A rapid, precise, specific, and accurate Electrospray Ionisation Tandem Mass Spectrometry (ESI-MS / MS) method has been developed and subsequently validated, for the determination of pregabalin (PB) in human plasma. Gabapentin (GB) was used as the internal standard. PB and GB were extracted from the plasma using a combination of deproteinization, using 0.1% formic acid and liquid–liquid extraction, using methylene chloride. PB and GB were separated using the Hypurity advance column (50 mm × 4.6 mm, 5 μm) and mobile phase, consisting of methanol : 0.1% formic acid (80:20 v / v). PB was determined by using ESI-MS / MS in positive ion mode, with the help of the API 2000 spectrophotometer, operated in a multiple reaction monitoring mode. The parent-to-product ion combination of m / z 160.2→55.1 and 172.2→95.0 was used to quantify PB and GB, respectively. The assay was validated in the concentration range of 99.79 – 4019.90 ng / mL for PB. The limit of quantification (LOQ) was identifiable and reproducible at 99.79 ng / mL. The method has been successfully applied to study the pharmacokinetics of PB in healthy male volunteers.
BackgroundEvidence is lacking for multi-ingredient herbal supplements claiming therapeutic effect in sexual dysfunction in men. We examined the safety and efficacy of VigRX Plus (VXP) – a proprietary polyherbal preparation for improving male sexual function, in a double blind, randomized placebo-controlled, parallel groups, multi-centre study.Methods78 men aged 25–50 years of age; suffering from mild to moderate erectile dysfunction (ED), participated in this study. Subjects were randomized to receive VXP or placebo at a dose of two capsules twice daily for 12 weeks. The international index of erectile function (IIEF) was the primary outcome measure of efficacy. Other efficacy measures were: Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS), Serum testosterone, Semen analysis, Investigator’s Global assessment and Subjects’ opinion.ResultsIn subjects receiving VXP, the IIEF-Erectile Function (EF) scores improved significantly as compared to placebo. After 12 weeks of treatment, the mean (sd) IIEF-EF score at baseline increased from 16.08 (2.87) to 25.08 (4.56) in the VXP group versus 15.86 (3.24) to 16.47 (4.25) in the placebo group (P < 0.0001). Similar results were observed in each of the remaining four domains of the IIEF (orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction).There was a significant difference for VXP versus placebo comparison of mean (sd) EDITS scores of patients: 82.31(20.23) vs 36.78(22.53) and partners :(82.75(9.8) vs 18.50(9.44);P < 0.001. Thirty-five out of 39 (90%) subjects from the VXP group and one (3%) from the placebo group wished to continue with the treatment they received. Investigator’s global assessment rated VXP therapy as very good to excellent in more than 50% patients and placebo therapy as fair to good in about 25% of patients. Incidence of side effects and subject’s rating for tolerability of treatment was similar in both groups.ConclusionsVigRX Plus was well tolerated and more effective than placebo in improving sexual function in men.Trial RegistrationClinical Trial Registry India, CTRI/2009/091/000099, 31-03-2009
A simple, sensitive and selective liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the analysis of venlafaxine (VX) and its major active metabolite O-desmethyl venlafaxine (ODV) in rat plasma using carbamazepine as an internal standard (IS). The analytes from the biological matrix were extracted by liquid-liquid extraction using tert-butyl methyl ether (TBME). The HPLC separation of the analytes was performed on a water symmetry C18 (150 × 4.6 mm i.d., 5 µm) column, using a 10 mM ammonium formate:methanol (20:80 v/v) as mobile phase. The calibration curve concentration range was 10.10 to 8000.00 ng/mL for VX and ODV with coefficient of determination above 0.9970. The lower limit of quantification (LLOQ) of VX and ODV were 3.35 and 3.86 ng/mL, respectively. The intra-and inter-day coefficients of variation were within 15%.
Context Selective deficiency of β‐subunit of luteinizing hormone (LHB) is a rare disease with scarce data on its characteristics. Objectives To describe a male with LHB deficiency and systematically review the literature. Design and Patients Description of a male patient with LHB deficiency and a systematic review of LHB deficiency patients published to date (10 males and 3 females) as per PRISMA guidelines. Results A 36‐year‐old Asian Indian male presented with infertility. On evaluation, he had sexual maturity of Tanner's stage 3, low testosterone (0.23 ng/ml), low LH (0.44 mIU/ml), high follicle‐stimulating hormone (FSH, 22.4 mIU/ml), and a novel homozygous missense likely pathogenic variant (p.Cys46Arg) in LHB. In the molecular dynamics simulation study, this variant interferes with heterodimerization of alpha‐beta subunits. Eleven males with pathogenic variants in LHB reported to date, presented at a median age of 29 (17–38) years, most commonly with delayed puberty. Clinical and biochemical profiles were similar to those of our patient. In the majority, testosterone monotherapy modestly increased testicular volume whereas human chorionic gonadotropin (hCG) monotherapy also improved spermatogenesis. In females, oligomenorrhoea after spontaneous menarche was the most common manifestation. Ten pathogenic/likely pathogenic variants (three in‐frame deletions, three missense, two splice‐site, one nonsense, and one frameshift variants) have been reported in nine index patients. Conclusion We report a novel likely pathogenic LHB variant in an Asian Indian patient. The typical phenotype in male patients with LHB deficiency is delayed puberty with low testosterone, low LH, and normal to high FSH and hCG monotherapy being the best therapeutic option.
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