Developing a QSPR Model of Organic Carbon Normalized Sorption Coefficients of Perfluorinated and Polyfluoroalkyl Substances.

Perfluorinated and polyfluoroalkyl substances (PFASs) are known for their long-distance migration, bioaccumulation, and toxicity. The transport of PFASs in the environment has been a source of increasing concerned. The organic carbon normalized sorption coefficient (Koc) is an important parameter from which to understand the distribution behavior of organic matter between solid and liquid phases. Currently, the theoretical prediction research on log Koc of PFASs is extremely limited. The existing models have limitations such as restricted application fields and unsatisfactory prediction results for some substances. In this study, a quantitative structure-property relationship (QSPR) model was established to predict the log Koc of PFASs, and the potential mechanism affecting the distribution of PFASs between two phases from the perspective of molecular structure was analyzed. The developed model had sufficient goodness of fit and robustness, satisfying the model application requirements. The molecular weight (MW) related to the hydrophobicity of the compound; lowest unoccupied molecular orbital energy (ELUMO) and maximum average local ionization energy on the molecular surface (ALIEmax), both related to electrostatic properties; and the dipole moment (µ), related to the polarity of the compound; are the key structural variables that affect the distribution behavior of PFASs. This study carried out a standardized modeling process, and the model dataset covered a comprehensive variety of PFASs. The model can be used to predict the log Koc of conventional and emerging PFASs effectively, filling the data gap of the log Koc of uncommon PFASs. The explanation of the mechanism of the model has proven to be of great value for understanding the distribution behavior and migration trends of PFASs between sediment/soil and water, and for estimating the potential environmental risks generated by PFASs.

Pharmacokinetics and Preliminary Pharmacodynamics of Single- and Multiple-dose Lyophilized Recombinant Glucagon-like Peptide-1 Receptor Agonist (rE-4) in Chinese Patients with Type 2 Diabetes Mellitus.

BACKGROUND AND OBJECTIVES: Recombinant glucagon-like peptide-1 receptor agonist (rE-4) is a glucagon-like peptide-1 receptor agonist, which has the same amino acid sequence to exenatide, except for the C-terminal deamidated. This study assessed the pharmacokinetics and preliminary pharmacodynamics of rE-4, following single and multiple subcutaneous injections in Chinese patients with type 2 diabetes mellitus (T2DM). DESIGN AND METHODS: In the randomized, open-label study, Chinese patients with T2DM (n = 36) were randomly assigned to three groups of rE-4 (n = 12), rE-4 with metformin (n = 12) and exenatide (n = 12, as the control group) for 12 weeks. rE-4 and exenatide were administered by subcutaneous injection in the abdomen, and metformin was given by oral administration. Patients received rE-4 or exenatide 5 µg twice a day for the first 4 weeks and adjusted the dose of rE-4 or exenatide to 10 µg twice a day at day 29 for the following 8 weeks, if their glycated albumin (GA) values were still greater than 17%. We evaluated pharmacokinetic parameters of rE-4 and exenatide, fasting plasma glucose (FPG), 2-h postprandial blood glucose (PG2 h), glycosylated hemoglobin (HbA1c) and body weight at designated time points. RESULTS: Thirty-six patients were enrolled, and 29 subjects finished the study. rE-4 was absorbed quickly with a median peak-reaching time (t max) of 0.8-1.5 h and eliminated rapidly with a median terminal half-life (t 1/2z) of 1.6-1.9 h. The exposure of rE-4 increased in an approximately dose-proportional method without accumulation. rE-4 10 µg twice a day could reduce FPG (~2.29 mmol/L), PG2 h (~6.00 mmol/L), HbA1c (~1.19%) and body weight (~0.48 kg) from baseline to 12 weeks, with no statistical significance compared with exenatide (FPG: ~1.88 mmol/L; PG2 h: ~6.66 mmol/L; HbA1c: ~1.13%; body weight: ~0.47 kg) and rE-4 with metformin (FPG: ~2.33 mmol/L; PG2 h: ~6.51 mmol/L; HbA1c: ~0.84%; body weight: ~1.16 kg) (p > 0.05). CONCLUSIONS: rE-4 twice a day has a pharmacokinetic profile similar to exenatide and rE-4 with metformin after single and multiple doses in Chinese patients with T2DM. Also, rE-4 could improve glycemic control effectively. CLINICALTRIALS. GOV IDENTIFIER: NCT01342042.