Transferrin-tailored solid lipid nanoparticles as vectors for site-specific delivery of temozolomide to brain

Blood–brain barrier restricts the uptake of many important hydrophilic drugs and limits their efficacy in the treatment of brain diseases because of the presence of tight junctions, high metabolic capacity, low pinocytic vesicular traffic, and efficient efflux mechanisms. In the present project, transferrin (Tf)-conjugated solid lipid nanoparticles (Tf-SLNs) were investigated for their ability to deliver temozolomide (TMZ) to the brain. SLNs were prepared by an ethanol injection method using hydrogenated soya phosphatidylcholine, triolein, cholesterol and distearoylphosphatidylethanolamine. Conjugation of SLNs with Tf was achieved by incubation of Tf with TMZ-loaded SLNs in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in phosphate buffered saline (pH 7.4) as a cross linker. SLNs preparation were characterized for particle size, polydispersity index, zeta potential, surface morphology, percent drug entrapment efficiency, in vitro drug release, and hemolytic toxicity studies. In vitro cytotoxicity studies were performed on human cancer cell lines. The average size was found to be 221 ± 3.22 nm with entrapment efficiency of 69.83 ± 2.52 and 249 ± 2.61 nm with entrapment efficiency decreased to 64.21 ± 2.27 % for unconjugated SLNs and Tf-SLNs, respectively. Fluorescence studies revealed the enhanced uptake of Tf-SLNs in brain tissue compared with unconjugated SLNs.