Preparation and controlled release of colon-targeted carboxymethylchitosan microspheres containing l

Objective:To prepare levofloxacin-carboxymethyl-chitosan(LVFX/CMC) microspheres and to study their colon-targeted release in rats.Methods: KromasilRKR100-5C18(250 mm×4.6 mm)was used as the analytical column and the temperature was maintained at 50℃.The mobile phase consisted of a mixture of acetonitrile:0.1% trifluoroacetic acid(2080) pumped at a flow rate of 1.0 ml/min,with λ_(ex)295 nm and λ_(em)495 nm.Sixty healthy male SD rats were randomized into 2 groups: to receive gastric lavage with normal LVFX(40 mg,control group) and LVFX/CMC microspheres(40 mg,treatment group).HPLC was used to detect the concentrations of LVFX in the stomach,intestine,cecum,colon and blood in rats in both groups.Results: LVFX was detectable 3 h after LVFX/CMC microsphere lavage.Five hours after lavage,the levels of LVFX in cecum and colon were respectively(3.394±0.197) mg and(1.873±0.216) mg in treatment group,and(0.489±0.123) mg and((0.078±0.002)) mg in control group(P<0.01).Nine hours after lavage,the levels of LVFX in cecum and colon were((1.580±)(0.234)) mg and(0.713±0.073) mg in treatment group,and(0.105±0.023) mg and(0.054±0.016) mg in control group(P<0.01),respectively.Serum level of LVFX peaked at 5 h in treatment group and at 1 h in control group.The concentrations of LVFX were obviously higher in cecum and colon than those in stomach and intestine.Conclusion: The prepared LVFX/CMC microspheres have the property of colon-targeted release in rats.