(1) Oily drugs and low melting point drugs are most suitable for soft capsules. Oily drugs (such as vitamin E) and drugs that are liquid or semi-solid at normal temperature are usually treated by adsorption, solidification and other technologies during preparation in the past. The volume is increased due to the addition of auxiliary materials such as adsorbent, or the drugs need to be heated and dried during preparation. At this time, the drugs are easy to free or exude from auxiliary materials such as adsorbent, causing the loss of main drugs and affecting the curative effect. However, soft capsules dissolve oily drugs and low-melting drugs with fat-soluble solvent or make them into emulsion for filling or dripping pills, thus omitting adsorption auxiliary materials, not only miniaturizing the preparation, but also avoiding the problems of drug free and exudation. Such as vitex oil capsules and indomethacin farneside capsules.
(2) drugs that are sensitive to light, unstable when exposed to damp heat, or easy to oxidize can be made into soft capsules. Some drugs such as volatile oil are sensitive to light. Some drugs are easy to decompose and volatilize when exposed to damp heat. Some drugs are easy to oxidize during preparation and storage. In order to prevent the drug from decomposing when exposed to light, a light shielding material such as titanium dioxide or iron oxide can be added to the capsule material for preparing the capsule, and good light stability can be obtained. In order to prevent the medicine from contacting with air, inert gas can be introduced in the preparation process. The capsule material of soft capsule is composed of glycerin and gelatin, with thick wall and no air permeability. Therefore, soft capsule is an excellent preparation to prevent drug oxidation. Such as vitamin e capsules, active vitamin D3 capsules and luocaquan capsules.
(3) The soft capsule can be made into rectal suppository. The method comprises dissolving or making the main drug into oil soluble suspension to prepare soft capsule, and making the capsule into suppository. Compared with general suppositories, rectal capsule suppositories are easier to diffuse and absorb in rectum, and the preparation method is simpler and convenient to use than general suppositories.
(4) drugs with bad smell and trace active drugs. It is a well-known feature that soft capsules can cover up the bad smell of drugs. The dosage of some trace active drugs is very small, such as ajcalcitol and calcitriol (each containing 0.25μg), which are most suitable to be made into soft capsules.
