Interactions and incompatibilities of pharmaceutical excipients with active pharmaceutical ingredients: a comprehensive review.

Studies of active drug/excipient compatibility represent an important phase in the preformulation stage of the development of all dosage forms. The potential physical and chemical interactions between drugs and excipients can affect the chemical nature, the stability and bioavailability of drugs and, consequently, their therapeutic efficacy and safety. The present review covers the literaturereports of interaction and incompatibilities of commonly used pharmaceutical excipients with different active pharmaceutical ingredients in solid dosage forms. Examples of active drug/excipientinteractions, such as transacylation, the Maillard browning reaction, acid base reactions and physical changes are discussed for different active pharmaceutical ingredients belonging to different therapeuticcategories viz antiviral, anti-inflammatory, antidiabetic, antihypertensive, anti-convulsant, antibiotic,bronchodialator, antimalarial, antiemetic, antiamoebic, antipsychotic, antidepressant, anticancer, anticoagulant and sedative/hypnotic drugs and vitamins. Once the solid-state reactions of a pharmaceutical system are understood, the necessary steps can be taken to avoid reactivity and improve the stability of drug substances and products.