Model-based precision dosing and remedial dosing recommendations for delayed or missed doses of isoniazid in Chinese patients with tuberculosis.

AIMS: Isoniazid (INH) has been used as a first-line drug to treat tuberculosis (TB) for more than 50 years. However, large interindividual variability was found in its pharmacokinetics, and effects of nonadherence to INH treatment and corresponding remedy regime remain unclear. This study aimed to develop a population pharmacokinetic (PPK) model of INH in Chinese patients with TB to provide model-informed precision dosing and explore appropriate remedial dosing regimens for nonadherent patients. METHODS: In total, 1012 INH observations from 736 TB patients were included. A nonlinear mixed-effects modelling was used to analyse the PPK of INH. Using Monte Carlo simulations to determine optimal dosage regimens and design remedial dosing regimens. RESULTS: A 2-compartmental model, including first-order absorption and elimination with allometric scaling, was found to best describe the PK characteristics of INH. A mixture model was used to characterize dual rates of INH elimination. Estimates of apparent clearance in fast and slow eliminators were 28.0 and 11.2 L/h, respectively. The proportion of fast eliminators in the population was estimated to be 40.5%. Monte Carlo simulations determined optimal dosage regimens for slow and fast eliminators with different body weight. For remedial dosing regimens, the missed dose should be taken as soon as possible when the delay does not exceed 12 h, and an additional dose is not needed. delay for an INH dose exceeds 12 h, the patient only needs to take the next single dose normally. CONCLUSION: PPK modelling and simulation provide valid evidence on the precision dosing and remedial dosing regimen of INH.

[Effects of Pesticides Use on Pesticides Residues and Its Environmental Risk Assessment in Xingkai Lake（China）].

Xingkai Lake, located in Heilongjiang Province, is an important fishery and agricultural base and is seriously polluted by agricultural non-point sources. To clarify the residual status of many pesticides in the surface water of Xingkai Lake, 27 types of pesticides, herbicides, and their degradation products were analyzed in rice paddy, drainage, and surface water around Xingkai Lake (China) during the rice heading and maturity periods. The results showed that all 27 types of pesticides, herbicides, and their degradation products were detected during the rice heading period, and the total concentration ranged from 247.97 to 6 094.49 ng·L-1. Additionally, 25 species were detected during the rice maturity period, and the total concentration ranged from 485.36 to 796.23 ng·L-1. In comparison, more pesticides, herbicides, and derived degradation products were detected during the heading period, and their total concentration was higher as well. During the rice heading period, atrazine, simetryn, and paclobutrazol were the main detected pesticides, atrazine and isoprothiolane were the main pesticides detected during the maturity period. The distribution characteristics of pesticides and herbicides in the surface water around Xingkai Lake (China) was similar to that in drainage, so they were probably imported from the drainage and rice paddy. The average risk quotient (RQ) values of atrazine, simetryn, prometryn, butachlor, isoprothiolane, and oxadiazon were higher than 0.1 in drainage and Xingkai Lake (China), which showed a potential risk to aquatic organisms.