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Aging‐related alterations in hepatic enzyme activity, particularly of the CYP3A, significantly impact drug efficacy and safety in older adults, making it essential to understand how aging affects CYP function for optimal drug therapy. The exogenous probe substrate method, a minimally invasive approach to assess liver metabolic enzyme activity in vivo, is effective in studying these changes. Amlodipine being extensively metabolized (> 90%) in the liver, primarily via cytochrome P450 enzyme CYP3A was selected as a probe to investigate and quantify the factors affecting the aging‐related changes of CYP3A in the Chinese older population. Amlodipine concentration data were collected from an ongoing noninterventional clinical study conducted at Peking University Third Hospital. A physiologically‐based pharmacokinetic modeling approach, grounded in population pharmacokinetic (PPK) analysis, was employed to physiologically quantify the aging‐related changes in CYP3A function. A total of 132 amlodipine concentrations from 69 patients were obtained from the clinical study. PPK analysis shows that frailty phenotype but not age is a significant influence and frail patients have 37% greater plasma amlodipine exposure than nonfrail patients. This difference in CYP3A function may be attributed to a 63.2% lower CYP3A relative abundance in the frail patients, compared with that in the nonfrail patients. In the context of dose selection for older adults, focusing on frailty rather than chronological age should be recognized as a more relevant approach, because frailty might more accurately reflect the individual's biological age. Our study suggested a need to shift the research focus from chronological age to biological age. [ABSTRACT FROM AUTHOR]

In this study, a multi-component integrated dissolution evaluation system of Yuanhu Zhitong tablets (YZTs) was established based on in vitro and in vivo correlation (IVIVC). The dissolution tests of five quality markers (Q-markers), including tetrahydropalmatine, α-allocryptopine, protopine, corydaline, and byakangelicin, in YZTs were conducted under different dissolution conditions, and pharmacokinetic studies were performed in beagle dogs to construct a correlation model using numerical deconvolution. The data of the five ingredients were integrated in vitro and in vivo according to the biopharmaceutical classification system (BCS) to establish an IVIVC integrating multiple Q-markers. The dissolution media with the best correlation of components were obtained and validated. The results showed that all five components were classified as BCS I compounds, and α-allocryptopine, byakangelicin, tetrahydropalmatine, and corydaline showed good correlation in the paddle method, 75 rpm, with dissolution media of artificial gastric fluid, acetate buffer, acetate buffer and 0.1 M HCl, respectively. Protopine showed good correlation in the paddle method, 100 rpm, with dissolution media of 0.1 M HCl. The integrated BCS I Q-markers showed the best correlation in the medium of acetate buffer. The multi-component integrated dissolution evaluation system established in this experiment accurately predicted the pharmacokinetic data of YZTs by verifying the media, which can be used for the quality control of YZTs. The present study provides an effective and promising strategy for the dissolution evaluation for traditional Chinese medicine preparations. [ABSTRACT FROM AUTHOR]

Background: Caspofungin is an echinocandin antifungal agent commonly used as the first-line therapy for invasive candidiasis, salvage therapy for invasive aspergillosis, and empirical therapy for presumed fungal infections. Pharmacokinetic (PK) variabilities and suboptimal exposure have been reported for caspofungin, increasing the risk of insufficient efficacy. Objective: This work aimed to develop a caspofungin population pharmacokinetic (popPK) library and demonstrate its utility by assessing the probability of target attainment across diverse settings. Methods: We established a caspofungin popPK model library following a rigorous literature review, re-implementing selected models in R with rxode2. Quality control procedures included a comparison of different studies and assessing covariate impacts. Model libraries were primarily used to perform Monte Carlo simulations to estimate target attainment and guide personalized dosing in Candida infections. Results: A total of 13 models, one- or two-compartment models, were included. The most significant covariates were body size (weight and body surface area), liver function, and albumin level. The results show that children and adults showed considerable differences in pharmacokinetics. For C. albicans and C. parapsilosis, none of the populations achieved a PTA of ≥90% at their respective susceptible MIC values. In contrast, for C. glabrata, 70% of the adult studies reached a PTA of ≥90%, while all pediatric studies achieved the same PTA level. Conclusion: At the recommended dosage, adult patients showed notably lower exposure to caspofungin compared to pediatric patients. Considering body size, liver function, and serum albumin is crucial when determining caspofungin dosage regimens. Furthermore, further research is required to comprehensively understand the pharmacokinetics of caspofungin in pediatric patients. [ABSTRACT FROM AUTHOR]