Crystallization Engineering in Aza-Steroid: Application in the Development of Finasteride

The study explored a novel crystallization method for purifying finasteride, a 5α-reductase inhibitor used for conditions like male pattern baldness. Traditional methods struggled to separate finasteride from its impurity, dihydrofinasteride, due to structural similarities. Researchers developed a technique using finasteride itself to purify the compound, reducing impurity levels from 3% to less than 0.2%. Additionally, a study on 10 male subjects with male pattern baldness showed that finasteride significantly reduced dihydrotestosterone (DHT) levels in the scalp without affecting testosterone levels, demonstrating its efficacy. However, the paper was retracted in 2016.