Pharmacogenetic implementation for CYP2C19 and pharmacokinetics of voriconazole in children with malignancy or inborn errors of immunity

BACKGROUND

Voriconazole pharmacokinetics (PK) are known to be affected by genetic polymorphisms of drug-metabolizing enzymes such as CYP2C19; however, such information is limited for the pediatric population. The primary aim of this study is to establish a voriconazole PK model incorporating CYP2C19 phenotypes in Japanese children with malignancy or inborn errors of immunity.

METHODS

CYP2C19 genotypes were assessed by whole-genome genotyping and defined as follows: *17/*17: ultrarapid metabolizer (URM), *1/*17: rapid metabolizer (RM), *1/*1:normal metabolizer (NM), *1/*2, *1/*3, *2/*17:intermediate metabolizer (IM), and *2/*2, *2/*3, *3/*3: poor metabolizer (PM). Population PK analysis was performed. The voriconazole serum concentration profile was described by a two-compartment model with first-order absorption, mixed linear and nonlinear (Michaelis-Menten) elimination.

RESULTS

Voriconazole concentration data were available from 60 patients with a median age of 5.3 years. The phenotypes predicted from CYP2C19 genotypes were RM in 1 (2 %), NM in 21 (35 %) patients, IM in 27 (45 %) patients, and PM in 11 (18 %) patients. Underlying diseases included 38 (63%) patients with hematological malignancy and 18 (30 %) patients with inborn errors of immunity. Among the CYP2C19 phenotypes, PM was predicted to show complete inhibition (the degree of Vmax inhibition [Vmax, inh] = 100 %; Vmax = 0). The estimated parameters of Vmax,inh were +0.8 higher in patients with gamma-glutamyl transpeptidase (γ-GTP) Grade 2 or higher and +2.7 higher when C-reactive protein (CRP) levels were 2.0 mg/dL or higher.

CONCLUSION

CYP2C19 genetic polymorphisms, γ-GTP, and CRP affect Vmax,inh of voriconazole in children with malignancy or inborn errors of immunity.

Differences in in vivo absorption of flavone glycosides, flavone aglycones and terpene lactones under different dosage forms and physiological conditions

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. extract (GBE) oral preparations have been used for many years in the prevention and treatment of cardiovascular and cerebrovascular diseases, and the main active ingredients are flavonoids and terpene lactones. Among them, the oral absorption of the prototype components of flavonoid glycosides into the blood needs to be further clarified, and the differences in the oral absorption of different components in GBE by different dosage forms and physiological conditions are not clear yet.

AIM OF THE STUDY

To clarify the oral absorption of the prototype flavonoid glycosides in vivo, and to further explore the differences in the oral absorption of various active compounds under different oral dosage forms and dietary conditions.

MATERIALS AND METHODS

Firstly, the target compounds were selected based on the characteristic chromatogram of GBE and literature. Then, the content differences of three different oral GBE preparations were studied, and their pharmacokinetics (PK) were compared. Finally, the PK differences of the preparations with better oral absorption under different dietary conditions were studied.

RESULTS

Five flavonoid glycosides, three aglycones and four terpene lactones were selected as the research objects. The content determination results of GBE tablets, guttate pills and tinctures showed that the content of several components especially flavonoid glycosides in the tincture was higher than that of the other two preparations. After oral administration of these three preparations, the PK study showed different results from previous studies. The PK behavior of flavonoid glycosides was also determined at the same time as flavonoid glycosides and terpene lactones. and the bioavailability of flavonoid glycosides in the tincture was higher than that of the other two preparations. PK results of fasting and non-fasting showed that taking GBE tincture on an empty stomach increased the absorption of various compounds, especially flavonoid glycosides. However, due to the existence of food residues in the gastrointestinal tract, the oral bioavailability of flavonoid glycosides was significantly improved.

CONCLUSIONS

This study discussed the differences in the content and oral absorption of active compounds in different oral preparations of GBE, clarified the in vivo absorption of flavonoid glycosides prototype, as well as the influence of diet on the PK of active compounds, which has certain guiding significance for the clinical application of GBE oral preparations.

Quality by design approach for development and validation of a RP-HPLC method for simultaneous estimation of xipamide and valsartan in human plasma

A new rapid, simple, and sensitive RP-HPLC method was carried out through applying Quality by Design approach for determination of xipamide and valsartan in Human plasma. Fractional factorial design was used for screening of four independent factors: pH, flow rate, detection wavelength, and % of MeOH. Analysis of variance (ANOVA) confirmed that flow rate and % of MeOH were only significant. Chromatographic conditions optimization was carried out through using central composite design. Method analysis was performed using BDS Hypersil C8 column (250 × 4.6 mm, 5 μm) and an isocratic mobile phase of MeOH and 0.05 M KH2PO4 buffer pH 3 (64.5:35.5, v/v) at 1.2 mL/min flow rate with UV detection at 240 nm and 10 μL injection volume. According to FDA guidelines, the method was then validated for the determination of the two drugs clinically in human plasma in respect of future pharmacokinetic and bioequivalence simulation studies. The standard curve was linear in the concentration range of 5-100 µg/mL for both drugs, with a determination coefficient (R2) of 0.999. Also, the average recoveries lied within the range from 99.89 to 100.03%. The proposed method showed good predictability and robustness.

