Soft capsules can be filled with various oils or liquid […]
Soft capsules can be filled with various oils or liquid drugs or suspensions that do not dissolve gelatin. They can also be filled with solid drugs. The filled liquid contents can be divided into three categories:
1) Volatile or non-volatile liquids that are immiscible with water, such as vegetable oils or aromatic oils.
2) Water-miscible, non-volatile liquids such as polyethylene glycol and nonionic surfactants.
3) Compounds which are compatible with water and which are less volatile, such as glycerin, propylene glycol and isopropanol.
Usually, the drug may absorb water, which often causes changes in the moisture in the soft capsule. If the drug is hydrophilic, the drug should be kept at 5% water. The oil is generally used as a medium for the drug or a medium for the suspension, and the oil is filled. Although the soft capsule has no moisture, the moisture in the moisture or the capsule can enter the capsule wall and enter it. If the drug is hydrophilic, it should also retain 3% moisture.
Volatile solvents containing more than 50% water in the liquid or containing low molecular weight and water miscible, such as ethanol, acetone, amines, acids and esters, can soften or dissolve the soft capsules, so it is not suitable for making soft capsules. When filling liquid drugs, the pH should be controlled between 2.5 and 7.5. Otherwise, the empty capsules may leak due to acid hydrolysis of gelatin during storage. Strong alkalinity may denature gelatin and affect the solubility of soft capsules. Soft capsule equipment The iron content in the raw gelatin for the production of soft capsules should not exceed 0.0015% to avoid deterioration of iron-sensitive drugs.