Pharmacokinetics of Nifedipine-Sustained Release Tablets in Healthy Subjects After a Single Oral Administration: Bioequivalence Analysis and Food Effects.

We compared newly developed delayed-release oral tablets (test) of 30-mg nifedipine (NFP) with its marketed counterpart (30 mg; reference) in healthy adult Chinese volunteers to assess the former's bioequivalence. This was a randomized, open-label, four-period, crossover trial study including fasting and fed trials. The participants were randomly administered test or reference formulations (1:1 ratio) throughout each period, with a 7-day washout period. In the next session, they were administered the alternate products. Liquid chromatography-tandem mass spectrometry and WinNonlin software were used to evaluate the bioequivalence of the maximum plasma concentration (Cmax ) of NFP and the area under the concentration-time curve (AUC). In total, 46 and 48 people participated in the fasting and postprandial trials. In both groups, the 90% confidence intervals of geometric mean ratios of Cmax , AUC from time zero to time t, and AUC from time zero to infinity were in the equivalence range (80%-125%). When NFP was administered concomitantly with a high-fat meal, time to maximum concentration was approximately twofold earlier, absorption was approximately 4.8% less, and Cmax exhibited a slight change relative to those under fasting conditions. Moreover, no serious adverse events were recorded in the participants. The present findings confirm the bioequivalence of test and reference formulations of NFP tablets under fasting and postprandial conditions.

Pharmacokinetics of Esomeprazole Magnesium After Single Oral Doses in Healthy Subjects: Bioequivalence Study and Food Effects.

This study was designed to evaluate the bioequivalence of the newly developed delayed-release oral suspension (test) 40 mg esomeprazole magnesium compared to its marketed counterpart (40 mg; reference) in healthy adult Chinese subjects. We conducted randomized, open-label, two-period, single-dose, two-way crossover trials over a 7-day washout period, comprising a fasting trial and a fed trial. The subjects were administered the test or reference products in a 1:1 ratio at random throughout each period. Then, in the next session, they received the alternate products. Liquid chromatography-tandem mass spectrometry and WinNonlin software were used to assess the bioequivalence of esomeprazole peak plasma concentration (Cmax ) and area under the concentration-time curve (AUC). Overall, 33 subjects participated in the fasting trial and 42 subjects participated in the fed trial. Under both situations, the 90% confidence interval for the ratio of geometric means of Cmax , AUC0-t , and AUC0-∞ were within equivalence ranges (80%-125%). In these trials, no severe adverse events or protocol violations were observed. Moreover, when esomeprazole was administered while fed, the tmax was delayed, and both Cmax and AUC were reduced. The results of this research suggest that the test and reference formulations were bioequivalent under fasting and fed states.

[Survey on the epidemic characteristics of suicidal tendency among middle-school students in cities].

OBJECTIVE: To identify the epidemical characteristics of suicidal tendency among middle-school students in cities of China and to explore the main factors leading to suicidal tendency in adolescents. METHODS: Multi-stage cluster sampling method was used to select 9015 students in grades 1, 2, 3 and 4 respectively from 25 general middle schools in Beijing, Hangzhou, Wuhan and Urumqi of China in June 2006 and field investigation was carried out through "China Global School-based Student Health Survey (GSHS) Questionnaire". RESULTS: Among the students in the four cities, the incidence rates of suicidal ideation were from 14.4% to 20.8% with an average of 17.4%. The incidence rates of suicidal plan were from 6.8% to 9.7% with an average of 8.2% and were different among cities. 15.0% of the boys had suicidal ideation and 6.7% of them made a suicidal plan comparing to 19.7% of girls having had suicidal ideation and 9.5% of them made a suicidal plan. The two kinds of suicidal tendency in girls were all higher than those in boys. City, age, gender, grade, days and type of being bullied, depression, close friends and having received health education on coping with stresses were factors influencing suicidal tendency of students. Days of being bullied and suicidal tendency showed a dose-response relation. CONCLUSION: Suicidal tendency seemed common in middle-school students. Training on 'coping the issue' should be strengthened and harmonious environment should be improved in middle-schools.