The study aims to evaluate the bioequivalence of valsartan hydrochlorothiazide tablets, and to investigate the potential cause of bioinequivalence. This was a single-center study with an open, randomized double-way crossover design. Test and reference preparations containing 160 mg of valsartan and 25 mg of hydrochlorothiazide were given to 36 healthy male volunteers. Plasma concentrations of valsartan and hydrochlorothiazide were determined simultaneously by LC-MS/MS. The pharmacokinetic parameters and relative bioavailability were calculated, while the bioequivalence between test and reference preparations were evaluated. The dissolution profiles of test and reference preparations in four different mediums were determined via dissolution test and HPLC. The similarity was investigated according to the similarity factors (f2). The F(o-t) and F(0-infinity) were (139.4 +/- 65.2)% and (137.5 +/- 61.2)% for valsartan of test preparations. It led to get the conclusion that test and reference preparations were not bioequivalent for valsartan. A significant difference was observed between test and reference tablets in the valsartan dissolution test of pH 1.2 hydrochloric acid solution. The key factor of the bioinequivalence might be that dissolution of valsartan in acid medium has marked difference between two preparations.
Administration, Oral ; Adolescent ; Adult ; Angiotensin II Type 1 Receptor Blockers ; administration & dosage ; adverse effects ; blood ; pharmacokinetics ; Antihypertensive Agents ; administration & dosage ; adverse effects ; blood ; pharmacokinetics ; Area Under Curve ; Chromatography, Liquid ; Cross-Over Studies ; Drug Liberation ; Humans ; Hydrochlorothiazide ; administration & dosage ; adverse effects ; blood ; pharmacokinetics ; Male ; Tablets ; Tandem Mass Spectrometry ; Therapeutic Equivalency ; Valsartan ; administration & dosage ; adverse effects ; blood ; pharmacokinetics ; Young Adult

The study aims to evaluate the bioequivalence of valsartan hydrochlorothiazide tablets, and to investigate the potential cause of bioinequivalence. This was a single-center study with an open, randomized double-way crossover design. Test and reference preparations containing 160 mg of valsartan and 25 mg of hydrochlorothiazide were given to 36 healthy male volunteers. Plasma concentrations of valsartan and hydrochlorothiazide were determined simultaneously by LC-MS/MS. The pharmacokinetic parameters and relative bioavailability were calculated, while the bioequivalence between test and reference preparations were evaluated. The dissolution profiles of test and reference preparations in four different mediums were determined via dissolution test and HPLC. The similarity was investigated according to the similarity factors (f2). The F(o-t) and F(0-infinity) were (139.4 +/- 65.2)% and (137.5 +/- 61.2)% for valsartan of test preparations. It led to get the conclusion that test and reference preparations were not bioequivalent for valsartan. A significant difference was observed between test and reference tablets in the valsartan dissolution test of pH 1.2 hydrochloric acid solution. The key factor of the bioinequivalence might be that dissolution of valsartan in acid medium has marked difference between two preparations.

A rapid, sensitive and convenient LC-MS/MS method was developed for the determination of γ-aminobutyric acid (GABA) in human plasma. d2-γ-Aminobutyric acid (d2-GABA) was synthesized as internal standard (IS). After extraction from human plasma by protein precipitation with acetonitrile, all analytes were separated on a Luna HILIC column (100 mm x 3.0 mm, 3 μm) using an isocratic mobile phase of water: acetonitrile: formic acid (20 : 80 : 0.12) with a flow rate of 0.5 mL x min(-1). Acquisition of mass spectrometric data was performed in multiple reaction monitoring mode (MRM) in positive electrospray ionization using the transitions of m/z 104 --> 69 for GABA and m/z 106 --> 71 for d2-GABA. The method was linear in the concentration range of 5.00 to 1 000 ng x mL(-1). The intra- and inter-day precisions were within 9.9%, and accuracy ranged from 99.1% to 104%, within the acceptable limit across all concentrations. The method was successfully applied to a pharmacokinetic study of GABA tablets in healthy Chinese volunteers.
Chromatography, Liquid ; Humans ; Tandem Mass Spectrometry ; gamma-Aminobutyric Acid ; blood

