Liposomes coated with chitosan-xanthan gum (chitosomes) as potential carriers for pulmonary delivery of rifampicin

The aim of this work was to develop new microparticles for drug delivery to lungs by coating liposomes with chitosan (CH)xanthan gum (XG) polyelectrolyte complexes to obtain chitosomes. To this purpose, two groups of liposomes were prepared using a mixture of soy phosphatidylcholine and hydrogenated soy phosphatidylcholine in two different concentrations to evaluate their capability to entrap appropriate amounts of the model drug rifampicin. The obtained vesicles were then coated with different CHXG weight ratios and liposomes and chitosomes were characterized in terms of morphology, size, size distribution, zeta potential, drug entrapment, and rheological properties. The efficiency of chitosomes and liposomes during nebulization was also studied. Results of this study indicated that nebulization and rheological properties of chitosomes are affected by the CHXG weight ratio. In particular, CHXG 1:0.5 (w/w) coating was able to greatly improve drug total mass output and drug deposition in the lower stages of the impinger. (C) 2011 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 101:566575, 2012