OBJECTIVE:To investigate the characteristics of drug release and the factors affecting the in vitro dissolubility of diclofenac potassium double-layer tablets(DPD).METHODS:UV-spectrophotometry and rotating basket method in the pha-rmacopeia of China 2000 edition were used to determine the in vitro dissolubility of DPD and Higuchi equation was adopeted to simulate the in vitro drug release.The main parameters of dissolution were stastistically analysed.RESULTS:Dissolution parameters of DPD were as follows:T0.3=0.10h,Td=3.30h,T0.9=9.19h.Hardness of tablets did not affect the dissolution rate significantly;pH of dissolution media significantly influenced on the rate.Rotation speed had a significant effect on dissolution action only at the beginning of test.CONCLUSION:DPD has good properties of fast and sustained release.Proper media is the key of in vitro drug release test,however,the ultimate results should be based on in vivo trial.

OBJECTIVE:To prepare temperature sensitive hydrogel which is of strength.METHODS:The hygrogel was prepared using CS,PVA and GP as matrix with concentration of CS(A),weight ratio of CS to PVA(B) and pH value(C) as factors and with initial gelatination temperature,strength and dehydration as indexes.The formula was optimized by orthogonal experiment and verified.RESULTS:The optimal formula was as follows:A 20 mg?mL-1,B 1 :1,C 7.2.The prepared hydrogel was fluid at 4 ℃ or room temperature while gelatinized at 37 ℃ within 10 min with strength of about 1.4 kPa.Gelatination time reduced along with the increase of temperature.The pH value had hardly changed during degradation in vitro within 28 d.CONCLUSION:The CS/PVA/GP hydrogel is simple and practical in preparation technique and is temperature sensitive and of strength.

Objective:To determine the equilibrium solubility and the apparent oil/water partition coefficient of nebivolol hydrochloride to provide experimental basis for the development of new preparations.Methods:The concentration of nebivolol hydrochloride was determined by an HPLC method,and a saturated solution method and a shake-flask method were respectively applied to determine the equilibrium solubility and the apparent oil/water partition coefficient of nebivolol hydrochloride in water,0.1 mol·L-1 HCl solution and phosphate buffer solution with different pH values(pH2.0,pH6.8,pH7.4 and pH8.0).Results:At (37±0.5)℃,the equilibrium solubility of nebivolol hydrochloride in water and in 0.1 mol·L-1 HCl solution was 722.53 μg·ml-1and 56.07μg·ml-1,respectively.The apparent oil/water partition coefficient (Log P) of nebivolol hydrochloride was 1.17 and 1.32,respectively.Within the pH range of 2.0-7.4,with the increase of pH value, the equilibrium solubility and the Log P decreased and increased,respectively,while pH value increased from 7.4 to 8.0,the equilibrium solubility of nebivolol hydrochloride increased and Log P decreased.Conclusion:The method is accurate and reliable.Nebivolol hydrochloride has poor water solubility,and the equilibrium solubility and the Log P are both influenced by pH values.

Objective:To establish a determination method for the content and entrapment efficiency of ropivacaine hydrochloride-loaded multivesicular liposomes. Methods: The separation of the multivesicular liposomes from the free drug was achieved by low-speed centrifugation. The concentration of ropivacaine hydrochloride in the supernatant and the multivesicular liposomes was determined by HPLC, and the entrapment efficiency was calculated. Results: The linear range of ropivacaine hydrochloride was 1. 0-80. 0μg· ml-1(r=0. 999 8). The average recovery was 99. 95% and RSD was 0. 72%(n=9). The content and entrapment efficiency of three batches of ropivacaine hydrochloride-loaded multivesicular liposomes was within the range of 99. 1%-100. 3% and 80. 06%-82. 14%, respectively. Conclusion:The method is simple and accurate, and can be used in the determination of content and entrapment efficien-cy of ropivacaine hydrochloride-loaded multivesicular liposomes.

