The following types of lactose has the disadvantage of undergoing Maillard reaction of reaction with amine drugs and alkaline lubricants, EXCEPT:

• A. Regular Lactose
• B. Coarse Lactose
• C. Anhydrous Lactose
• D. Spray Dried Lactose

Answer: (C)

Maillard reaction is a non-enzymatic browning that happens when a reducing sugar reacts with amino groups, especially under alkaline conditions and with some moisture. Lactose can act as a reducing sugar because its glucose part has a free anomeric carbon, so it can react with amine-containing drugs or lubricants and cause browning and degradation.

Regular lactose and coarse lactose present ample contact between the reducing ends and amine sites, and spray-dried lactose, with its high surface area and moisture uptake, provides even more opportunities for reaction. These forms thus have a real disadvantage in formulations with amine drugs or alkaline lubricants.

Anhydrous lactose, on the other hand, has very low water content. The Maillard reaction requires a certain level of moisture to proceed efficiently, and the dry state greatly slows the reaction, making this form much less prone to such interactions. That reduced reactivity is why it’s the exception among the lactose types in this context. In practice, using anhydrous lactose helps minimize Maillard-related issues in sensitive combinations.