Bioavailability comparison of a new form of vilazodone XVII to IV in beagles using liquid chromatography/mass spectrometry

Vilazodone hydrochloride (CAS 163521-12-8) is polymorphic and has 15 crystal forms, referred to as I-XI and XIII-XVI. In the study, we prepared and performed structural identification of a new crystal form named XVII. To investigate this in vivo, a rapid and sensitive method based on liquid-liquid extraction, followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed and validated for the determination of vilazodone hydrochloride in dog plasma. This HPLC-MS/MS method was successfully applied to a bioavailability comparison of two crystal forms of vilazodone hydrochloride (IV and XVII) in six healthy beagles using a single-dose, two-way crossover design. The maximum plasma concentration (C_max), the time taken to reach C_max, and the area under the concentration-time curve were determined following oral administration of 10mg vilazodone hydrochloride (IV or XVII) to beagles. These analyses revealed no significant bioavailability differences between vilazodone hydrochloride forms IV and XVII in dogs.