Studies on the cyclosporin A loaded stearic acid nanoparticles

Stearic acid nanoparticles were prepared in this study by melt-homogenizati on to investigate the possibility of them as a new kind of drug carrier sys tem. Some physicochemical properties of stearic acid nanoparticles were stu died and morphology examined by transmission electron microscope. Cyclospor in A as a model drug was then encapsulated into stearic acid nanoparticles. Following the establishment of high performance liquid chromatography assa y for cyclosporin A analysis in stearic acid nanoparticles or blood samples , the encapsulation ratio of cyclosporin A to stearic acid nanoparticles wa s estimated and pharmacokinetics as well as bioavailability of cyclosporin A stearic acid nanoparticles after oral administration to Wistar rats were studied, using the Sandimmun Neoral(R) (an available microemulsion system o f cyclosporin A) as a reference. The mean diameter of cyclosporin A stearic acid nanoparticles was 316.1 nm, while the encapsulation ratio of cyclospo rin A to stearic acid nanoparticles reached to 88.36%. It was demonstrated by 1R spectra and differential scanning calorimetry that there was no chemi cal reaction occurred between the cyclosporin A and stearic acid. The relat ive bioavailability of cyclosporin A stearic acid nanoparticles over refere nce was nearly 80%, and the time to reach maximum concentration (T-max) of cyclosporin A after oral administration of cyclosporin A stearic acid nanop articles was delayed significantly than the reference, suggesting an obviou s sustained release effect. The stearic acid nanoparticles might be a very potential drug carrier. (C) 2000 Published by Elsevier Science B.V. All rig hts reserved.