Novel pulsed oxygen plasma mediated surface hydrophılizatıon of ritonavır for the enhancement of wettability and solubility

Abstract

The pulsed oxygen plasma treatment (POPT) of the ritonavir (RTV) powder/compacts was investigated as a novel possible physical technique for improving wettability, intrinsic dissolution rate (IDR), and, consequently, solubility of the poorly water-soluble RTV drug. Induction of POPT for 30 min enhanced 5.87-folds apparent solubility and 1.95-folds IDR at 24 h, attributed to RTV's surface hydrophilization. The POPT RTV exhibited zero contact angle compared to RTV suggesting improved wettability (untreated RTV = 74° and 30 min after POPT = 0°). The ATR-FTIR showed a broad peak of –OH group around 3300 cm -1, and XPS showed an increase in surface oxygen concentration from 9 % to 12 % aided through POPT lead to improved wettability of RTV. Moreover, the increased negative zeta potential was observed due to surface hydroxylation on the POPT RTV, resulting in increased surface polarity and RTV's solubility. It was found that there was no substantial thermal or physical alteration after POPT, as evident from DSC, SEM, and XRD studies. This study successfully demonstrated the impact of POPT on improvement in the wettability, solubility, and IDR of hydrophobic drugs RTV.