What type of incompatibility results from molecular changes in drugs?

Chemical incompatibility occurs when molecular changes in the drugs lead to alterations in their structure and properties. This can result in reduced efficacy or the formation of harmful byproducts. For instance, when two drugs are mixed, one may chemically react with the other, potentially creating a precipitate or degrading the active ingredients. Such reactions can happen due to various factors including pH changes, oxidation, or hydrolysis.

On the contrary, physical incompatibility typically involves changes in appearance or solubility but does not alter the drug on a molecular level. Therapeutic incompatibility refers to instances where the combined drugs negatively affect the therapeutic outcome without necessarily changing the chemical structure. Thermal incompatibility involves the effects of temperature on drug stability but does not directly address molecular changes. Therefore, chemical incompatibility is the correct identification of incompatibility resulting from changes at the molecular level.