Capsule shells are made of gelatin or other substances, the consistency of which may be modified by the addition of substances such as glycerol or sorbitol. Similarly, Hypromellose Capsule Shell are composed of Hypromellose and water, and may also contain additives such as plasticizers, surfactants, gelling agents, dispersing agents, flavoring agents, antimicrobial agents, and sweeteners. They may contain opacifiers, colorants, and/or processing aids. They may be externally coated. They may be imprinted.
Since capsule shells material can support microbial growth hence it must meet the microbiological purity requirements. (Empty shells as raw material and finished product after filling the drug). Therefore, microbiological purity test (Total microbial count, yeast & molds, absence of pathogen -indicator organisms) should be included in the finished product specification of capsules as well as empty capsule shells.
Other physical & chemical tests should be included in the finished product specification of capsule product as per pharmacopoeial monograph requirements.