Micellar delivery of flutamide via milk protein nanovehicles enhances its anti-tumor efficacy in androgen-dependent prostate cancer rat model.

Purpose: This article describes the preparation, physicochemical characterization and in vivo assessment of parenteral colloidal formulation of flutamide (FLT) based on biocompatible casein (CAS) self-assembled micelles in order to control drug release, enhance its antitumor efficacy and reduce its hepatotoxicity.

Methods: Spray-drying technique was successfully utilized to obtain solidified redispersible drug-loaded micelles.

Results: Spherical core-shell micelles were obtained with a particle size below 100 nm and a negative zeta potential above -30 mV exhibiting a sustained drug release up to 5 days. After intravenous administration into prostate cancer bearing rats for 28 days, FLT-loaded CAS micelles showed a higher antitumor efficacy as revealed by significantly higher reduction in PSA serum level (65.95%) compared to free FLT (55.43%). Moreover, micellar FLT demonstrated a marked decrease in relative weights of both prostate tumor and seminal vesicle (34.62 and 24.59%) compared to free FLT (11.86 and 17.74%), respectively. These antitumor responses were associated with notable reduction of cell proliferation, intratumoral angiogenesis and marked increase of tumor apoptosis. A significantly lower risk of hepatotoxicity was observed by micellar FLT as evidenced by lower alanine aminotransferase (ALT) serum level compared to free FLT.

Conclusions: Overall this approach suggested that CAS micelles might be an ideal candidate for intravenous delivery of hydrophobic anticancer drugs.