The oral tyramine pressor test was administered to healthy males during treatment with a selegiline transdermal system (STS; 6 mg/24 h). The tyramine sensitivity factor (TSF) was calculated from the ratio of baseline and on-treatment tyramine pressor doses. The tyramine sensitivity factor value following 9 days of treatment with the selegiline transdermal system was 1.85 +/- 0.10. Extended treatment, 33 days, produced a small, clinically non-meaningful increase in this value. The tyramine sensitivity factor for the selegiline transdermal system was similar to that following treatment with 10 mg/d of oral selegiline capsules but more than 20 times less than observed during tranylcypromine treatment. A larger increase in the tyramine sensitivity factor was observed following extended selegiline transdermal system treatment at a higher dose (12 mg/24 h), which was significantly decreased following coadministration of tyramine capsules with a meal. These results suggest a wide tyramine safety margin for the selegiline transdermal system and provide evidence that the 6-mg/24-h selegiline transdermal system can be administered safely without dietary tyramine restrictions.
To-date, there has been no effective chiral capillary electrophoresis-mass spectrometry (CE-MS) method reported for the simultaneous enantioseparation of the antidepressant drug, venlafaxine (VX) and its structurally-similar major metabolite, O-desmethylvenlafaxine (O-DVX). This is mainly due to the difficulty of identifying MS compatible chiral selector, which could provide both high enantioselectivity and sensitive MS detection. In this work, poly-sodium N-undecenoyl-L,L-leucylalaninate (poly-L,L-SULA) was employed as a chiral selector after screening several dipeptide polymeric chiral surfactants. Baseline separation of both O-DVX and VX enantiomers was achieved in 15 min after optimizing the buffer pH, poly-L L-SULA concentration, nebulizer pressure and separation voltage. Calibration curves in spiked plasma (recoveries higher than 80%) were linear over the concentration range 150–5,000 ng/mL for both VX and O-DVX. The limit of detection (LOD) was found to be as low as 30 ng/mL and 21 ng/mL for O-DVX and VX, respectively. This method was successfully applied to measure the plasma concentrations of human volunteers receiving VX or O-DVX orally when co-administered without and with indinivar therapy. The results suggest that micellar electrokinetic chromatography electrospray ionization-tandem mass spectrometry (MEKC-ESI-MS/MS) is an effective low cost alternative technique for the pharmacokinetics and pharmacodynamics studies of both O-DVX and VX enantiomers. The technique has potential to identify drug-drug interaction involving VX and O-DVX enantiomers while administering indinivar therapy.
The hCG test is a valid indicator of the presence of functioning testicular tissue. It is predictive of anorchia and a good response to hCG suggests the presence of testes sufficiently large for orchidopexy.
The selegiline transdermal system is a monoamine oxidase inhibitor that was recently approved by the US Food and Drug Administration for the treatment of major depressive disorder. The current study was conducted during the selegiline transdermal system development program to characterize the single-dose pharmacokinetics and absolute bioavailability of selegiline administered by the 6-mg/24-h selegiline transdermal system in healthy volunteers. Selegiline transdermal system results were compared with those obtained after a single 10-mg oral dose of selegiline HCl. The selegiline pharmacokinetics differed greatly between the 2 routes of administration. Transdermal selegiline administration reduced metabolism and produced a high, sustained plasma selegiline concentration over the dosing period, with an absolute bioavailability of 73%. By contrast, oral dosing produced a sharp plasma selegiline peak that occurred within 1 hour and declined rapidly, with an absolute bioavailability of 4%. The data provide the basis for therapeutic advantages of the selegiline transdermal system in administering antidepressant doses of selegiline.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.