Pharmacokinetic control of orally dosed cyclosporine A with mucosal drug delivery system

Abstract

This study aimed to control the oral absorption of cyclosporine A (CsA) with the use of a mucosal drug delivery system (mDDS). Mucopenetrating nanocarriers (MP/NCs) and mucoadhesive nanocarriers (MA/NCs) were prepared by flash nanoprecipitation employing polystyrene-block-poly(ethylene glycol) and polystyrene-block-poly(N,N-dimethyl aminoethyl methacrylate), respectively. Their particle distribution in the rat gastrointestinal tract were visualized by fluorescent imaging. Plasma concentrations were monitored after oral administration of CsA-loaded MP/NCs (MP/CsA) and MA/NCs (MA/CsA) to rats. MP/NCs and MA/NCs had a particle size below 200 nm and ζ-potentials of 4 and 40 mV, respectively. The results from in vitro experiments demonstrated mucopenetration of MP/NCs and mucoadhesion of MA/NCs. Confocal laser scanning microscopic images showed diffusion of MP/NCs in the gastrointestinal mucus towards epithelial cells and localization of MA/NCs on the surface of the gastrointestinal mucus layer. In a pH 6.8 solution, rapid and sustained release of CsA were observed for MP/CsA and MA/CsA, respectively. After oral dosing (10 mg-CsA/kg) to rats, amorphous CsA powder exhibited a time to maximum plasma concentration (T_max) of 3.4 h, maximum plasma concentration (C_max) of 0.12 μg/mL, and bioavailability of 0.7%. Compared with amorphous CsA powder, MP/CsA shortened T_max by 1.1 to 2.3 h and increased the bioavailability by 43-fold to 30.1%, while MA/CsA prolonged T_max by 3.4 to 6.8 h with C_max and bioavailability of 0.65 μg/mL and 11.7%, respectively. These pharmacokinetic behaviors would be explained by their diffusion and release properties modulated by polymeric surface modification. The mDDS approach is a promising strategy for the pharmacokinetic control of orally administered CsA.