The pharmacokinetic differences between 10- and 15-µg daily vitamin D doses.

AIMS: The reference nutrient intake for vitamin D in people aged ≥4 years is 10 µg/day (400 IU/day) in the UK, but the recommended daily allowance is 15 µg/day (600 IU/day) for people aged 1-70 years in the USA. Here, we aim to compare the 25-hydroxyvitamin D (25(OH)D) serum concentration profiles between the 2 doses. METHODS: With world-wide trial data of adults aged ≥18 years, 45-93 kg, we constructed a minimal physiologically based pharmacokinetics model of serum concentrations of vitamin D and 25(OH)D using nonlinear mixed effects modelling. We used this model to forecast the mean, 2.5th and 97.5th percentiles for serum 25(OH)D concentrations in British adults aged ≥16 years. RESULTS: Our final model used bodyweight to adjust volume of each compartment and maximum clearance of 25(OH)D. No other covariate was identified. The model accurately predicted independent data from trials of a broad range of dosing regimens. We simulated British adults and showed that circulating 25(OH)D concentrations in 95% of people taking 10 µg/day for a year is predicted to reach 50 nmol/L in 32 weeks, while 97.5% of those on 15 µg/day were predicted to attain this threshold within 28 weeks. CONCLUSION: Both doses are efficacious in >95% of the British population. The daily dose of 15 µg can help 97.5% of the British adults achieve 50 nmol/L serum 25(OH)D and reach the 25 nmol/L threshold in 4 weeks.

The roles of CYP2C19 and CYP3A4 in the in vitro metabolism of ß-eudesmol in human liver: Reaction phenotyping and enzyme kinetics.

ß-eudesmol is a major bioactive component of Atractylodes lancea (AL). AL has been developed as the capsule formulation of standardized AL extract for treating cholangiocarcinoma (CCA). However, the complex constituents of herbal products increase the risk of adverse drug interactions. ß-eudesmol has demonstrated inhibitory effects on rCYP2C19 and rCYP3A4 in the previous research. This study aimed to identify the cytochrome P450 (CYP) isoforms responsible for the metabolism of ß-eudesmol and determine the enzyme kinetic parameters and the metabolic stability of ß-eudesmol metabolism in the microsomal system. Reaction phenotyping using human recombinant CYPs (rCYPs) and selective chemical inhibitors of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 was performed, and enzyme kinetics and metabolic stability were investigated using human liver microsome (HLM). The results suggest that CYP2C19 and CYP3A4 play significant roles in ß-eudesmol metabolism. The disappearance half-life (t1/2 ) and intrinsic clearance (CLint ) of ß-eudesmol were 17.09 min and 0.20 mL/min·mg protein, respectively. Enzyme kinetic analysis revealed the Michaelis-Menten constant (Km ) and maximum velocity (Vmax ) of 16.76 µM and 3.35 nmol/min·mg protein, respectively. As a component of AL, ß-eudesmol, as a substrate and inhibitor of CYP2C19 and CYP3A4, has a high potential for drug-drug interactions when AL is co-administered with other herbs or conventional medicines.

Bioassay for total serum bioactivity of Atractylodes lancea.

The study aimed to establish a bioassay for total bioactivity of Atractylodes lancea (AL) in human serum samples. Inhibition of bacterial growth (Staphylococcus aureus ATCC 25923) was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The calibration curve (0, 0.39, 0.78, 1.56, 3.13, 2.56, and 50 ng/µl) was linear with correlation coefficients >0.990. The limit of quantification (LOQ) was 1.66 mg/ml using 20-ml serum sample. The developed bioassay method meets the standard of the bioanalytical method for determination of serum bioactivity of AL.

Atractylodes lancea for cholangiocarcinoma: Modulatory effects on CYP1A2 and CYP3A1 and pharmacokinetics in rats and biodistribution in mice.

Atractylodes lancea (Thunb.) DC. (A. lancea: AL) is a promising candidate for the treatment of cholangiocarcinoma (bile duct cancer). The study investigated (i) the propensity of capsule formulation of the standardized extract of AL (formulated AL) to modulate mRNA and protein expression and activities of CYP1A2 and CYP3A1 in rats after long- and short-term exposure, (ii) the pharmacokinetics of atractylodin (ATD: active constituent) after long-term administration of formulated AL, and (iii) the biodistribution of atractylodin-loaded polylactic-co-glycolic acid (ATD-PLGA-NPs) in mice. To investigate CYP1A2 and CYP3A1 modulatory activities following long-term exposure, rats of both genders received oral doses of the formulated AL at 1,000 (low dose), 3,000 (medium dose), and 5,000 (high dose) mg/kg body weight daily for 12 months. For short-term effects, male rats were orally administered the formulated AL at the dose of 5,000 mg/kg body weight daily for 1, 7, 14 and 21 days. The pharmacokinetic study was conducted in male rats after administration of the formulated AL at the dose of 5,000 mg/kg body weight daily for 9 months. The biodistribution study was conducted in a male mouse receiving ATD-PLGA-NPs at the equivalent dose to ATD of 100 mg/kg body weight. The high dose of formulated AL produced an inducing effect on CYP1A2 but an inhibitory effect on CYP3A1 activities in male rats. The low dose, however, did not inhibit or induce the activities of both enzymes in male and female rats. ATD reached maximum plasma concentration (Cmax) of 359.73 ng/mL at 3 h (tmax). Mean residence time (MRT) and terminal phase elimination half-life (t1/2z) were 3.03 and 0.56 h, respectively. The extent of biodistribution of ATD in mouse livers receiving ATD-PLGA-NPs was 5-fold of that receiving free ATD. Clinical use of low-dose AL should be considered to avoid potential herb-drug interactions after long-term use. ATD-PLGA-NPs is a potential drug delivery system for cholangiocarcinoma treatment.

