Biotransformation and disposition characteristics of HSK7653, a novel long-acting dipeptidyl peptidase-4 inhibitor for the treatment of type 2 diabetes.

AIM: To investigate the metabolism and disposition characteristics of HSK7653 in healthy male Chinese participants. METHODS: A single oral dose of 80 µCi (25 mg) [14C]HSK7653 capsules was administered to six healthy participants, and blood, plasma, urine and faeces were collected. Quantitative and qualitative analysis was conducted to investigate the pharmacokinetics, blood-to-plasma ratio, mass balance and metabolism of HSK7653. RESULTS: The drug was well absorbed and reached a maximum concentration at 1.25 h. The drug-related components (HSK7653 and its metabolites) were eliminated slowly, with a half-life (t1/2) of 111 h. Unchanged HSK7653 contributed to more than 97% of the total radioactivity in all plasma samples. The blood-to-plasma ratio (0.573-0.845) indicated that HSK7653 did not tend to distribute into blood cells. At 504 h postdose, up to 95.9% of the dose was excreted, including 79.8% in urine and 16.1% in faeces. Most of the radioactivity (75.5% dose) in excreta was unchanged HSK7653. In addition, nine metabolites were detected in urine and faeces. The most abundant metabolite was M6-2, a dioxidation product of HSK7653, which accounted for 4.73% and 2.63% of the dose in urine and faeces, respectively. The main metabolic pathways of HSK7653 in vivo included oxidation, pyrrole ring opening and sulphonamide hydrolysation. CONCLUSION: HSK7653 was well absorbed, slightly metabolized and slowly excreted in humans. The high plasma exposure and long t1/2 of HSK7653 may contribute to its long-lasting efficacy as a long-acting dipeptidyl peptidase-4 inhibitor.

A model based on machine learning for the prediction of cyclosporin A trough concentration in Chinese allo-HSCT patients.

BACKGROUND: Cyclosporin A is a calcineurin inhibitor which has a narrow therapeutic window and high interindividual variability. Various population pharmacokinetic models have been reported; however, professional software and technical personnel were needed and the variables of the models were limited. Therefore, the aim of this study was to establish a model based on machine learning to predict CsA trough concentrations in Chinese allo-HSCT patients. METHODS: A total of 7874 cases of CsA therapeutic drug monitoring data from 2069 allo-HSCT patients were retrospectively included. Sequential forward selection was used to select variable subsets, and eight different algorithms were applied to establish the prediction model. RESULTS: XGBoost exhibited the highest prediction ability. Except for the variables that were identified by previous studies, some rarely reported variables were found, such as norethindrone, WBC, PAB, and hCRP. The prediction accuracy within ±30% of the actual trough concentration was above 0.80, and the predictive ability of the models was demonstrated to be effective in external validation. CONCLUSION: In this study, models based on machine learning technology were established to predict CsA levels 3-4 days in advance during the early inpatient phase after HSCT. A new perspective for CsA clinical application is provided.

Development of Physiology Based Pharmacokinetic Model to Predict the Drug Interactions of Voriconazole and Venetoclax.

PURPOSE: Venetoclax (VEN), an anti-tumor drug that is a substrate of cytochrome P450 3A enzyme (CYP3A4), is used to treat leukemia. Voriconazole (VCZ) is an antifungal medication that inhibits CYP3A4. The goal of this study is to predict the effect of VCZ on VEN exposure. METHOD: Two physiological based pharmacokinetics (PBPK) models were developed for VCZ and VEN using the bottom-up and top-down method. VCZ model was also developed to describe the effect of CYP2C19 polymorphism on its pharmacokinetics (PK). The reversible inhibition constant (Ki) of VCZ for CYP3A4 was calibrated using drug-drug interaction (DDI) data of midazolam and VCZ. The clinical verified VCZ and VEN model were used to predict the DDI of VCZ and VEN at clinical dosing scenario. RESULT: VCZ model predicted VCZ exposure in the subjects of different CYP2C19 genotype and DDI related fold changes of sensitive CYP3A substrate with acceptable prediction error. VEN model can capture PK of VEN with acceptable prediction error. The DDI PBPK model predicted that VCZ increased the exposure of VEN by 4.5-9.6 fold. The increase in VEN exposure by VCZ was influenced by subject's CYP2C19 genotype. According to the therapeutic window, VEN dose should be reduced to 100 mg when co-administered with VCZ. CONCLUSION: The PBPK model developed here could support individual dose adjustment of VEN and DDI risk assessment. Predictions using the robust PBPK model confirmed that the 100 mg dose adjustment is still applicable in the presence of VCZ with high inter-individual viability.

Image edge detection based on singular value feature vector and gradient operator.

