Lipomers (Lipid-polymer Hybrid Particles) of Vardenafil Hydrochloride: a Promising Dual Platform for Modifying the Drug Release Rate and Enhancing Its Oral Bioavailability.

Vardenafil hydrochloride is commonly used for the curing of erectile dysfunction. VAR suffers certain limitations: (i) short elimination half-life (4-5 h), (ii) low aqueous solubility (0.11 mg/mL), (iii) susceptibility to extensive first-pass metabolism and drug efflux transporters (P-glycoprotein), and (iv) limited (15%) oral bioavailability. The current study focused on the development of VAR lipomers as promising modified release systems able to enhance oral bioavailability. VAR-lipomers (lipid-polymer complexes) were successfully developed by a modified precipitation technique employing a lipid (polyglyceryl-6-distearate or glyceryl tristearate) and an amphiphilic polymer (Gantrez®). Three VAR:lipid ratios [1:1, 1:2, and 1:3] and three VAR:Gantrez® ratios [4:1, 2:1, and 1:1] were investigated. Solid-state characterization studies involved differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy. The systems were assessed for particle size, polydispersity index (PDI), zeta-potential, VAR entrapment-efficiency (EE%), morphology, and VAR released % after 2 h (Q2h) and 8 h (Q8h). The best-achieved system (the highest desirability) was promoted for pharmacokinetic studies in fasted rabbits. Statistical analysis of data revealed that L9 system (PGDS, VAR, and Gantrez®; 3:1:1, respectively) had the highest desirability (0.85) with respect to spherical particle size (622.15 nm), PDI (0.11), zeta-potential (-27.90 mV), EE% (62.80%), Q2h (43.45%), and Q8h (77.40%). With respect to Levitra® tablets, the significantly higher relative bioavailability (170%), delayed Tmax, and extended MRT(0-∞) clarified the dual ability of L9 system. Lipomers are emerging systems capable of modifying the rate of VAR release and promoting its oral bioavailability.