Maraviroc is a first-in-class CCR5 antagonist that shows potent anti-HIV-1 activity in vitro and in vivo and is well tolerated in both healthy volunteers and HIV-1-infected patients. The method for determination of maraviroc (UK-427,857) and its major metabolite (UK-408,027) in human plasma consists of a protein-precipitation procedure and analysis by liquid chromatography/tandem mass spectrometry using positive ion TurboIonSpray® ionization and multiple reaction monitoring. The assay has been validated over a concentration range of 0.500-500 ng/mL for both analytes. The determinations of maraviroc in human cerebrospinal fluid (0.500-500 ng/mL) and in urine (5.00-5000 ng/mL) have also been validated but do not include measurement of the metabolite. The validations included extraction recovery, intra-assay and inter-assay precision and accuracy, stability of stock and spiking solutions, freeze-thaw stability, matrix stability, processed-extract stability, and evaluation of potential interferences from selected medications in plasma or urine.

Basic chemical processes in a CF 4/°2 plasma during etching of silicon nitride have been investigated using mass spectrometry. Samples of the discharge are extracted through a quartz capillary and the resulting variations in species abundance at a nitride/oxide interface yield information on etch reaction pathways. Mechanisms ofF and CP2 attack and SiF 4 , N 2 , NO, and CN product formation are proposed. The experimental data are suitable for application in mass spectrometric endpoint detection.

The emission of Si, SiCl, Cl, CIl' CCl, Cl + , and Cl i has been observed in a CC1 4 rf disc harge in the presence ofSi( 100) in a plasma etching system. Spectral intensities have been recorded over a wide range of process gas flow rates and rf powers. These data have been analyzed to show that (i) SiCl emission from the A state arises through chemiluminescent reactions of metastable (J S) Si and (ii) the species which leaves the Si surface in the etching process is SiCl", (x = 0, 1, or 2) rather than SiC1 3 or SiCI 4 • To arrive at these conclusions, detailed chemical models are examined and shown quantitatively to reproduce our observed variations of emission with flow and power.