Browsing by Author "Manupat Lohitnavy"

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    Assessing clinical evidence of drug interactions between citrus juices and cyclosporine
    (2013-08-01) Pakawadee Sermsappasuk; Nathorn Chaiyakunapruk; Manupat Lohitnavy; Chagriya Kitiyakara; Naresuan University; University of Queensland; University of Wisconsin Madison; Mahidol University
    Background: Previous studies have demonstrated that grapefruit juice increased the bioavailability of cyclosporine;however, the results from the literature are inconsistent. Other citrus fruits such as pomelo or orange juice had variable effects on the bioavailability of cyclosporine.Objective: To assess the effect of grapefruit juice and other types of citrus juice on oral bioavailability of cyclosporine in humans using meta-Analysis.Methods: We conducted a meta-Analysis of placebo-controlled studies evaluating the effects of citrus juices on bioavailability of cyclosporine. The studies were identified in PubMed, Cochrane CENTRAL, CINAHL, ISI Web of Knowledge, Psych Info International, Pharmaceutical Abstract (IPA), and reference lists of relevant papers. The weighted-mean difference (WMD) was calculated for net changes in the area under the curve (AUC) of cyclosporine. All studies conducted as placebo-controlled crossover studies in humans to compare the effect of citrus juices and control (drinking water) on AUC of cyclosporine and/or Cmin,ss were reviewed. All studies included were evaluated and extracted independently, and discrepancies were resolved through discussion.Results: Eighteen studies were identified. A subgroup analysis suggested that grapefruit juice significantly increased AUC of cyclosporine (WMD = 1762.5 ng·h/ml, 95%CI = 1178.9-2346.0 ng·h/ml, p > 0.001). While a meta-Analysis of all other types of citrus juices (tangerine juice, Seville orange juice, sweet orange juice, and citrus soda) except pomelo juice revealed no effect on the AUC of cyclosporine (WMD = -181.0 ng·h/ml,95%CI = -582.8-220.9 ng·h/ml, p > 0.5), a study of pomelo juice indicated a significant increase in the AUC of cyclosporine.Conclusions: Grapefruit juice intake increases oral bioavailability of cyclosporine in both healthy volunteers and renal transplant patients, whereas all other types of citrus juices may not have an influence on the oral bioavailability of cyclosporine. Current evidence suggests that pomelo juice may be able to increase cyclosporine oral bioavailability.
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    Development of a Physiologically Based Pharmacokinetic Model of Mitragynine, Psychoactive Alkaloid in Kratom (Mitragyna Speciosa Korth.), In Rats and Humans
    (2021-01-01) Kimheang Ya; Janthima Methaneethorn; Quoc Ba Tran; Satariya Trakulsrichai; Winai Wananukul; Manupat Lohitnavy; Duy Tan University; Naresuan University; Faculty of Medicine Ramathibodi Hospital, Mahidol University
    Mitragynine is a major psychoactive alkaloid in leaves of kratom (Mitragyna speciosa Korth.). To understand its disposition in organs, this study aimed to develop a physiologically based pharmacokinetic (PBPK) model that predicts mitragynine concentrations in plasma and organ of interests in rats and humans. The PBPK model consisted of six organ compartments (i.e. lung, brain, liver, fat, slowly perfused tissues, and rapidly perfused tissue). From systematic searching, three pharmacokinetic studies of mitragynine (two studies in rats and 1 study in humans) were retrieved from the literature. Berkeley Madonna Software (version 8.3.18) was used for model development and model simulation. The developed PBPK model consisted of biologically relevant features following involvement of (i) breast cancer-resistant protein (BCRP) in brain, (ii) a hepatic cytochrome P450 3A4 (CYP3A4)-mediated metabolism in the liver, and (iii) a diffusion-limited transport in fat. The simulations adequately describe simulated and observed data in the two species with different dosing regimens. PBPK models of mitragynine in rats and humans were successfully developed. The models may be used to guide optimal mitragynine dosing regimens.