Objective To investigate the relationship between plasminogen activator inhibitor(PAI) activity and coronary artery disease(CAD) in elderly patients. Methods Plasma samples from 93 patients with CAD were analyzed for the PAI activity, plasminogen activator(t-PA) activity, serum levels of cholesterol and triglyceride. The values of these parameters were compared between the CAD and the control groups. Results Higher plasma PAI activity 〔(810?360) AU/L vs. (640?300) AU/L,P

Objective:To optimize the formula of 5-aminosalicylic acid enema in situ gel. Methods:5-Aminosalicylic acid ene-mas in situ gel was prepared using a cold dissolution method with carbomer as the gel matrix and xanthan gum as the thickener. A 32 full factorial design was used to investigate the effects of the concentrations of carbomer and xanthan gum on the viscosity before and af-ter the gelling, duration of inversion tube and sedimentation rate. Response surface methodology was used to optimize the formula. Re-sults:The quantitative relationships between the two factors and the four evaluation indices were obtained. The optimum formula was as follows:the concentration of carbopol and xanthan gum in the enema was 0. 7% and 0. 15%, respectively. The viscosity before and af-ter the gelling was 500-1 000 mPa·s and 2 200-2 700 mPa·s, respectively. The duration of inversion tube test was 40-80 min and the sedimentation rate was more than 98. 5%. Conclusion:The multi-objective simultaneous optimization of the formula of 5-aminosal-icylic acid enema in situ gel is accomplished by factorial design and response surface methodology.

Magnetorheological fluid(MRF) is a sort of newly developed intelligent material.Because of the quick and adjustable magnetorheological effect of MRF,it is widely used in shock absorbers,clutches,polishing devices,hydraulic valves,etc.This paper mainly introduces magnetorheological fluid,magnetorheological effect,the work mode and characteristics of magnetorheological fluid shock absorbers as well as its application prospect in the wounded transport vehicle.

Since vibration highly influences the performance of vehicles, the effective improvment of vibration isolation has a great significance for enhancing the economy, balance, stability and reliability of vehicles. Based on the variable viscosity properties of magnetorheological(MR) fluids with the variation of a external magnetic flied resulted from adjustable and controllable electric current, a magnetorheological vibration isolator is developed. Through experiment and application, it is proved that the magnetorheological vibration isolator can highly increase vibration isolation efficiency.

Objective:To optimize the formula of ropivacaine hydrochloride transdermal gel. Methods:The steady transdermal rate and cumulative transdermal percentage in 24 h of ropivacaine hydrochloride gel were used as the indices, an orthogonal design was applied to select the optimal formula, and Design Expert 8. 0. 5. 0 software was used to analyze the results. Results: The optimal formula con-tained 2% carbomer, 10% propylene-glycol and 5% Azone. The steady transdermal rate of the optimal formula was 0. 6951 mg·h-1 · cm-2 . The cumulative transdermal percentage in 24 h of the optimal formula was 91. 04%, which was 22. 79% higher than that of ropiva-caine hydrochloride solution with the same concentration. Design Expert 8. 0. 5. 0 software could predict the steady transdermal rate and cumulative transdermal percentage in 24 h of the optimal formula. Conclusion: The preparation design is reasonable, and the gel has promising properties, which is suitable for skin local application.

Objective:To optimize the formula of amlexanox nasal thermosensitive gel spray and establish the quality control meth-od. Methods:Amlexanox nasal thermosensitive gel spray was prepared by a cold dissolving method, and poloxamer 407 (P407) and poloxamer 188 (P188) were used as the carrier materials. Central composite design-response surface methodology was used to optimize the formula with the amount of P407 and P188 as the influencing factors and the gel temperature and the viscosity before gelling as the indices. The content of amlexanox was determined by HPLC. According to Chinese Pharmacopoeia (2010 edition), the other indices of the preparation such as appearance, pH, viscosity, content, total spray times of each bottle and the content of each spray were deter-mined as well. Results:The optimum ratio of P407 and P188 was 17. 0% and 0. 9%,respectively . The average recovery of amlexanox was 98. 8% and RSD was 1. 7%(n=9). The quality of 3 batches of amlexanox nasal thermosensitive gel spray met the related require-ments. Conclusion:The formula and preparation process of amlexanox nasal thermosensitive gel spray are reasonable and feasible with controllable quality, which is worthy of further research.