Can HPMC empty capsules be made opaque by dyeing or coating?

HPMC empty capsules can be made opaque through staining or coating treatment. HPMC (Hydroxypropyl Methylcellulose) empty capsules themselves have a certain degree of transparency, but in order to meet specific application requirements such as shading, improving appearance, or increasing functionality, they can be made opaque through dyeing or coating treatment.
Dyeing treatment usually involves adding colorants during the capsule preparation process to give the capsule the desired color as a whole while reducing transparency. Coating treatment is to cover the surface of the capsule with a layer of opaque material, such as special polymers or pigments, to achieve a light blocking effect. Both methods can effectively change the transparency of HPMC empty capsules, making them suitable for different packaging and storage requirements.
In practical applications, opaque treatment helps to protect the contents of capsules from light, extend the shelf life of drugs, and enhance the market appeal of products. For example, some light sensitive drugs may be packaged in opaque capsules to ensure their stability and effectiveness.