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Objective To prepare asiatic acid (AA) loaded chitosan-deoxycholic acid self-assembled micelles (AA-CS-DCA PMs) adopting chitosan-deoxycholic acid (CS-DCA) as carriers and investigate its pharmacokinetic characteristics in rats. Methods AA-CS-DCA PMs were prepared by ultrasonic dispersion method. The characteristics of micelles were evaluated by the distribution of particle size, Zeta potential, drug loading, encapsulation efficiency, and in vitro release. Model of bile drainage was established in conscious rats and pre-column derivatization HPLC method was used to determine the concentration of AA in bile. Moreover, the pharmacokinetics characteristics of AA-CS-DCA PMs in vivo was evaluated by tmax, Cmax and AUC0-t. Results The particle size was (70.5 ± 9.8) nm, the Zeta potential was (38.4 ± 0.8) mV, and encapsulation efficiency and drug loading were (77.8 ± 1.2)% and (11.7 ± 0.2)%, respectively. The in vitro release profile showed a sustained release property. In vivo study showed that Cmax of AA-CS-DCA group (26.05 ± 3.04) μg/h was 2.8 times higher than that of the control group (9.19 ± 1.12) μg/h; The tmax of AA-CS-DCA PMs group prolonged significantly (P < 0.05) in biliary excretion (2 h vs 1 h) and the elimination half-life t1/2 was 1.8 times of the control group [(2.68 ± 1.71) h vs (1.49 ± 0.38 h)]. In addition, the AUC0-24 h which reflected the degree of drug absorption increased by 200% compared with the control group [(99.05 ± 12.83) μg vs (33.56 ± 8.33) μg]. Conclusion The chitosan- deoxycholic acid self-assembled micelles can raise the concentration of AA and prolong the retention time in vivo, which effectively improve the oral bioavailability of AA.
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Objective: To determine the prescription technology of gastrodin starch microsphere and investigate its nasal mucoadhesion and in vitro release characteristics. Methods: Gastrodin starch microspheres were prepared by compound emulsion crosslinking method. According to the particle diameter, drug loading efficiency (DLE), and entrapment efficiency (EE), the best prescription technology was selected by using single-factor investigation and uniform design. Using toad palate mucosa as model and average residence time as indicator, mucoadhesion of gastrodin starch microsphere was evaluated. Using gastrodin API as a control, paddle method was applied to in vitro release test of gastrodin starch microspheres. The content of gastrodin was determined to calculate the cumulative release percentage. In addition, the curve of drug release in vitro was fitted with different release model to analyze the in vitro release characteristics of gastrodin starch microsphere in nasal cavity, synthetically. Results: The optimum prescription and preparation technology of gastrodin starch microsphere were as follows: gastrodin 2.0 g, starch 4.5 g, liquid paraffin 100.0 mL, Span80 3.5 g, ECH 5.1 mL, preparation temperature 40℃, and rotational speed 1000 r/min. The particle diameter of gastrodin starch microsphere was (47.69±1.92) μm, the DLE and EE of microsphere were (9.78±0.70)% and (35.72±3.28)%, respectively. It was about (176.92±23.25) s that in adhesive powder resided in nasal cavity, which translated into human nasal residence time was just 20-30 min, while the average residence time of gastrodin starch microspheres was extended to (944.33±68.29) s, translated into human nasal residence time was about 3 h. The cumulated release percent of gastrodin starch microspheres was more than 90% in 3 h. Compared with other in vitro release models, Weibull model was the fittest model to gastrodin starch microspheres, the t50 of gastrodin starch microspheres was 40.08 min, and t90 was 245.73 min. Conclusion: Gastrodin starch microspheres prepared with optimum prescription technology have uniform particle diameter, high DLE and EE. Microspheres have good mucoadhesion and sustained release, ensure that gastrodin release gently and completely during the nasal retention period.
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OBJECTIVE:To prepare aspirin gastric floating capsule and to study its in vitro drug-release characteristics.METHODS:Aspirin gastric floating capsule was prepared with aspirin as model drug,and with hydroxypropyl methylcellulose(HPMC)under different viscosity and different quantity and carbopol as main excipients.The release rate of the capsules was determined.RESULTS:When the optimal ratio between HPMC K4M and HPMC K15M was3to1,then the in vitro drug release of aspirin gastric floating capsule within0h～10h conformed to apparent zero-order kinetics with rate constant Kr at10.3%/h and release parameter at0.6173.CONCLUSIONS:The prepared capsule has a marked slow-release effect,the quantity and the viscosity of HPMC were the main factors affecting the release rate of gastric floating capsule,the in vitro drug release characteristics were associated with the joint action of bulk erosion and drug diffusion.