Ammonium methacrylate units polymer content and their effect on acyclovir colloidal nanoparticles properties and bioavailability in human volunteers

Acyclovir (ACV)-Eudragit (EUD) nanoparticles (NPs) were prepared using both EUD RS 100 and RL 100 with different charge density. The effect of charge intensity on particle size, encapsulation efficiency, and in vitro dissolution was assessed. The bioavailability of ACV NP colloids were evaluated in human volunteers, compared with commercial product using a validated LC–MS/MS method with a lower limit of quantification (LLOQ) of 0.02 μg/ml. EUD RL 100 with higher ammonium groups gave smaller NPs than EUD RS 100. The surface charge of the polymer did not affect encapsulation efficiency and in vitro dissolution. In human volunteers, both F2 and F5 colloidal nanosuspensions prepared with EUD RS and RL respectively in drug to polymer ratio 1:3 sustained the oral absorption of ACV, expressed by the significant lower Cmax, significant delayed Tmax and the significant higher HVDt 50%CmaxHVDt 50%Cmax. The mean Cmax of F2, F5, and Zovirax® were 0.61 ± 0.06, 0.73 ± 0.07 and 0.92 ± 0.21 μg/ml respectively. Furthermore, the AUC0–12 of F2 and F5 was significantly higher than that of Zovirax® with values of 4.37 ± 0.88, 5.14 ± 0.87 and 3.21 ± 0.53 μg/ml h respectively. The higher AUC0–12 for both F2 and F5 reflected high relative bioavailability of 136.2% and 159.9% respectively compared to commercial ACV tablets.