ABSTRACT
The influence of chiral excipient D-chitosan (CS) on the stereoselective release of racemic ketoprofen (rac-KET) microspheres has been investigated in comparison to those microspheres containing individual enantiomers in vitro and in vivo. Stereoselectivity was observed in vitro release test, with R-KET release slightly higher than that of S-KET, especially in 3% rac-KET loading microspheres. Stereoselectivity is dependent on the content of chiral excipient and pH of release medium. A molecular docking study between CS and KET enantiomers further revealed that S-KET has a stronger interaction with CS compared to R-KET. Moreover, the plasma concentration of KET enantiomers in rats shows substantial differences, as the plasma levels of S-KET were higher than those of R-KET. Plasma levels of enantiomers from the R-KET microspheres had similar stereoselectivity as rac-KET microspheres. The S/R ratio of rac-KET microspheres was significantly lower than that of rac-KET suspension (regular-release formulation) (p<.05), and the differences is 3-5 fold. Besides, rates of R-KET converted to S-KET exhibited differences between rac-KET microspheres and suspension. Similar results were also found between R-KET microspheres and suspension. All investigations suggest that the chitosan interacting preferentially with S-KET to R-KET significantly affect the stereoselective pharmacokinetics of rac-KET from chitosan microspheres in rats.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Chitosan/administration & dosage , Drug Delivery Systems/methods , Ketoprofen/administration & dosage , Microspheres , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/metabolism , Chitosan/chemistry , Chitosan/metabolism , Drug Evaluation, Preclinical/methods , Female , Ketoprofen/chemistry , Ketoprofen/metabolism , Male , Molecular Docking Simulation/methods , Rats , Rats, Sprague-Dawley , StereoisomerismABSTRACT
OBJECTIVE: To study the therapeutic effect of Dabuyin Wan on true precocious puberty of female rats and its possible mechanism. METHOD: Twenty-two-day-old female SD rats were subcutaneously injected with 40 mg x kg(-1) N-methyl-DL-aspartic acid (NMA) at 14:00 and 16:00 every day; meanwhile, the rats were given Dabuyin Wan for intervention. Visual inspection was conducted for the time of vaginal opening. The first estrus was observed by yaginal smear test. Their ovaries and uterus were weighed to calculate organ coefficients. Conventional pathological slices were made to observe morphological changes in ovaries and uterus and calculate the thickness of uterine walls and the number of corpus luteums. The level of E2 in serum was detected to assess the therapeutic effect of Dabuyin Wan on NMA precocious puberty in rats. expressions of GnRH, GPR54 and Kiss-1 mRNA in hypothalamus were measured by semi-quantitative RT-PCR to investigate the possible mechanism of Dabuyin Wan. RESULT: Dabuyin Wan at 3.24 g x kg(-1) and 1.62 g x kg(-1) significantly decreased the organ coefficients in rats with precocious puberty (P < 0.05), decrease the number of vaginal openings in rats (P < 0.01) and the thickness of uterine walls and the number of corpus luteums (P < 0.05), and notably down-regulated expressions of GnRH, GPR54 and Kiss-1 mRNA in hypothalamus (P < 0.05), without significant impact on E2 in serum. CONCLUSION: Dabuyin Wan may inhibit GnRH synthesis and release as well as startup of hypothalamic-pituitary-gonadal axis by down-regulating Kiss-1/GPR54 mRNA expression in hypothalamus, in order to realize the therapeutic effect on true precocious puberty.