Design and characterisation of an amorphous formulation of nifedipine for the treatment of autonomic dysreflexia

Abstract Objectives Current treatment for autonomic dysreflexia (AD) involves rupturing a liquid-filled soft capsule of nifedipine to aid rapid drug release and absorption, however, this application is not covered under the manufacturer's license. The objective of the current work was to design a rapidly dissolving solid dosage formulation for the treatment of AD as an alternative to the off-license “bite and swallow” use of currently available commercial products. Methods Amorphous solid dispersions (ASDs) of nifedipine were prepared by spray-drying using three different polymers: hydroxypropyl methyl cellulose (HPMC), polyvinyl pyrrolidone (PVP) and polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol (Soluplus), at a 15% w/w drug loading and were formulated and compressed into tablets. Dissolution testing was performed in the paddle dissolution apparatus using either a monophasic or biphasic medium. Key findings The PVP–nifedipine ASD tablets exhibited rapid dissolution, with 35% of the total nifedipine dose dissolving within 15 min in the monophasic dissolution medium. The HPMC–nifedipine ASD exhibited a very slow dissolution, while the Solupus–nifedipine system exhibited no nifedipine release over 120 min. When tested in the biphasic dissolution medium, the PVP–nifedipine ASD tablets exhibited a release profile comparable to that of the pre-split/ruptured nifedipine soft capsule product. Conclusions This study demonstrates that a nifedipine–PVP ASD is a promising formulation strategy in the treatment of AD.