Bioequivalence study of two formulations of terazosin hydrochloride capsule in healthy Chinese subjects under fasting and fed conditions.

OBJECTIVE: This study was conducted to assess the pharmacokinetic and safety profiles between a new oral formulation of terazosin hydrochloride capsule compared with the brand-name drug. MATERIALS AND METHODS: A randomized, open-label, single-dose, 2-period crossover study under fasting or fed conditions was conducted in healthy Chinese subjects. 24 individuals were selected, respectively. Each subject was randomized at the beginning to receive a 2-mg capsule of the test or the reference terazosin during the first period and then received the alternate formulation during the second period following a 1-week washout period. Blood samples were collected at pre-dose and up to 60 hours after administration. Plasma terazosin was quantified by a validated LC-MS/MS method. RESULTS: 48 healthy subjects were enrolled, and 47 completed the study. Cmax, AUC0-t, and AUC0-∞ were similar and the 90% CIs for the geometric mean ratios of these parameters between the two groups were all bounded within the predefined bioequivalence criterion of 80 - 125% under both fasting and fed conditions. Throughout the study period, a total of 30 treatment-emergent adverse events (TEAEs) were reported under fasting condition. 35 TEAEs were observed under fed conditions. No serious adverse event was observed. CONCLUSION: The test and reference formulations of terazosin were bioequivalent and well tolerated under both fasting and fed conditions.

Effect of Nutrient Addition on the Productivity and Species Richness of Grassland Along With an Elevational Gradient in Tajikistan.

Grasslands provide key resource for the millions of people who are dependent on livestock in Tajikistan. Productivity and species richness (SR) are important characteristics of grassland ecosystems and are greatly affected by nutrient inputs. The effect that climate change might have on these characteristics remains unclear. Here, an in situ nitrogen (N) and phosphorus (P) fertilization experiment was conducted at four sites along with an elevational gradient (650, 1,100, 1,250, and 2,000 m) in western Tajikistan over 2 years (2018 and 2019) to examine the influences of nutrient availability and climate change on aboveground biomass (AGB) and SR; precipitation and temperature were also considered to analyze the responses. It demonstrated that enrichment with N, P, and their combinations significantly increased AGB along with an elevational gradient (p < 0.05). AGB increased as the concentrations of nutrients added increased. The maximum AGB, which was 2-fold higher compared with control, was observed when 90 kg N ha-1year-1 and 30 kg P ha-1year-1 were added. In addition, nitrogen addition alone stimulated greater AGB than P addition, although no significant difference was observed between these two treatments. Enrichment with N, P, and their combination had no significant effect on SR; however, SR significantly changed at different elevation. Elevation had direct effect on precipitation and temperature, which, in turn, resulted in variation in AGB and SR. Moreover, both nutrient and elevation had significant effect on AGB and SR, but there was no interaction effect of them. AGB and SR interacted with significant negative correlation. In the high-elevation area, plants grew better in the warmer year (2018); this indicates that grasslands in high mountain areas in Tajikistan might have higher productivity as the climate warms, which will positively affect the economic development of the country.