Evaluation of Caco-2 cell permeability of ritonavir nanosuspensions

Abstract

Background and Aims: Poor aqueous solubility limits drug absorption through intestinal mucosa. Nanosuspensions with nanometer range particle size provides enhanced aqueous solubility and hence permeability. The objective of this study was to investigate the cytotoxicity and in vitro cell permeability through human adenocarcinoma (Caco-2) cells of ritonavir (RTV) nanosuspensions. Methods: The Microfluidization method was used to prepare nanosuspensions. Particle size (PS), polydispersity index (PI) and zeta potential (ZP) values were measured as characterization. MTT test was applied to evaluate the cytotoxic effect. Caco-2 cell lines were used for transport studies with RTV coarse powder, physical mixtures and nanosuspension. Results: Approximately 600 nm PS, 0.4 PDI and 22 mV ZP values were observed for nanosuspensions. The sample groups showed no cytotoxicity on the cell lines in any RTV concentration. However, significant cytotoxic effect was determined in groups with high amounts of sodium dodecyl sulfate. The transported RTV in nanosuspension formulation enhanced by 5.3- fold and 1.5-fold in comparison with RTV coarse powder and physical mixture, respectively. Rate of the transportation and also the amount of the transported RTV were improved with nanosuspension formulation. Conclusion: Particle size reduction of RTV into nanometer size and preparing nanosuspension system was found effective to obtain enhanced cell permeability.