This paper presents an edge detection algorithm based on singular value eigenvector and gradient operator. In the proposed algorithm, the singular values of image blocks are first calculated, and the Sobel gradient template is extended to eight other directions. Then the gradient values of image pixels are determined according to the stability of the singular values of image blocks. The determination of gradient threshold is considered from both global and local aspects. After calculating the global and local gradient thresholds of the original image, the gradient threshold of the whole image is determined by weighting function. Then the edge pixels of the image are filtered according to the gradient threshold, and the edge information image of the original image is obtained. The experimental data show that the proposed algorithm can resist a certain degree of noise interference, and the accuracy and efficiency of edge extraction are better than other similar algorithms.

A stochasticlocation privacy protection scheme for edge computing.

Location-based Service has become the fastest growing activity related service that people use in their daily life due to the boom of location-aware mobile devices. In edge computing along with the benefits brought by LBS, privacy preservation becomes a more challenging issue because of the nature of the paradigm, in which peers may cooperate with each other to collect and analyze user's location data. To avoid potential information leakage and usage, user's exact location should not be exposed to the edge node. In this paper, we propose a stochastic location privacy protection scheme for edge computing, in which the geographical distribution of surrounding users is obtained by analyzing proposed long-term density map and short-term density map. The cloaking scheme transfers user's exact location to a cloaked location to satisfy predefined probability of having k-users in that area. Our scheme does not reveal any exact location information, thus it is practicable for the real scenario when edge computing is honest but curious. Extensive experimental results are conducted to verify the efficiency and effectiveness of our method. By varying the privacy protection requirements, the corresponding performance have been examined and discussed.

Theory-based pharmacokinetics and pharmacodynamics of S- and R-warfarin and effects on international normalized ratio: influence of body size, composition and genotype in cardiac surgery patients.

AIMS: The aims of this study are to apply a theory-based mechanistic model to describe the pharmacokinetics (PK) and pharmacodynamics (PD) of S- and R-warfarin. METHODS: Clinical data were obtained from 264 patients. Total concentrations for S- and R-warfarin were measured by ultra-high performance liquid tandem mass spectrometry. Genotypes were measured using pyrosequencing. A sequential population PK parameter with data method was used to describe the international normalized ratio (INR) time course. Data were analyzed with NONMEM. Model evaluation was based on parameter plausibility and prediction-corrected visual predictive checks. RESULTS: Warfarin PK was described using a one-compartment model. CYP2C9 *1/*3 genotype had reduced clearance for S-warfarin, but increased clearance for R-warfarin. The in vitro parameters for the relationship between prothrombin complex activity (PCA) and INR were markedly different (A = 0.560, B = 0.386) from the theory-based values (A = 1, B = 0). There was a small difference between healthy subjects and patients. A sigmoid Emax PD model inhibiting PCA synthesis as a function of S-warfarin concentration predicted INR. Small R-warfarin effects was described by competitive antagonism of S-warfarin inhibition. Patients with VKORC1 AA and CYP4F2 CC or CT genotypes had lower C50 for S-warfarin. CONCLUSION: A theory-based PKPD model describes warfarin concentrations and clinical response. Expected PK and PD genotype effects were confirmed. The role of predicted fat free mass with theory-based allometric scaling of PK parameters was identified. R-warfarin had a minor effect compared with S-warfarin on PCA synthesis. INR is predictable from 1/PCA in vivo.

[Association between CYP2C9 and VKORC1 genetic polymorphism and warfarin dose requirements].

OBJECTIVE: To assess the contribution of vitamin K epoxide reductase complex 1 (VKORC1) and cytochrome P450 2C9 (CYP2C9) genotype, age, body size, height, and weight to warfarin dose requirement. METHODS: Blood samples were collected from 191 patients receiving warfarin therapy. Patients's age, gender, height, and weight were registered. PCR-RFLP method was used for the detection of VKORC1-1639G > A and CYP2C9 genotype. RESULTS: VKORC1-1639G > A genotyping showed that 159 patients were homozygous AA, 31 were heterozygous GA, and 1 was homozygous GG genotype. CYP2C9 genotyping showed that 176 patients were *1/*1, 15 patients were heterozygous *1/*3. Patients with VKORC1-1639 (G > A) GG + GA genotype required a significantly higher warfarin dose than those with AA genotype [(3.36 +/- 0.97) mg/d vs. (1.75 +/- 0.56) mg/d, P < 0.01], and patients with CYP2C9*1/*1 genotype also required a higher warfarin dose than those with CYP2C9*1/*3 genotype [(2.06 +/- 0.83) mg/d vs. (1.55 +/- 1.32) mg/d, P < 0.05]. The multiple linear regression model for warfarin dose indicated age, weight and VKORC1 genotype could explain the inter-individual variation in dose requirement of 9.3%, 7.4%, 51.9% patients, respectively; age, weight, CYP2C9 and VKORC1 genotype together could explain the inter-individual variation in dose requirement of 64.1% patients. CONCLUSION: This study showed that age, weight and VKORC1 and CYP2C9 polymorphism had significant influences on warfarin dose requirements and should be considered on dosing regimens modification to improve the safety of warfarin therapy.

