International Journal of Nanomedicine (Mar 2016)
Enhanced dissolution and oral absorption of tacrolimus by supersaturable self-emulsifying drug delivery system
Abstract
Dae Ro Lee,1 Myoung Jin Ho,1 Hyuck Jun Jung,1 Ha Ra Cho,1 Jun Seo Park,1 Suk-Hyun Yoon,2 Yong Seok Choi,1 Young Wook Choi,3 Chung-Hun Oh,2,4,5 Myung Joo Kang1 1College of Pharmacy, 2Department of Medical Laser, Graduate School, Dankook University, Dongnam-gu, Choenan, Chungnam, 3College of Pharmacy, Chung-Ang University, Dongjak-gu, Seoul, 4Department of Oral Physiology, College of Dentistry, Dankook University, 5Abel Medi-Tech Inc., Dongnam-gu, Cheonan, Chungnam, Korea Abstract: A new Soluplus (polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer)-based supersaturable self-emulsifying drug delivery system (S-SEDDS) was formulated to enhance oral absorption of tacrolimus (FK506) with minimal use of oil, surfactant, and cosurfactant. A high payload supersaturable system (S-SEDDS) was prepared by incorporating Soluplus, as a precipitation inhibitor, to SEDDS consisting of Capmul MCM, Cremophor EL, and Transcutol (FK506:vehicle:Soluplus =1:15:1). In vitro dissolution profile and in vitro pharmacokinetic aspect of S-SEDDS in rats were comparatively evaluated with those of conventional SEDDS formulas containing four times greater content of vehicle components (FK506:vehicle =1:60). Both formulations formed spherical drug-loaded microemulsion <70 nm in size when in contact with aqueous medium. In an in vitro dissolution test in a nonsink condition, the amphiphilic polymer noticeably retarded drug precipitation and maintained >80% of accumulated dissolution rate for 24 hours, analogous to that from conventional SEDDS. Moreover, pharmacokinetic parameters of the maximum blood concentration and area under the curve from S-SEDDS formula in rats were not statistically different (P>0.05) than those of conventional SEDDS. The results suggest that the Soluplus-based supersaturable system can be an alternative to achieve a comparable in vitro dissolution profile and in vivo oral absorption with conventional SEDDS, with minimal use of vehicle ingredients. Keywords: tacrolimus, supersaturation, precipitation inhibitor, Soluplus, microemulsion, oral bioavailability