Preparation of Carboxymethyl Chitosan Nanospheres via its Crosslinking of in an Inverse Microemulsion System as Carrier for Amphotericin B Delivery

Natural biopolymers or their semi-synthetic derivatives are widely interested for drug or gene delivery applications. Carboxymethyl chitosan (CMCS) as a smi-synthetic biopolymer is nontoxic, biocompatible, biodegradable and mucoadhesive; it has well-known macrophage activation property which renders it highly useful for drug delivery to macrophages. Here, fabrication of biodegradable CMCS nanospheres will be reported using an inverse microemulsion technique to provide particles of controlable size; and its distribution and morphology. Microemulsions were prepared by dispersion of CMCS aqueous acidic solutions (using acetic acid) in n-hexane continuous phase. AOT and glutaraldehyde were used as an emulsifier and a crosslinking agent, respectively. Virgin CMCS and the resulting nanospheres were throughly characaterized using spectroscopic (FTIR spectroscopy) and micropscopic (SEM) methods to study the cross-linking reaction mechanism and particle size and morphology, respectively. The obtained particle perfectly spherical in the range of 100-300 nm diameter with a narrow size distribution according to the SEMs. Crosslinking of CMCS was confirmed in FTIR spectra by appearance of signal bands at 2889 cm-1 which represent the stretching vibration of C=N bond. During a series of experiments the concentration of the CMCS, the concentration of the AOT and the concentration of the glutaraldehyde were varied according to a plan obtained by four factorial three levels experimental design. The depending variable was the mean size of the CMCS nanospheres. After evaluating the result of the experiments it was found that the concentration of AOT had significant influence on the particle size, while surprisingly the concentration of the glutaraldehyde had only non significant, minor effect. The obtained nanospheres were used for Amphotericin B delivery.