Measuring The Integrity Of Hard Gelatin Capsules Using Texture Analysis
Extensive research has brought about multiple ways of administering drugs and therefore providing options to suit everyone. However, one of the most popular ways of administering drugs is in the form of gelatin capsules. Gelatin capsules have several advantages over conventional tablets as they are softer making them easier to swallow and they mask unpleasant tastes and smells of the contents when swallowing therefore promoting compliance. Gelatin capsules being largely protein are also readily soluble at body temperature and easily broken down by the digestive system easing the absorption of the drug into the body.
The integrity of the gel capsules can however be compromised based on the chemical nature of the filling and the relative humidity of the storage environment. The nature of the filling and humidity levels can affect the water content of gelatin which is critical in maintaining its structural and mechanical properties (Kozlov., 1983). Hydrophilic solvents for instance, are often used in small quantities to improve the dissolution of water-insoluble drugs. Such solvents however, are known to either soften or make brittle the gelatin shell. Furthermore, drug substances containing reactive aldehydes are also known to react with the gelatin forming cross-linkages with lysine residues between the gelatin strands and therefore stiffening the gelatin structure and consequently reducing the solubility of the capsule shell. Consequently, it is necessary to consider the formulation compatibility of a drug filling to the capsule shell as well as the storage environment in order to maintain the integrity of the capsule shell.