Formulation optimization of ginkgo flavonoids matrix tablets by orthogonal design / 中国中药杂志

Sustained-release tablet has become one of the hottest research spots in the area of sustained release preparations with its unique advantages. At present, a series of shortcomings were exited in the ordinary ginkgo preparations, which were used for the treatment of cardiovascular and cerebrovascular diseases. In order to avoid these shortcomings, ginkgo flavonoids matrix tablets were prepared in this paper. Furthermore, the amount and varieties of matrix material, adhesives and fillers were investigated. Meanwhile, the formulation was optimized by using the method of orthogonal design, and Zero-order, First-order, Higuchi, Ritger-peppas equation were used for the model fitting and mechanism discussing of drug release.

Preparation of valsartan nanosuspensions and its in vitro dissolution / 药学学报

To increase the dissolution rate and extent of valsartan, valsartan nanosuspensions have been prepared. Controlled precipitation assisted with sonication is utilized to prepare valsartan nanosuspensions, the concentration of the drug, stabilizer and costablizer had a great effect on the stability of the preparation according to the pre-experiment. So the method of central composite design-response surface is used to optimize the prescription based on the above three factors and the particle size as the response value. The software Origin 8.0 is used to draw the view of the three-dimensional effects and 2D contour map, to get the optimal prescription area. Valsartan nanosuspensions were prepared. The mean diameter and zeta potential are about 216.6 nm and -57.7 mV, respectively. Compared with the microsuspensions and commercial preparation, the dissolution of valsartan nanosuspensions was faster and the bioavailability can be enhanced to some extent.

Intestinal absorption kinetics of flurbiprofen in rats / 药学学报

To study the in situ intestinal absorption kinetics of flrubiprofen in rats, the absorption of flurbiprofen in small intestine (duodenum, jejunum and ileum) and colon of rats was investigated using in situ single-pass perfusion method and the drug content was measured by HPLC. The effects of drug concentration on the intestinal absorption were investigated. The K(a) and P(app) values of flurbiprofen in the small intestine and colon had no significant difference (P > 0.05). Drug concentration (4.0, 10.0 and 16.0 mg x L(-1)) had no significant influence on the K(a) values (P > 0.05). However, when concentration was 4.0 mg x L(-1) and 10.0 mg x L(-1), significant effect on the P(app) values (P < 0.05) was found, but significant effect on the P(app) values was not shown between 10.0 mg x L(-1) and 16.0 mg x L(-1) (P > 0.05). The K(a) and P(app) values of flurbiprofen on the perfusion flow rate had significant difference (P < 0.05). Flurbiprofen could be absorbed at all segments of the intestine in rats and had no special absorption window. The absorption of flurbiprofen complies with the facilitated diffusion in the general intestinal segments, and accompany with the cytopsistransport mechanism probably. The perfusion flow rate had significant effect on the K(a) and P(app).

Preparation of PEG-modified nanostructured lipid carriers loaded with hydroxycamptothecin and tissue distribution in mice / 药学学报

Hydroxycamptothecin (HCPT) loaded PEG modified nanostructured lipid carriers (HCPT-PEG-NLC) and nanostructured lipid carriers (HCPT-NLC) were prepared by melt emulsification and homogenization method. The morphology, particle size and encapsulation efficiency of them were investigated. HCPT concentrations in plasma, heart, liver, spleen, lung, kidney and ovary were determined after iv of HCPT injection, HCPT-PEG-NLC and HCPT-NLC in mice. The targeting indexes of HCPT-PEG-NLC and HCPT-NLC were calculated. The transmission electron microscope imaging showed that HCPT-PEG-NLC and HCPT-NLC exhibited a spherical shape. The particle sizes of them were (88.6 +/- 22.5) and (127.2 +/- 43.4) nm. The encapsulation efficiency were (90.51 +/- 3.29)% and (84.37 +/- 2.81)%, respectively. After iv injection into the tail vein of mice, HCPT plasma concentrations of HCPT-PEG-NLC and HCPT-NLC were higher than that of HCPT injection at each sampling time. They also showed longer elimination time in every tissue. HCPT-NLC accumulated in endothelial system (RES), Re and Ce of it in liver and spleen were significantly higher than HCPT-PEG-NLC. HPCT-PEG-NLC prolonged circulation time and increased bioavailability of HCPT. MRT and AUC0-24 h of it were 19.80 and 17.02 times higher than those of HCPT injection. It also significantly reduced phagocytosis of RES, and showed lung targeting effect (Re and Ce were 14.51 and 41.35). To summarize, HCPT-PEG-NLC could prolong the circulation time of HCPT in vivo, and had the lung targeting effect. It was a promising carrier to increase therapeutic effect of HCPT in treating lung cancer.

