Core-shell nanoparticulate formulation of gemcitabine: lyophilization, stability studies, and in vivo evaluation.

Abstract

Core-shell nanoparticulate formulation of gemcitabine was prepared by incorporating gemcitabine in a hydrophilic bovine serum albumin (BSA) core surrounded by hydrophobic poly(DL-lactic acid-co-glycolic acid) (PLGA) shell with a particle size of 243nm and encapsulation efficiency of 40.5%. Prepared formulations were lyophilized, wherein several cryoprotectants were screened for product attributes such as cake appearance, reconstitution with water, and size constancy. Trehalose was screened as a lyoprotectant, which showed stability for 6months at 5°C and 25°C/60% relative humidity (RH) conditions. However, an increase in particle size was observed at accelerated conditions (40°C/75% RH). In vitro evaluation of these nano-formulations in MCF-7 breast cancer cells showed enhanced cellular uptake (90%) as compared to GEMCITE® uptake (51%) in 6h along with reduced IC50 value at 72h (16μM versus 30μM). In vivo studies in Sprague Dawley rats showed C max, t 1/2, and area under the curve (AUC) at 2.55μg/ml, 13.6h, and 28,322.5μg/l/h, respectively, whereas GEMCITE® at the same dose showed significantly lower corresponding values at 1.94μg/ml, 6.89h, and 13,967μg/l/h. In the same study, AUC and C max of inactive metabolite of gemcitabine (dFdU) were reduced by 33 and 42%, respectively, for these nanoparticles compared to GEMCITE®. In 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast cancer model, significantly reduced tumor growth was observed in gemcitabine-loaded-nanoparticle-treated animals compared with GEMCITE®-treated animal at equivalent dose (121 versus 243% in 30days). The results indicated that our core-shell nanoparticles are more effective for tumor reduction compared to marketed formulation ofgemcitabine, GEMCITE®.