Association study of ABCB1 and CYP3A5 gene polymorphisms with sirolimus trough concentration and dose requirements in Chinese renal transplant recipients.

The objective of this study was to investigate the possible association of the ABCB1 gene C3435 T polymorphism and the CYP3A5 gene A6986G polymorphism with sirolimus (SRL) trough concentration and dose requirements in Chinese stable renal transplant recipients. Blood samples were collected from 105 healthy volunteers and 50 renal transplant patients, whose polymorphisms of the ABCB1 and CYP3A5 genes were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Plasma concentrations of SRL were determined with HPLC. The allele frequencies of the ABCB1 mutation in Chinese healthy volunteers and renal transplant recipients were 51.0% and 44.0% (p>0.05), while the allele frequencies of the CYP3A5 mutation were 72.9% and 71.0% (p>0.05). The SRL concentration/dose ratio (C/D) in patients with CYP3A5 (*)3/(*)3 were significantly higher than that of those with (*)1 allele (p<0.05). However, no significant differences were observed between C/D and ABCB1 SNPs (p>0.05). These results confirm that when treated with a SRL-based therapy and low-dose steroids, patients carrying the CYP3A5(*)1 allele required significantly more SRL to achieve adequate blood trough concentrations. In patients with SRL-based therapy, genotyping of the CYP3A5 genes may help to optimize the SRL management in renal transplant recipients.

Development and validation of a sensitive quantification method for hematoporphyrin monomethyl ether in plasma using high-performance liquid chromatography with fluorescence detection.

A rapid, sensitive, precise and specific method for determination of hematoporphyrin monomethyl ether (HMME), a novel photodynamic therapy (PDT) drug, was developed and validated using high-performance liquid chromatography (HPLC) with fluorescence detection. HMME was isolated from the plasma by a single-step liquid-liquid extraction with ethyl acetate. The analyte and internal standard fluorescein were baseline separated on a Diamonsil C(18) analytical column (4.6 x 150 mm, 5 microm) and analyzed using a fluorescence detector with the excitation and emission wavelengths set at 395 and 613 nm, respectively. The method was linear in the concentration range 0.025-5 microg/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. The inter- and intra-day accuracies and precisions were all within 10% and the mean recoveries of HMME and fluorescein were 95 +/- 3.7 and 90 +/- 2.3%, respectively. The analyte was stable during all sample storage, preparation and analysis periods. This method was successfully applied to a pharmacokinetic study after a single-dose intravenous administration of HMME (5 mg/kg) to beagle dogs. This method was reproducible and sensitive enough for the pharmacokinetic study of HMME. Based on the results of the pharmacokinetic study, we suggest that a rather long light-avoiding time is essential for patients under HMME therapy.

Development of a HPLC-MS assay for ginsenoside Rh2, a new anti-tumor substance from natural product and its pharacokinetic study in dogs.

To develop a HPLC-MS method of determining ginsenoside Rh2 in dog plasma based on solid-phase extraction for pharmacokinetic studies. Six dogs were randomly assigned to two groups, either given 0.1 mg/kg dose intravenously or 1 mg/kg dose through oral gavage. Analysis using high performance liquid chromatography (HPLC) with ODS column, followed by detection with electrospray ionization(ESI) mass spectrometry(MS) in negative ion mode with 500 microM ammonium chloride in the mobile phase. The assays were validated over the concentration range of 2.0-1250.0 ng/ml in dog plasma. The intra- and inter- day precision were less than 10% in terms of RSD. The overall recovery was more than 80%. The validated assay was suitable for pharmacokinetic studies of ginsenoside Rh2 and the observed oral bioavailabilities of Rh2 were 17.6% and 24.8% for male and female dogs respectively.

Uptake and metabolism of ginsenoside Rh2 and its aglycon protopanaxadiol by Caco-2 cells.

The uptake and metabolism profiles of ginsenoside Rh2 and its aglycon protopanaxadiol (ppd) were studied in the human epithelial Caco-2 cell line. High-performance liquid chromatography-mass spectrometry was applied to determine Rh2 and its aglycon ppd concentration in the cells at different pH, temperature, concentration levels and in the presence or absence of inhibitors. Rh2 uptake was time and concentration dependent, and its uptake rates were reduced by metabolic inhibitors and influenced by low temperature, thus indicating that the absorption process was energy-dependent. Drug uptake was maximal when the extracellular pH was 7.0 for Rh2 and 8.0 for ppd. Rh2 kinetic analysis showed that a non-saturable component (Kd 0.17 nmol x h(-1) x mg(-1) protein) and an active transport system with a Km of 3.95 micromol x l(-1) and a Vmax of 4.78 nmol x h(-1) x mg(-1)protein were responsible for the drug uptake. Kinetic analysis of ppd showed a non-saturable component (Kd 0.78 nmol x h(-1) x mg(-1) protein). It was suggested that active extrusion of P-glycoprotein and drug degradation in the intestine may influence Rh2 bioavailability.