[Study on the rifampicin polylactic acid microspheres for lung targeting].

In this paper, the effects of different variables on the preparation of polylactic acid microspheres (PLA-MS) were studied. The optimized preparation conditions of rifampicin polylactic acid microspheres (RFP-PLA-MS) were aquired through orthogonal test. The paddle method was used to study the drug release properties of RFP-PLA-MS. Stability of RFP-PLA-MS at different temperatures was also studied. Pharmacokinetic and tissue distribution of RFP-PLA-MS after intravenous administration were carried out in rabbits. The experiments revealed that the RFP-PLA-MS was regular in its morphology with a mean diameter of 9.00 +/- 4.08 microns. The drug loading was 16.0% and encapsulation efficiency was 31.9%. The release properties could be expressed by the following equation: Q = 20.77 + 10.12 T 1/2 (gamma = 0.9892). The RFP-PLA-MS was stable after stored at 4 degrees C and room temperature under desiccated condition for three months. RFP-PLA-MS showed a combination of lung targeting and sustained drug release in experiments on rabbits.