To study the metabolite excretion of theophylline, a rapid and specific method by liquid chromatography with heated electrospray ionization tandem mass spectrometry (LC-HESI/MS/MS) method for simultaneous determination of theophylline, 1, 3-dimethyluric acid (1,3-DMU), 3-methylxanthine (3-MX) and 1-methyluric acid (1-MU) in human urine was developed using theophylline-d6 and 5-fluorouracil as internal standards. Selected reaction monitoring (SRM) with heated electrospray ionization (HESI) was used in the negative mode for mass spectrometric detection. After diluted with methanol and centrifuged, the analytes and ISs were separated on a XDB-Phenyl (150 mm x 4.6 mm, 5 microm) column with a mixture of water-methanol-formic acid (30 : 70 : 0.15) as mobile phase at a flow rate of 0.6 mL x min(-1). The linear calibration curves for theophylline, 1, 3-DMU, 3-MX and 1-MU were obtained in the concentration range of 1.0-250 microg x mL(-1), separately. The method herein described is effective and convenient, and can be used for determination of theophylline and its three metabolites. The results showed that urinary excretion ratio of theophylline, 1,3-DMU, 3-MX and 1-MU is approximately 1 : 3 : 1 : 2 in Chinese subjects, which is similar to the reported excretion pattern in Caucasian.
Administration, Oral ; Asian Continental Ancestry Group ; Calibration ; Chromatography, Liquid ; Delayed-Action Preparations ; metabolism ; Healthy Volunteers ; Humans ; Spectrometry, Mass, Electrospray Ionization ; Tablets ; Tandem Mass Spectrometry ; Theophylline ; metabolism ; urine ; Uric Acid ; analogs & derivatives ; urine ; Xanthines ; urine

Humans ; Moxibustion ; Depression ; Acupuncture Therapy ; Gastroesophageal Reflux ; Esophagitis, Peptic

A chiral LC-MS/MS method for the simultaneous analysis of desvenlafaxine (DVS) enantiomers in human plasma was developed and applied to a pharmacokinetic study on 12 Chinese healthy volunteers. d6-Desvenlafaxine was used as internal standard (IS). Chromatographic separation was performed on the Astec Chirobiotic V chiral column (150 mm x 4.6 mm, 5 μm). The assay was linear over the concentration range of 0.500-150 ng x mL(-1) for both enantiomers (r2 > 0.99). The method was successfully applied to a stereoselective pharmacokinetic study of 100 mg desvenlafaxine sustained release tablets on 12 Chinese healthy volunteers under fasting conditions. The results showed that the pharmacokinetic parameters were similar to both enantiomers in Chinese healthy volunteers. The AUC(0-t), and C(max) of the two enantiomers were about 1.5 times higher than those of blacks and whites reported in the literature.
Administration, Oral ; Area Under Curve ; Asian Continental Ancestry Group ; Chromatography, Liquid ; Cyclohexanols ; blood ; pharmacokinetics ; Delayed-Action Preparations ; Desvenlafaxine Succinate ; Dose-Response Relationship, Drug ; Healthy Volunteers ; Humans ; Male ; Plasma ; chemistry ; Stereoisomerism ; Tablets ; Tandem Mass Spectrometry

This study is to establish physiologically based pharmacokinetic (PBPK) models of famitinib in rat and monkey, and then to predict the pharmacokinetics and tissue distribution of famitinib in human based on the PBPK models. According to published paper, previous studies and the chemical properties of famitinib predicted by ACD/ADME suite and SimCYP, the PBPK models of rat and monkey were established and optimized using GastroPlus. And then, the PBPK models were applied to predict the pharmacokinetic and tissue distribution of famitinib in human. The results showed that the PBPK models of rat and monkey can fit the observed data well, and the AUC0-∞, ratios of observed and calculated data in rat and monkey were 1.00 and 0.97, respectively. The AUC0-∞, ratios of observed and predicted data in human were 1.63 (rat to human) and 1.57 (monkey to human), respectively. The rat and monkey PBPK models of famitinib were well established, and the PBPK models were applied in predicting pharmacokinetic of famitinib in human successfully. Hence, the PBPK model of famitinib in human could be applied in future drug-drug interaction study.
Animals ; Antineoplastic Agents ; pharmacokinetics ; Haplorhini ; Humans ; Indoles ; pharmacokinetics ; Models, Biological ; Pyrroles ; pharmacokinetics ; Rats ; Receptor Protein-Tyrosine Kinases ; antagonists & inhibitors ; pharmacokinetics ; Tissue Distribution

BACKGROUND: Proliferation and differentiation of mesenchymal stem cells (MSCs) is associated with platelet concentration in platelet-rich plasma (PRP). Low enrich multiple cannot reach proper effects, but high level had inhibitory effects on osteoanagenesis.OBJECTIVE: To observe the effect of different volume fraction of PRP on dog BMSC proliferation.DESIGN: A cytological in vitro study.MATERIALS: Healthy 12-month male Beagle dogs were supplied by the Experimental Animal Center, Xiangya Medical College,Central South University.METHODS: Dog BMSCs of 5 passage were adjusted to 3×10~8/L, and incubated in a 96-well plate at 200 μL per well. Following 24 hours of routine culture, primary medium and non-adherent cells were discarded. Prepared PRP gel was mixed with serum-free low-glucose DMEM containing penicillin and streptomycin, and then diluted into 5%, 6.25%, 7.5%, 8.75%, 10% volume fraction. 200 μL above-described liquid was added into the 96-well plate, which was subsequently placed in a incubator.We set up a blank control.MAIN OUTCOME MEASURES: MTT was used to investigate effect of different volume fraction of PRP on dog BMSC proliferation.RESULTS: Compared with the blank control group, various volume fraction of PLP could promote dog BMSC proliferation in early stage. With prolonged time, proliferation speed began to increase at day 6 in the 8.75% and 10% PRP groups, entering platform stage. BMSC number was increased rapidly in the 5% and 6.25% PRP groups, especially in the 6.25% PRP group.CONCLUSION: PRP gel could promote BMSC proliferation markedly and proliferation strength of BMSCs was correlated to the density of PRP. BMSC proliferation would be accelerated by the low density of PRP.

