Related Articles A generic static headspace gas chromatography method for determination of residual solvents in drug substance. J Chromatogr A. 2010 Aug 13; Authors: Cheng C, Liu S, Mueller BJ, Yan Z In order to increase productivity of drug analysis in the pharmaceutical industry, an efficient and sensitive generic static headspace gas chromatography (HSGC) method was successfully developed and validated for the determination of 44 classes 2 and 3 solvents of International Conference of Harmonization (ICH) guideline Q3C, as residual solvents in drug substance. In order to increase the method sensitivity and efficiency in sample equilibration, dimethylsulfoxide (DMSO) was selected as the sample diluent based on its high capacity of dissolving drug substance, stability and high boiling point. The HS sample equilibration temperature and equilibration time are assessed in ranges of 125-150 degrees C and 8-15min, respectively. The results indicate that the residual solvents in 200mg of drug substance can be equilibrated efficiently in HS sampler at 140 degrees C for 10min. The GC parameters, e.g. sample split ratio, carrier flow rate and oven temperature gradient are manipulated to enhance the method sensitivity and separation efficiency. The two-stage gradient GC run from 35 to 240 degrees C, using an Agilent DB-624 capillary column (30m long, 0.32mm I.D., 1.8mum film thickness), is suitable to determine 44 ICH classes 2 and 3 solvents in 30min. The method validation results indicate that the method is accurate, precise, linear and sensitive for solvents assessed. The recoveries of most of these solvents from four drug substances are greater than 80% within the method determination ranges. However, this method is not suitable for the 10 remaining ICH classes 2 and 3 solvents, because they are too polar (e.g. formic acid and acidic acid), or have boiling points higher than 150 degrees C, (e.g. anisol and cumene). In comparison with the previous published methods, this method has a much shorter sample equilibration time, a better separation for many solvents, a higher sensitivity and a broader concentration range. PMID: 20801455 [PubMed - as supplied by publisher]
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Related Articles Influence of patient race on physician prescribing decisions: a randomized on-line experiment. J Gen Intern Med. 2009 Nov;24(11):1183-91 Authors: Rathore SS, Ketcham JD, Alexander GC, Epstein AJ BACKGROUND: Prior research reports black patients have lower medication use for hypercholesterolemia, hypertension, and diabetes. OBJECTIVE: To assess whether patient race influences physicians’ prescribing. DESIGN: Web-based survey including three clinical vignettes (hypercholesterolemia, hypertension, diabetes), with patient race (black, white) randomized across vignettes. SUBJECTS: A total of 716 respondents from 5,141 eligible sampled primary care physicians (14% response rate). INTERVENTIONS: None MEASUREMENTS: Medication recommendation (any medication vs none, on-patent branded vs generic, and therapeutic class) and physicians’ treatment adherence forecast (10-point Likert scale, 1-definitely not adhere, 10-definitely adhere). RESULTS: Respondents randomized to view black patients (n = 371) and white patients (n = 345) recommend any medications at comparable rates for hypercholesterolemia (100.0% white vs 99.5% black, P = 0.50), hypertension (99.7% white vs 99.5% black, P = 1.00), and diabetes (99.7% white vs 99.7% black, P = 1.00). Patient race influenced medication class chosen in the hypertension vignette; respondents randomized to view black patients recommended calcium channel blockers more often (20.8% black vs 3.2% white) and angiotensin-converting enzyme inhibitors less often (47.4% black vs 62.6% white) (P < 0.001). Patient race did not influence medication class for hypercholesterolemia or diabetes. Respondents randomized to view black patients reported lower forecasted patient adherence for hypertension (P < 0.001, mean: 7.3 black vs 7.7 white) and diabetes (P = 0.05 mean: 7.4 black vs 7.6 white), but race had no meaningful influence on forecasted adherence for hypercholesterolemia (P = 0.15, mean: 7.2 black vs 7.3 white). CONCLUSION: Racial differences in outpatient prescribing patterns for hypertension, hypercholesterolemia, and diabetes are likely attributable to factors other than prescribing decisions based on patient race. PMID: 19705205 [PubMed - indexed for MEDLINE]
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