Identification and characterization of major degradation products of risperidone in bulk drug and pharmaceutical dosage forms.

Acid, base and oxygen stability of risperidone, a novel anti-psychotic drug, has been evaluated storing the sample in solution phase. One of the major degradation products has been identified and characterized by using techniques namely IR, MS and NMR after isolation by preparative LC. The other major degradation product has been identified with help of MS/MS data and by co-eluting in analytical LC with the available standard. The effect of acid and base resulted in the formation of hydroxy risperidone and the effect of oxygen lead to the formation of N-oxide of risperidone. The two major degradation products in the dosage forms were also characterized as 9-hydroxy risperidone and N-oxide of risperidone, after enrichment through preparative LC, by LC-MS/MS and HPLC. Structural elucidation of degradation product leading to the formation of N-oxide of risperidone is discussed in detail.