatin dissolution Dipping Rotation Drying Stripping Trimming Joining Sorting Printing Oxygen permeation through size 00 gelatin capsules 2

3 The filling of hard gelatin capsules Rectification Separation of caps from bodies Dosing of fill material Replacement of caps and ejection of filled capsules Automatic filling machines Auger fill machines Vibratory fill machines Piston-tamp machines Dosing-disc machines Dosator machines Manufacture of Hard Capsules Powder filling Choice of shell Power filling General considerations of powder formulation Lubricity Flowability Compactibility Sealing Manual Filling Machines Nonpowder filling Beads/pellets Microtablets Liquid 3

4 Storage and package Temperature Humidity Trace aldehydes Disadvantages of soft capsule Unsuitable for some kinds of drugs Specialized manufacturing equipment requirements. Higher manufacturing cost as compared to tablets Stability concerns with compounds susceptible to hydrolysis. Soft Gelatin Capsules (softgels) Shell composition Gelatin Plasticizer: glycerin, sorbitol Water Advantages of soft capsule Solidify the liquid drug Improved bioavailability Enhanced drug stability Excellent dose uniformity Pharmaceutical elegance Superior patient compliance Requirements of filling material Water content lower than 5% No low MW water soluble and volatile organic compounds No aldehyde The ph of the liquids should be between 2.5 and 7.5 4

5 The types of vehicles Water-immiscible liquids Vegetable oils Aliphatic and aromatic hydrocarbons Water-miscible, nonvolatile liquids PEG All liquids used for filling must flow by gravity at a temperature of 35 or less. Enteric Capsules The shell of enteric capsules is soluble in intestine and insoluble in stomach The content of enteric capsules is soluble in intestine and insoluble in stomach Manufacture of softgels Rotary die process Bubble method Evaluation of capsules Appearance Weight variation Disintegration test Dissolution test Water content Learning Objectives Compatibility and stability concerns of softgels Increased interaction due to intimate contact between the shell and its liquid contents Loss of drug due to migration from vehicle into the shell. Shell composition of capsules Size of hard capsule shells Compatibility of drug and shell Manufacture methods of soft capsules 5