Effect of plasticizers on manufacturing ritonavir/copovidone solid dispersions via hot-melt extrusion: Preformulation, physicochemical characterization, and pharmacokinetics in rats

In this study, novel ritonavir solid dispersion (RTV SD) formulations were prepared with copovidone (PVPVA 64) and optimized plasticizers via hot-melt extrusion (HME) at different extrusion temperature to evaluate the effect of plasticizers on the process of HME. The optimized drug-loading content of RTV SD formulations was around 15% and RTV was converted to the amorphous state and integrated through physical interactions (possibly hydrogen bonding) with the polymeric carrier. Using Span 20 or HSPC as plasticizer, the HME extrusion temperature of RTV SD formulations suggested a decrease of 10 °C or 20 °C. Furthermore, the in vitro release and the in vivo pharmacokinetics analyses both showed that RTV SD formulations using Span 20 or HSPC as plasticizer possessed better release profiles and bioavailability over RTV bulk powder but showed equal physicochemical characteristics compared to RTV SD formulations without plasticizer. According to the increased drug solubility, enhanced dissolution profiles, superior bioavailability, but decreased extrusion temperature in HME process, the RTV SD formulation using HSPC as plasticizer could be potentially applied in the clinic as an efficient drug delivery system, and HSPC is recommended as an efficient plasticizer for manufacturing RTV SD formulations via HME.