OBJECTIVE To investigate the absorption and distribution of
chitosan capsule filled with
dexamethasone sodium phosphate (DSP)
liposome lyophilized powder in rats.METHODS DSP liposome was prepared by duplicated emulsification method. Its formula was determined with the orthogonal experiment. The quality of DSP liposome, such as the encapsulation rate, drug-loading, morphology and size distribution, was estimated. The chosen liposome, made into its lyophilized powder, was then filled into the capsule coated with HPMCP.The capsules as well as the other DSP dosage forms were administered orally. Blood and colon tissue were collected periodically. The concentration of DSP was measured by HPLC, and used to calculate the relative targeting drug delivery index(DDI) of DSP.RESULTS The prepared DSP liposome was characterized by its average encapsulation rate of 54.82%, drug-loading of 8.67%, and the size distribution from 120 nm to 265 nm(averaged 178 nm). After oral administration, the blood level of DSP lyophilized liposome capsule was the lowest in all the DSP dosage forms, but the distribution of DSP in colon was the highest. The relative targeting DDI of DSP lyophilized liposome capsule was 29.18 or 2.28, against DSP solution or DSP powder capsule, respectively.CONCLUSION DSP lyophilized liposome
chitosan capsule may be more helpful in treating colitis than DSP powder chitosan capsule. Hence, it is worth studying further.