The identification methods for enteric-coated gelatin empty capsules include: taking 0.25g of the product, adding 50ml of water, heating to dissolve, cooling, shaking well, taking 5ml of the solution, adding a few drops of potassium dichromate test solution-dilute hydrochloric acid (4:1), which produces an orange-yellow flocculent precipitate; taking 1ml of the solution from identification (1), adding 50ml of water, shaking well, adding a few drops of tannic acid test solution, which produces turbidity; taking about 0.3g of the product, placing it in a test tube, adding a small amount of soda lime, the generated gas can turn moist red litmus paper blue.
The test items include disintegration time, friability, loss on drying, density, sulfite, etc. In the disintegration time test, for both enteric-coated capsules and colonic enteric-coated capsules, take 6 capsules of the product, fill them with talc powder, and test according to the method under the corresponding item of the disintegration time test method; it should meet the requirements. The method for testing friability is as follows: Take 50 capsules of this product, place them in a watch glass, and put them in a desiccator containing a saturated magnesium nitrate solution. Maintain a constant temperature of 25℃±1℃ for 24 hours. Remove the capsules and immediately place each capsule individually into a glass tube (24mm inner diameter, 200mm long) standing upright on a wooden board (2cm thick). Allow a cylindrical weight (polytetrafluoroethylene, 22mm diameter, 20g±0.1g weight) to fall freely from the opening of the glass tube. Observe whether the capsules break. If any breakage occurs, no more than 5 capsules should be broken. For the loss on drying test, take 1.0g of this product, separate the cap and body, and dry at 105℃ for 6 hours. The weight loss should be 10.0%～16.0%. The methods for testing for tightness, sulfites, parabens, chloroethanol, ethylene oxide, residue on ignition, chromium, heavy metals, and microbial limits under the "Light-Gel Empty Capsules" section should all comply with the regulations.
The suitability studies of gelatin empty capsules and gelatin enteric-coated empty capsules should focus on the cross-linking that occurs within gelatin molecules, between gelatin molecules, between gelatin and drugs, and between gelatin and other materials over time. If cross-linking occurs and the dissolution of the formulation does not meet the requirements, a dissolution test can be conducted by adding a certain potency of pepsin or trypsin to the dissolution medium (in vitro-in vivo correlation studies should be carried out).
