A practical gas chromatography flame ionization detection method for the determination of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane in silicone emulsions.

A gas chromatography with flame ionization detection (GC-FID) method for analysis of D4, D5, and D6 cyclic siloxanes in silicone emulsions is described. Sample preparation involves breaking the emulsion with methanol and hexanes, and then analyzing the hexanes phase after derivatization with hexamethyldisilazane (HMDS). Silylation is performed to reduce the potential for formation of cyclic siloxanes during the course of the GC analysis.

A new method for measurement of (-)-sophocarpine, a candidate therapeutic for viral myocarditis, in plasma: application to a toxicokinetic study in beagle dogs.

The naturally occurring alkaloid (-)-sophocarpine (SC) has been developed as a novel anti-coxsackieviral agent for potential treatment of viral myocarditis. However, there is currently no rapid, sensitive method available for ascertaining systemic exposure during the course of SC toxicity studies. The development and full validation of the first rapid and sensitive method, based on liquid chromatography with tandem mass spectrometry (LC/MS/MS), for determination of SC in plasma is reported here.

Liquid chromatography/tandem mass spectrometry for the determination of fluoxetine and its main active metabolite norfluoxetine in human plasma with deuterated fluoxetine as internal standard.

Fluoxetine (F) and its N-demehylated metabolite norfluoxetine (NF) are selective inhibitors of serotonin reuptake in humans. A new sensitive rapid method for the simultaneous determination of F and NF in plasma was established and validated, and was further applied to assess the bioequivalence of two oral formulations of F in 22 healthy Chinese male volunteers who received a single oral dose of each formulation (containing 20 mg of fluoxetine hydrochloride). The new method involves using liquid chromatography/tandem mass spectrometry (LC/MS/MS) in multiple reaction monitoring mode with deuterated fluoxetine (DF) as internal standard.