Phase I clinical trial to evaluate the safety and pharmacokinetics of capsule formulation of the standardized extract of Atractylodes lancea.

BACKGROUND AND AIM: Atractylodes lancea (AL) has been demonstrated in a series of studies to be a potential candidate for the treatment of cholangiocarcinoma. The aim of the current study was to evaluate the safety and pharmacokinetics of the capsule formulation of the standardized AL extract in healthy Thai participants. EXPERIMENTAL PROCEDURE: Forty-eight healthy Thai participants who fulfilled the inclusion and had none of the exclusion criteria were allocated to two study groups. The group 1 participants were randomized to receive a single oral dose of 1,000 mg of AL or placebo (20:4 participants). The group 2 participants were randomized to receive daily oral doses of 1,000 mg AL or placebo daily for 21 days (20:4 participants). Safety and tolerability of the two AL regimens were monitored. Blood samples were collected for measurement of atractylodin concentrations by HPLC and pharmacokinetic analysis was performed using model-dependent and model-independent analysis. RESULTS AND CONCLUSION: The AL extract was well tolerated in both groups. Atractylodin was rapidly absorbed but with low systemic exposure and residence time. There was no difference in the pharmacokinetic parameters of atractylodin following a single or multiple dosing, suggesting the absence of accumulation and dose-dependency in human plasma after continuous dosing for 21 days. The information on human pharmacokinetics of AL, when given as capsule formulation of the standardized extract, would assist in further dose optimization in cholangiocarcinoma patients with the defined pharmacokinetic-pharmacodynamic relationship.

Metabolite Profiling in Anticancer Drug Development: A Systematic Review.

Drug metabolism is one of the most important pharmacokinetic processes and plays an important role during the stage of drug development. The metabolite profile investigation is important as the metabolites generated could be beneficial for therapy or leading to serious toxicity. This systematic review aims to summarize the research articles relating to the metabolite profile investigation of conventional drugs and herb-derived compounds for cancer chemotherapy, to examine factors influencing metabolite profiling of these drugs/compounds, and to determine the relationship between therapeutic efficacy and toxicity of their metabolites. The literature search was performed through PubMed and ScienceDirect databases up to January 2019. Out of 830 published articles, 78 articles were included in the analysis based on pre-defined inclusion and exclusion criteria. Both phase I and II enzymes metabolize the anticancer agents/herb-derived compounds . The major phase I reactions include oxidation/hydroxylation and hydrolysis, while the major phase II reactions are glucuronidation, methylation, and sulfation. Four main factors were found to influence metabolite formation, including species, gender, and route and dose of drug administration. Some metabolites were identified as active or toxic metabolites. This information is critical for cancer chemotherapy and anticancer drug development.

Application of active targeting nanoparticle delivery system for chemotherapeutic drugs and traditional/herbal medicines in cancer therapy: a systematic review.

Patients treated with conventional cancer chemotherapy suffer from side effects of the drugs due to non-selective action of chemotherapeutic drugs to normal cells. Active targeting nanoparticles that are conjugated to targeting ligands on the surface of nanoparticles play an important role in improving drug selectivity to the cancer cell. Several chemotherapeutic drugs and traditional/herbal medicines reported for anticancer activities have been investigated for their selective delivery to cancer cells by active targeting nanoparticles. This systematic review summarizes reports on this application. Literature search was conducted through PubMed database search up to March 2017 using the terms nanoparticle, chemotherapy, traditional medicine, herbal medicine, natural medicine, natural compound, cancer treatment, and active targeting. Out of 695 published articles, 61 articles were included in the analysis based on the predefined inclusion and exclusion criteria. The targeting ligands included proteins/peptides, hyaluronic acid, folic acid, antibodies/antibody fragments, aptamer, and carbohydrates/polysaccharides. In vitro and in vivo studies suggest that active targeting nanoparticles increase selectivity in cellular uptake and/or cytotoxicity over the conventional chemotherapeutic drugs and non-targeted nanoparticle platform, particularly enhancement of drug efficacy and safety. However, clinical studies are required to confirm these findings.