What is the filling of the soft capsule?

Update:04 Jan 2022

Soft capsules can be filled with various oils or liquid drugs or suspensions that have no dissolving effect on gelatin, or solid drugs. The filled liquid content 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) Non-volatile liquids that are miscible with water such as polyethylene glycol and non-ionic surfactants.

3) Compatible with water but low volatile compounds such as glycerin, propylene glycol and isopropanol.

Usually the drug may absorb water, which will often cause the moisture in the soft capsule shell to change. If the drug is hydrophilic, the drug should be kept at 5% water. Oils are generally used as the drug's solvent or suspension medium, and filled with oil. Although soft capsules have no moisture, moisture or moisture in the capsule shell can penetrate through the capsule wall and enter them. If the drug is hydrophilic, 3% moisture should also be retained. The liquid medicine contains more than 50% water or contains low-molecular-weight and water-miscible volatile solvents such as ethanol, acetone, amines, acids and esters, etc., which can soften or dissolve soft capsules, so it is not suitable to be made into soft capsules ; When filling liquid drugs, the pH should be controlled between 2.5 and 7.5, otherwise the soft capsules may leak due to the acid hydrolysis of gelatin during storage. Strong alkalinity can denature the gelatin and affect the solubility of the soft capsules. Soft capsule equipment The iron content of the raw material gelatin used in the production of soft capsules should not exceed 0.0015% to avoid deterioration of iron-sensitive drugs.

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