Experimental Research on Measuring the Concentration of CO2 in Gas-Liquid Solution Based on PZT Piezoelectric-Photoacoustic Spectroscopy.

The feasibility of a scheme in which the concentration of CO2 in gas-liquid solution is directly measured based on PZT piezoelectric-photoacoustic spectroscopy was evaluated. The existing device used for the measurement of gas concentration in gas-liquid solution has several limitations, including prolonged duration, loss of gas, and high cost due to the degassing component. In this study, we developed a measuring device in order to solve the problems mentioned above. Using this device, how the intensity of the photoacoustic signal changes with the concentration of CO2 was demonstrated through experiment. The impact that variation of the laser modulation frequency has on the photoacoustic signal was also studied. Furthermore, the experimental data generated from measuring the concentration of CO2 in gas-liquid solution was verified for a wide range of concentrations. It was found that, not only can the error rate of the device be less than 7%, but the time of measurement can be within 60 s. To sum up, the scheme is highly feasible according to the experimental results, which makes measurement of the concentration of a gas in gas-liquid solution in the future more straightforward.

Pharmacokinetic Study of Frovatriptan Succinate Tablet After Single and Multiple Oral Doses in Chinese Healthy Subjects.

PURPOSE: The present report describes findings from a Phase I clinical study that evaluated the single- and multiple-dose pharmacokinetics of frovatriptan succinate tablet in Chinese healthy subjects. METHODS: A total of 24 healthy subjects were enrolled. In single-dose study, 2.5, 5, and 10 mg oral doses of frovatriptan succinate tablet were administrated. A 2.5 mg frovatriptan succinate tablet was administrated 12 times in 7 days in the multiple-dose study. Blood samples were collected at scheduled time points. RESULTS: The results in single-dose study indicated that the blood levels were proportional to the administered dose, with the mean Cmax and AUClast ranging from approximately 6.27 ng/mL-17.35 ng/mL and 92.52 h⋅ng/mL - 287.40 h⋅ng/mL over the dose range. In the multiple-dose study, moderate drug accumulation was noted, which was attributable to forvatriptan's long t1/2 of about 26.47 to 30.63 h. Gender differences were noticed in both single- and multiple-dose study; exposure PK parameters were consistently higher in female than in male. CONCLUSION: These pharmacokinetic evaluations in healthy Chinese subjects found that frovatriptan succinate tablet has an acceptable pharmacokinetic profile in Chinese subjects.

Pharmacokinetics and Bioequivalence of 2 Olanzapine Orally Disintegrating Tablet Products in Healthy Chinese Subjects Under Fed and Fasting Conditions.

To assess the bioequivalence of two 5-mg olanzapine orally disintegrating tablet (ODT) products, 2 randomized, open-label, single-dose, 2-way crossover studies were carried out under fasting or fed conditions. Blood samples were collected at scheduled times according to the study protocol. Statistical analysis of area under the concentration-time curve from time 0 to 168 hours (AUC0-t ), area under the curve from time zero to infinity (AUC0-∞ ), and peak plasma concentration (Cmax ) was conducted. Two formulations were considered bioequivalent if the 90% confidence intervals (CIs) of the geometric mean ratios for AUC0-t, AUC0-∞ , and Cmax were within the range of 0.80-1.25. Adverse events were recorded and evaluated throughout the studies. A total of 48 subjects with 24 in each study completed the 2 studies. In fasted subjects, the 90%CIs for the test product versus the reference product were 97.28%-105.13% for AUC0-t , 97.57%-105.54% for AUC0-∞ , and 90.94%-103.97% for Cmax . In fed subjects, the 90%CIs for AUC0-t , AUC0-∞ and Cmax were 99.73%-122.63%, 99.56%-121.75%, and 99.46%-120.46%, respectively. No serious adverse events were reported in the studies. The reference and the test product of 5-mg olanzapine ODT show comparable pharmacokinetic profiles under both fed and fasted conditions and were considered bioequivalent.