Capsules classification and manufacture

DEFINITION
Capsules are solid preparations with hard and soft shells of various shapes and capacities, usually containing a single dose of active ingredients.

1. CAPSULES DEFINITION Capsules are solid preparations with hard and soft shells of various shapes and capacities, usually containing a single dose of active ingredients . Capsules are of two types Hard gelatin capsules 2. Soft gelatin capsules

2. ADVANTAGES DISADVANTAGES Capsules are tasteless, odorless and can easily be administered. They are attractive in appearance. The drugs having un-pleasant odor and taste are enclosed in a tasteless shell. They can be filled quickly and conveniently. They are economical. They are easy to handle and carry They are easily tampered They are subject to the effects of relative humidity and to microbial contamination. They may be difficult for some people to swallow. More expensive (commercially). Deliquescent materials cannot be incorporated, they may cause hardening or brittle capsules.

3. GELATIN •Gelatin is heterogeneous product derived by hydrolytic extraction of animal's collagen. • The sources of gelatins including animal bones, hide portions and frozen pork skin. TYPES OF GELATIN 1. TYPE -A Derived from acid treated precursor that exhibits an iso electric point at pH-9. It is manufactured mainly from pork skin. 2. TYPE -B Derived from alkali treated precursor that exhibits an isoelectric point at pH-4.7. It is manufactured mainly from animal bones

4. STEPS INVOLVED IN THE PREPRATION OF CAPSULES Dipping : Pairs of the stainless steel pins are dipped into the dipping solution to simultaneously form the caps and bodies Spinning : The pins are rotated to distribute the gelatin over the pins uniformly and to avoid the formation of a bead at the capsule ends Drying : The gelatin is dried by a blast of cool air to form a hard shells. The pins are moved through a series of air drying kilns to remove water Stripping  Stripping: A series of bronze jaws strip the cap and body portions of the capsules from the pin. T rimming and joining: The stripped cap and body portions are trimmed to the required length .After trimming to the right length, the cap and body portion are joined and ejected from the machine Polishing : Acela-cota pan is used to dust and polish. Cloth Dusting : Capsule are rubbed with cloth. Brushing : Capsule are feed under soft rotating brush. 

5. FILLING OF CAPSULE 1. RECTIFICATION -  The empty capsule are oriented, so that all points are in the same direction (i.e. body –end downward) the capsule pass one-at-a time, through a channel just wide enough to provide a frictional grip at the cap end. 2. SEPERATION OF CAP FROM BODY - H ere the rectified capsules are delivered body-end into the upper portion of the split bushing or shift filling rings. A vaccum applied from the below , pull the bodies down into the longer portion of the split bushings. The diameter of the caps is too large to allow them to follow the bodies into the lower bushing portion. The split bushing are then separated to expose the bodies for filling. 3. DOSING OF FILL MATERIAL -The prepared formulation is is filled into the body. 4. REPLACEMENT OF CAPS & EJECTION OF FILLED CAPSULES The cap and body bushing portion are required. Pins are used to push the filled bodies up into the caps for closures and to push the closed capsules out of the bushings. Compressed air also may be used to eject the capsule.

6. EVALUTION OF CAPSULES   WEIGHT VARIATION TEST 20 capsules are individually weighed, average weight and percentage deviation from the average weight is determined. Weight variation limits are average weight ± 10%. If the weight variations are beyond the limits, net weights (weight of the contents) are determined. The net weights of the not more than 2 capsules should fall outside the average net weight ± 10% values and net weight of no capsule should be outside the average net weight ±25% limit . If the net weights of 2-6 capsules deviate by ±10 to 25%, the net weights of 40 more capsule determined . out of the 60 capsules tested, the net weights of not more the 6 capsules should deviate from the average net weight by 10- 25% and none by more than 25%. If limits are ±10% when average weight < 300 mg and 7.5% when average weight is 300mg or more.

7. 2. UNIFORMITY OF DRUG CONTENT A sample of 30 capsule is taken and 10 are assayed individually. The drug content of a capsule should be within the limits of average drug content ±15% and the drug content of none of the capsule fall outside the average drug content ±25%. If 1-3 capsules falls outside the average drug content ±15%, the remaining 20 are assayed. The drug content of at least 27 out of 30 assayed should be within the average drug content ±15% limits. and the drug content of none of the capsules falls outside the average drug content ±25% limits. The test is prescribed for capsules when active ingredient is <10 mg or 10% of fill weight. 

8. 3. DISINTEGRATION TEST Disintegration test Capsules are not generally tested for disintegration, particularly, when the dissolution test is prescribed in the monograph, except when they are designed to be enteric by treatment of their shell with formaldehyde, which should be tested to ensure they do not disintegrate in the simulated gastric fluid . usual disintegration time limit is 60 min. Dissolution test Carried out by means of tablet dissolution test apparatus.

9. 4. DISSOLUTION TEST- The dissolution test is carried out using the dissolution apparatus official in both the U.S.P and I.P . The capsule is placed in a basket , and the basket is immersed in the dissolution medium and caused to rotate at a specified speed . The dissolution medium is held in a covered 1000ml glass vessel and maintained at 37*C +-0.5 *C by means of a constant temperature suitable water bath . RESULT Six capsules are tested and are accepted if each of them is not less than monograph specified i.e., p +5% If it fails then additional six capsules are tested the result is accepted if the avg. of 12 capsules is greater than or equal to p and none of them is less than p-15%. If the capsule still fails the test the additional 12 capsules are tested and are accepted if the avg. of 24 is greater than to p, if not more than two less than p-15% and none of them is less than p- 25 %.