N-acetyl-L-cysteine functionalized nanostructured lipid carrier for improving oral bioavailability of curcumin: preparation, in vitro and in vivo evaluations

The application of orally administered nanoparticles in the circulation system is limited by the secretion and shedding of intestinal tract mucous layer. In order to enhance mucoadhesion and mucus penetration of curcumin (Cur)-loaded nanostructured lipid carrier (NLC) after oral administration, a new multifunctional conjugate, N-acetyl-L-cysteine-polyethylene glycol (100)-monostearate (NAPG), was synthesized. Functionalized nanocarriers (Cur-NAPG-NLC) modified by different amounts of NAPG (the amounts of NAPG were 20, 50, and 100 mg) were prepared and investigated for in vitro and in vivo behavior. Mean particle sizes of 89–141 nm with negative zeta potential (−15 to −11 mV) and high encapsulation efficiency (EE, >90%) possessing spherical and stable nanocarriers were observed. Sustained drug release was also observed for the NAPG-NLC. In situ intestinal perfusion studies showed that with increasing the amount of NAPG increase absorption of Cur. In vivo oral pharmacokinetic evaluation suggested that the bioavailability of Cur in rats was proportional to the degree of functionalization of NLCs with NAPG. AUC(0–t) of Cur-NAPG100-NLC was improved by 499.45 and 116.89 folds as compared to that of Cur solution and unmodified Cur-NLC, respectively. In conclusion, NAPG modified NLC could be a promising drug delivery system for improving oral performance of BCS class IV drugs.