Qualitative study for finasteride detection in the prostate delivered by reversible inhibition of sperm under guidance – Prostate hair (RISUG-PH^™) vas injectable implant

Objectives Drug delivery to the prostate through the conventional route is associated with pharmacokinetics-based and drug-related side effects. Finasteride (FIN) is the model drug used clinically for the management of prostate hyperplasia through the oral route. An alternate localized drug delivery route is a prerequisite that may offer many advantages over the oral route of drug delivery to the prostate. The present study confirms the hypothesis of using vas deferens, a localized drug delivery route to the prostate using an injectable drug delivery implant, that is, Reversible Inhibition of Sperm Under Guidance – Prostate Hair (RISUG-PH ™ ). Material and Methods We developed a styrene maleic anhydride, FIN, and dimethyl sulfoxide-based injectable implant that was biophysically characterized using Fourier transform infrared (FTIR) and powder X-ray diffraction (PXRD). Fluorescence microscopy and atomic force microscopy (AFM) were used to characterize the implant. Matrix-assisted laser desorption ionization–time of flight (MALDI-ToF/ToF) and high-resolution mass spectrometry (HRMS) were used to confirm the presence of FIN in the prostate of the implant-injected rats. Results FTIR and powder-XRD confirmed the amorphous nature of the implant. Fluorescence microscopy and AFM confirmed the in vivo generation of sub-micron-sized particles, which may act as a drug carrier forming from the implant. Finally, using MALDI-ToF/ToF and HRMS, the presence of FIN was confirmed in the ventral prostate of male rats by identifying the m/z ratio corresponding to the production of molecular FIN and confirming the elemental composition of the detected [M+H]+ precursor ion with standard FIN within an acceptable limit of actual mass error of −7.2 ppm versus +3.5 ppm of standard FIN, respectively. FIN was also detected in the prostate after a period of 28 days post 1-time implant injection in the lumen of vas deferens of the male rats. It showed a better signal intensity detection of FIN compared to the oral route. Conclusion This study confirmed that RISUG-PH ™ delivers FIN to the prostate on single implantation in male rats, confirming the use of vas deferens as a localized route for drug delivery to the prostate.