Design of Nanocrystalline Suspension of Dutasteride for Intramuscular Prolonged Delivery

The study successfully formulated an injectable nanocrystalline suspension of dutasteride (DTS) for prolonged intramuscular delivery, aimed at treating benign prostatic hyperplasia and scalp hair loss. The optimized suspension, with a particle size of 324 nm and a zeta potential of −11 mV, demonstrated a sustained drug release profile, achieving peak concentration after 8.40 days and an elimination half-life of 9.94 days in rats. Although a granulomatous inflammatory response was observed at the injection site 7 days post-administration, it significantly decreased by day 14 and was minimal by day 28. These results indicate that the nanosuspension system is effective for sustained DTS delivery with manageable local inflammation.