The Study Of PLGA Nanospheres Surface Modified With Biotinylated Chitosan As The Antitumor Drug Delivery Carriers

Nanospheres of biodegradable polymers can provide a way of sustained, controlled and targeted drug delivery to improve the therapeutic effects and reduce the side effects of the formulated drugs.Targeted drug delivery to cancer cells or tumor vasculature is an attractive approach to fight against cancer.In this study,biotin was introduced into a CS and the nanospheres were modified with bio-CS in an attempt to improve the design of nanospheres for an enhanced cancer targeting activity and intemalization into cancer cells.Epirubicin(EPI) loaded PLGA nanospheres were prepared by a solvent evaporation technique(W₁/O/W₂).The PLGA nanospheres surface was modified with CS by two strategies(adsorption and covalent binding).PLGA nanospheres of (248.4±21.0) nm in diameter characterized by the laser light scattering technique, scanning electron microscopy(SEM) are spherical and its drug encapsulation efficiency is(84.1±3.4)%.Zeta potential of unmodified nanospheres was measured to be negative -(21.21±2.13)mV.The positive zeta potential of modified nanospheres reveals the presence of CS on the surface of the modified nanospheres.Modified nanospheres were characterized for surface chemistry by X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FT-IR).FT-IR spectra exhibited peaks at 3420 cm^-1 and 1570 cm^-1,XPS spectra shows the N 1s(atomic orbital 1s of nitrogen) region of the surface of the nanospheres,corresponding to the primary amide of CS.In vitro drug release demonstrated that CS modified nanopheres have many advantages such as prolonged drug release property and decreased the burst release over the unmodified nanospheres, and the modified nanospheres by covalent binding method could achieve the release kinetics of a relatively constant release.Bio-CS were synthesized and characterized.The degree of substitution(DS),as defined as the number of biotin per 100 anhydroglucose units of CS,was determined by ¹H-NMR and ICP.Nanospheres were successfully prepared and modified with Bio-CS. The resulting formulations were characterized in terms of size,charge,morphology,drug encapsulation and drug release.Number of biotin molecules on nanoparticle surface was determined using a commercially available Quant^*Tag Biotin Kit.Hela cells were used for in vitro cytotoxicity evaluation of the PLGA nanospheres versus that Bio-CS modified nanospheres with the EPI concentration 150μg/mL for 4,24,48 and 72 h incubation.Bio-CS midofied nanospheres increased markedly anti-tumoral activity of EPI at concentrations of 50 mg/ml when compared to the non-targeted nanospheres.Flow cytometry and fluorescence microscope revealed that bio-CS modified nanospheres exhibited greater extent of cellular uptake than unmodified nanospheres and free EPI at 48h.To determine toxicity in vivo,mice were treated with nanospheres.No significant differences in clinical signs between the experimental group and the control group were found and no mortality occurred throughout the entire course of the study.Additionally, no significant differences in body weight between the two studied groups were observed. The aforementioned results indicated that no apparent toxicity to the studied animals was found after intravenous administration of the nanospheres prepared in the study.The in vivo pharmacokinetics was measured with male Wistar rats of 180-200g and 6-8 week old.The EPI loaded nanospheres can result much higher AUC and thus therapeutic effects of the drug than free EPI.Bio-CS modified nanospheres shows excellent sustained release properties both in vitro and in vivo.Bio-CS modified nanospheres were helpful for EPI to reach a long circulation time and were hopeful to be its novel drug carrier.Due to the advantage of surface modified nanospheres with Bio-CS,it may be useful in the delivery of anticancer drugs.