The Bioequivalence Between Valsartan Oral Solution and Suspension Formulations Developed for Pediatric Use

The bioequivalence of valsartan 160 mg oral solution compared to suspension was assessed in a single-dose, open-label, randomized, 2-period, 2-way crossover study in 82 healthy adults. The participants were randomly assigned (1:1) to receive a single dose of the solution or suspension formulation in each of the two treatment periods. Serial blood samples for pharmacokinetic evaluation were collected up to 48 hours post-dose. The pharmacokinetic parameters were estimated by noncompartmental methods and analyzed as per bioequivalence criteria of statistical analysis. The peak plasma concentration of valsartan was reached with median time of 1 and 3 hours with solution and suspension formulation, respectively. Compared to suspension formulation, the mean peak plasma concentration with solution formulation was higher by 32% (90%CI, 1.27-1.38) while the geometric mean ratios (1.09) and the associated 90%CIs (1.05-1.13) of both the areas under the concentration time-curves (from time zero to the last quantifiable concentration and from time zero to infinity) were contained in the required range of 0.80 to 1.25. No new safety signals were observed with either of the formulations.

Integrated Analytical Quality by Design (AQbD) Approach for the Development and Validation of Bioanalytical Liquid Chromatography Method for Estimation of Valsartan

The present studies describe the systematic development and validation of a simple, rapid, sensitive and cost-effective reversed-phase high-performance liquid chromatographic bioanalytical method for the estimation of valsartan in rat plasma employing analytical quality by design (AQbD) principles quality risk management was applied for identifying the critical method parameters (CMPs) and subsequently method optimization was performed employing Box–Behnken design by selecting mobile phase pH, flow rate and % organic modifier as the CMPs and evaluated for critical analytical attributes (CAAs) such as peak area, retention time, peak tailing and number of theoretical plates. The developed method was then transferred to bioanalysis, where liquid–liquid extraction process was used for separating the drug from rat plasma. The optimization of extraction process was performed with the help of face-centered cubic design by selecting centrifugation speed and centrifugation time as the CMPs for maximizing % recovery, signal-to-noise ratio and purity threshold of the drug peak after extraction as the CAAs. Optimum chromatographic solution was chosen by mathematical and graphical search techniques, and design space was demarcated. Validation studies performed for the developed method indicated linearity ranging between 5 and 100 ng.mL−1, whereas accuracy and precision study showed good percent recovery (99–102%) along with % relative standard deviation within ±2%. Sensitivity evaluation revealed limit of detection and limit of quantification were found to be 0.76 ng.mL−1 and 2.29 ng.mL−1, respectively. In a nutshell, the present work demonstrates significant merits of AQbD approach for holistic process understanding and analytical method development and validation with enhanced robustness and performance.

MOF Capacitates Cyclodextrin to Mega-Load Mode for High-Efficient Delivery of Valsartan

PURPOSE

To investigate the mechanism of enhancing solubility and bioavailability of water-insoluble drug, valsartan (VAL), with being mega-loaded by cyclodextrin metal organic framework (CD-MOF).

METHODS

VAL was successfully mega-loaded into CD-MOF by magnetic agitation of VAL in ethanolic solution. Characterizations including powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), synchrotron radiation-based Fourier transform-infrared spectroscopy (SR-FTIR) ¹³C solid-state nuclear magnetic resonance spectroscopy ( ¹³C SS-NMR), nitrogen gas adsorption, and small-angle X-ray scattering (SAXS) were carried out to confirm the mechanism and incorporation behavior of VAL in CD-MOF. Ball milling process combined with molecular modeling was also used to confirm the mechanism. Improvement of bioavailability in vivo was confirmed by pharmacokinetic experiment in beagles.

RESULTS

As a carrier with payload 150% higher than conventional CD complexation, CD-MOF included molecules of VAL as complexations in the chambers of (γ-CD)₂, and nanoclusters in the confined spherical cages of (γ-CD)₆ confirmed by SAXS and ¹³C SS-NMR. Ball milling combined with molecular modeling inferred that the reduced release rate of the milled CD-MOF with ultrahigh drug payload was mainly due to the partial aggregation of the VAL nanoclusters. The molecules of VAL as nanoclusters in the cages of (γ-CD)₆ are critical in dramatically improving the apparent solubility (39.5-fold) and oral bioavailability (1.9-fold) of VAL in contrast to γ-CD inclusion.

CONCLUSIONS

The new understanding of drug nanoclusters in CD-MOF will help to design more efficient drug delivery systems using CD-MOF carrier with nanocavities.