BACKGROUND: Platelet-rich plasma (PRP) contains abundant growth factors that were needed for osteanagenesis. Moreover,the proportion of each growth factor formed by an organism, with good synergism.OBJECTIVE: To explore the influence of PRP on osteogenetic activity of canine bone marrow mesenchymal stem cells (BMSCs) after induction in vitro.DESIGN, TIME AND SETTING: The in vitro cytological experiment was performed at the Central Laboratory of Xiangya Hospital of Central South University from June 2007 to February 2008.MATERIALS: Healthy 12-month male Beagle dogs were supplied by the Experimental Animal Center, Xiangya Medical College,Central South University.METHODS: The 3~(rd) generation BMSCs were collected and divided into 4 groups. BMSCs in the control group were incubated in standard medium. BMSCs in the osteogenetic induction medium group were incubated in high-glucose DMEM containing fetal calf serum, dexamethasone, beta-sodium glycerophosphate and vitamin C. BMSCs in the PRP group were incubated in low-glucose DMEM containing 6.25% PRP. BMSCs in the combination group were incubated in high-glucose DMEM containing 6.25% PRP, dexamethasone, beta-sodium glycerophosphate, and vitamin C.MAIN OUTCOME MEASURES: Alkaline phosphatase activities were measured. Expression of collagen type I was examined by immunocytochemical staining. Calcium tuberoses were labeled using modified Von Kossa staining. Expression of osteocalcin mRNA was examined by RT-PCR.RESULTS: Levels of alkaline phosphates of all groups became increased along with time. The alkaline phosphates level of combination group was strongest (P < 0.05). Following 7 and 14 days of induction, type I collagen expressed positively in the osteogenetic induction medium and combination groups, but negatively in the PRP and control groups. Following 14 days,formation of calcium nodules were found in the osteogenetic induction medium and combination groups. Following 7 and 14 days,expression of osteocalcin mRNA were similar between the control and PRP groups (P > 0.05), which was significantly lower than the osteogenetic induction medium and combination groups (P < 0.05). Expression of osteocalcin mRNA was significantly lower in the osteogenetic induction medium group compared with the combination group (P < 0.05).CONCLUSION: PRP gel can effectively promote osteoblastic effect of BMSCs after induction in vitro following induction in osteogenetic medium.

The study aims to develop a rapid, sensitive and specified method of liquid chromatography with heated electrospray ionization tandem mass spectrometry (LC-HESI/MS/MS) for simultaneous determination of amlodipine, benazepril and benazeprilat in human plasma using amlodipine-d4 and ubenimex as internal standards (ISs). Selected reaction monitoring (SRM) with heated electrospray ionization (HESI) was used in the positive mode for mass spectrometric detection. Analytes and ISs were extracted from plasma by simple protein precipitation. The reconstituted samples were chromatographed on a C18 (100 mm x 4.6 mm, 5 microm) column with mixture of methanol-acetonitrile-5 mmol.L- ammonium acetate-formic acid (30 : 30 : 40 : 0.1) as mobile phase at a flow rate of 0.6 mL.min-1. The standard curves were demonstrated to be linear in the range of 0.02 to 6.00 ng.mL-1 for amlodipine, 0.2 to 1,500 ng.mL-1 for benazepril and benazeprilat with r2>0.99 for each analyte. The lower limit of quantitation was identifiable and reproducible at 0.02, 0.2 and 0.2 ng mL-1 for amlodipine, benazepril and benazeprilat, respectively. The intra-day and inter-day precision and accuracy results were within the acceptable limit across all concentrations. The plasma samples were stable after four freeze-thaw cycles and being stored for 93 days at -20 degrees C. The method was applied to a pharmacokinetic study of a fixed-dose combination of amlodipine and benazepril on Chinese healthy volunteers.
Administration, Oral ; Amlodipine ; administration & dosage ; blood ; Benzazepines ; administration & dosage ; blood ; Chromatography, Liquid ; Humans ; Sensitivity and Specificity ; Spectrometry, Mass, Electrospray Ionization ; Tandem Mass Spectrometry