A sensitive assay for ZYAN1 in human whole blood and urine utilizing positive LC-MS/MS electrospray ionization.

AIM: A sensitive LC-MS/MS method was developed and validated for estimation of ZYAN1 in human blood/urine. METHODS: An analog internal standard IOX2 along with ZYAN1 was quantified using selective reaction monitoring in positive mode. The chromatographic separation was performed by gradient elution with C18 analytical column (3 µm, 50 mm × 2.0 mm) with 4-min run time using an acidified mobile phase consisting of ammonium formate and acetonitrile. Protein precipitation enabled extraction of analytes from diluted blood/urine. RESULTS: Calibration curve of ZYAN1 was linear (2-5000 ng/ml). The recovery of ZYAN1 and IOX2 was between 87 and 104%. Interday and intraday accuracy and precision was found well within the acceptance criteria. CONCLUSION: The validated assay was applied for clinical pharmacokinetics of ZYAN1 in healthy volunteers.

Characterization of the key aroma compounds in Shiraz wine by quantitation, aroma reconstitution, and omission studies.

The key aroma compounds of premium Australian Shiraz wines from the warm Barossa Valley and cooler Margaret River regions were characterized. GC-Olfactometry was conducted to determine the most important volatile compounds, which were then quantitated. The wine from the Barossa Valley had higher concentrations of ethyl propanoate, dimethyl sulfide (DMS), and oak-derived compounds, whereas the Margaret River wine contained above threshold concentrations of the 'cheesy' compounds 2- and 3-methylbutanoic acid, as well as rotundone, the 'pepper'-smelling compound. The aromas were reconstituted by combining 44 aroma compounds, and sensory descriptive analysis was used to investigate the importance of the omission of several compounds, including DMS, rotundone, fatty acids, and ß-damascenone, and the influence of nonvolatiles was also assessed. The study showed that the aroma of the Shiraz wines could be reconstituted in both cases, with the changes in the nonvolatile fraction having a large influence.

Contribution of several volatile phenols and their glycoconjugates to smoke-related sensory properties of red wine.

Guaiacol and 4-methylguaiacol are well-known as contributors to the flavor of wines made from smoke-affected grapes, but there are other volatile phenols commonly found in smoke from forest fires that are also potentially important. The relationships between the concentration of a range of volatile phenols and their glycoconjugates with the sensory characteristics of wines and model wines were investigated. Modeling of the attribute ratings from a sensory descriptive analysis of smoke-affected wines with their chemical composition indicated the concentrations of guaiacol, o-cresol, m-cresol, and p-cresol were related to smoky attributes. The best-estimate odor thresholds of these compounds were determined in red wine, together with the flavor threshold of guaiacol. Guaiacol ß-D-glucoside and m-cresol ß-D-glucoside in model wine were found to give rise to a smoky/ashy flavor in-mouth, and the respective free volatiles were released. The study indicated that a combination of volatile phenols and their glycosides produces an undesirable smoke flavor in affected wines. The observation of flavor generation from nonvolatile glycoconjugates in-mouth has potentially important implications.

Pharmacokinetics of fentanyl after subcutaneous administration in volunteers.

BACKGROUND AND OBJECTIVE: Pain relief using intermittent subcutaneous injections of an opioid (e.g. morphine) avoids the need for venous access and does not require complex or expensive pumps and devices. Although data on the pharmacokinetics of subcutaneous morphine exist, there are no comparable data for fentanyl in healthy volunteers. Therefore, the aim of this study was to characterize the pharmacokinetics of 200 microg fentanyl administered as a single bolus dose via the subcutaneous route in healthy opioid-naive volunteers. METHODS: Nine healthy male volunteers were given 200 microg of subcutaneous fentanyl for more than 30 s. Opioid effects were blocked by administration of naltrexone. Venous blood samples taken at intervals from 5 min to 10 h after the dose were assayed using a liquid chromatography-mass spectrometry method. Pharmacokinetic data were analysed using a noncompartmental analysis approach. RESULTS: After subcutaneous bolus dose administration, the median maximum concentration of fentanyl was 0.55 ng ml(-1) (range 0.28-0.87 ng ml(-1)), reached at a median time of 15 min (range 10-30 min). The terminal half-life was 10.00 h (range 5.48-16.37 h). CONCLUSION: Absorption of subcutaneous fentanyl was relatively rapid and similar to the rate of absorption previously reported for subcutaneous morphine; the terminal half-life for fentanyl was substantially longer (10 h) than that of morphine (2.1 h), and blood concentrations were no more variable than that after administration by other nonintravenous routes.

Pharmacokinetics and bioequivalence evaluation of two fixed-dose tablet formulations of dihydroartemisinin and piperaquine in Vietnamese subjects.

The two fixed-dose combinations of dihydroartemisinin and piperaquine (Artekin and Arterakine) were found to be bioinequivalent in healthy Vietnamese subjects. However, because the peak plasma concentrations and areas under the concentration-time curves of dihydroartemisinin and piperaquine were only marginally different between the two formulations, similar therapeutic efficacies are expected in the treatment of malaria infections.

Coordination and fluorescence of the intracellular Zn2+ probe [2-methyl-8-(4-toluenesulfonamido)-6-quinolyloxy]acetic acid (Zinquin A) in ternary Zn2+ complexes.

A potentiometric study of the coordination of the fluorophore, 2-methyl-8-(4-toluenesulfonamido)-6-quinolyloxyacetic acid, (1)LH(2) (the intracellular Zn(2+) probe, Zinquin A) in its deprotonated form, (1)L(2)(-), in Zn(2+) ternary complexes, [Zn(n)L(1)L](n) (where n is the charge of (n)L) at 298.2 K in 50% aqueous ethanol (v/v) and I = 0.10 (NaClO(4)), shows that the formation of [Zn(n)L(1)L](n) from [Zn(n)L]((2+)(n)(+) is characterized by log(K(5)/dm(3) mol(-1)) = 8.23 +/- 0.05, 4.36 +/- 0.18, 8.45 +/- 0.10, 10.00 +/- 0.06, 11.53 +/- 0.06 and 5.92 +/- 0.15, respectively, where (n)L = (2)L - (6)L and (7)L(3-) are 1,4,7,10-tetraazacyclododecane, 1,4,8,11-tetraazacyclotetradecane, 1,4,7-triazacyclononane, 1,5,9-triazacyclododecane, tris(2-aminoethyl)amine and nitrilotriacetate, respectively, and K(5) is the stepwise complexation constant. Dissociation of a hydroxo proton from triethanolamine, (8)L, occurs in the formation of [Zn(8)LH(-1)](+) that subsequently forms [Zn(8)LH(-1)(1)L](-) for which log(K(5)/dm(3) mol(-1)) = 9.87 +/- 0.08. The variation of K(5) and the 5-fold variation of quantum yield of (1)L(2)(-) as its coordination environment changes in Zn(2+) ternary complexes are discussed with reference to the use of (1)L(2-) in the detection of intracellular Zn(2+).