Optimization of a novel mucoadhesive drug deliver system with ion-exchange resin core loaded with berberine hydrochloride using central composite design methodology / 药学学报

A novel mucoadhesive microcapsule with drug-resin complex core loaded with berberine hydrochloride (BH) was developed and optimized. Drug-ion exchange resin (IER) complex was prepared by static method which stirring IER in drug solution at certain conditions. The influences of different IERs, different temperature, pH values and concentrations of drug solution on the drug loading were investigated. IER complex was coated by emulsion-solvent evaporation method. The coating fluid formulation was optimized using central composite design-response surface methodology, where the ratio between Carbopol 934 and IER (X1), the ratio between Eudragit and IER (X2) and the ratio between Eudragit RL and RS (X3) were taken as independent variables. Time of cumulative release 85% (Y1) and percentage of gastric retention (Y2) were taken as response variables. Drug loading achieved a high level and more drug available in the condition of IER (IRP 88), 37 degrees C, pH 5 and 1.0 mg x mL(-1) drug solution. When X1 = 0.75, X2 = 0.9, X3 = 0.6, the time of cumulative release reached 85% at 300 min, the highest percentage of gastric retention in the range of this experiment were procured.

Study on in vitro release empirical method and the release mechanism of budesonide colonic localization tablet / 药学学报

The three-step dissolution experiment was established to investigate the in vitro release of budesonide colon-specific tablet and to elucidate the drug release mechanism by fitting to different mathematical models. The physiological parameters of stomach, small intestine and colon such as pH value, intestinal flora, specific organic enzyme, vermiculation and conveying time were mimicked to plot the in vitro dissolution, separately. Sample were taken at predetermined time intervals in 24 h and the accumulated drug releases were determined by using HPLC method. Drug release curves of the localization tablets were fitted to various mathematical models. It shows that no drug release was found in 2 h. About 5% release was determined after 6 h while 77.5% accumulated release was reached within 24 h. Drug release from the in house formulation fitted well into first-order model. The three-step dissolution method could be used to evaluate the colon-specific characteristics of budesonide colonic localization tablet. The drug release behavior of the localization tablet conforms to the drug release mechanisms of controlled porosity osmotic pump where osmotic pressure is the main driving force for controlled delivery of drugs.

Study on ingredients of essential oils of Curcuma wenyujin extracted by supercritical-CO2 fluid extraction and steam distillation / 中国中药杂志

<p><b>OBJECTIVE</b>To compare the ingredients of essential oils of Curcuma wenyujin extracted by supercritical-CO2 fluid extraction and by steam distillation.</p><p><b>METHOD</b>GC-MS was applied in this experiment.</p><p><b>RESULT</b>The ingredients and physical and chemical properties of essential oils of C. wenyujin extracted by supercritical-CO2 fluid extraction and by steam distillation are similar.</p><p><b>CONCLUSION</b>Supercritical-CO2 fluid extraction is better than steam distillation in extraction time, power consumption, recovery and purity.</p>

The pharmacokinetics and bioequivalence of acipimox sustained-release tablets after a single and multiple oral administration in healthy dogs / 药学学报

<p><b>AIM</b>To study the pharmacokinetics and bioequivalence of acipimox sustained-release tablets (SRT) after a single and multiple oral dose in healthy dogs.</p><p><b>METHODS</b>The plasma concentrations of of SRT and reference capsules with a single and multiple oral doses.</p><p><b>RESULTS</b>The drug concentration-time profiles fitted to a noncompartment model. After a single dose administration of sustained-release tablets and capsules, the pharmacokinetic parameters were as follows: AUC were (158 +/- 30) and (147 +/- 37) microg x h x mL(-1); Tmax were (4.3 +/- 0.8) and (2.6 +/- 1.3) h; Cmax were (29 +/- 6) and (42 +/- 10) microg x mL(-1); T(1/2) were (2.3 +/- 0.7) and (1.60 +/- 0.10) h; MRT were (6.0 +/- 0.8) and (3.9 +/- 0.7) h, respectively. The relative bioavailability of the sustained-release tablet was (108 +/- 16) %. After a multiple oral administration of sustained-release tablets and capsules, the pharmacokinetic parameters were as follows: AUC were (209 +/- 23) and (195 +/- 26) microg x h x mL(-1); Tmax were (6.3 +/- 0.8) and (3.4 +/- 1.5) h; Cmax were (27 +/- 4) and (36 +/- 5) microg x mL(-1); Cmmin were (2.2 +/- 1.0) and (0.20 +/- 0.20) microg x mL(-1); Cav were (8.7 +/- 1.0) and (8.1 +/- 1.1) micro x mL(-1); FI were (293 +/- 73) % and (448 +/- 91) % , respectively. The relative bioavailability of the sustained-release tablet was (114 +/- 19) %.</p><p><b>CONCLUSION</b>The results of two one-side test from single dose administration shown that two preparations were bioequivalent. The Cmax of sustained-release tablet was lower than that of capsules, while the Tmax and MRT of sustained-release tablet were higher than that of capsule, which indicating a good retarding effect. The results from multiple dose administration also shown that two preparations were bioequivalent and the DF of sustained-release tablet was significant lower than that of capsule.</p>