Sensitive and selective LC-MS/MS assay for quantitation of flutrimazole in human plasma.

OBJECTIVE: A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of flutrimazole in human plasma. This study was to investigate the application of sensitive and selective LC-MS/MS method for quantitation of flutrimazole in human plasma. MATERIALS AND METHODS: The analysis and internal standard were extracted with ether and hexane (v:v, 1:1) followed by a rapid isocratic elution with a 0.1% formic acid/methanol (v:v, 20:80) on a C18 column (50 mm × 2.1 mm I.D.) and subsequent analysis by mass spectrometry in the multi-reaction-monitoring mode. The precursor to production transitions of m/z 279.0 → 183.1 and m/z 441.0 → 295.1 were used to measure the analyte and the internal standard. RESULTS: The assay was linear over the concentration range of 0.996-99.6 ng•mL-1 for flutrimazole in human plasma. The lower limit of quantification was 0.996 ng•mL-1 and the extraction recovery was larger than 78.83% for flutrimazole. The inter- and intra-day precision of the method at three concentrations was less than 9.26%. CONCLUSIONS: The LC-MS/MS method was firstly applied to quantitation of flutrimazole in human plasma.

[Risk factors of hypoparathyroidism following total or near total thyroidectomy].

OBJECTIVE: To study the risk factors for postoperative hypoparathyroidism or hypocalcemia. METHODS: Totally 414 patients with thyroid diseases who underwent total or near total thyroidectomy at Department of Head and Neck Surgery, Peking University Cancer Hospital and Institute from June 2007 to June 2014 were studied retrospectively. There were 119 male and 295 female patients with a median age of 47 years. The clinical and pathological features that related to post-operative hypoparathyroidism were studied by χ(2) test and multivariate Logistic regression analysis. RESULTS: Of the 414 patients, 36.2% developed transient hypocalcemia, 36.5% developed transient hypoparathyroidism, 2.2% developed permanent hypoparathyroidism. In regression analysis, unilateral or bilateral center lymph node dissection were associated with mild transient hypocalcemia after surgery (OR=2.366, P=0.022; OR=5.216, P=0.000); unilateral or bilateral center lymph node dissection as well as surgical options were significant risk factors for severe transient hypocalcemia (OR=4.029, P=0.001; OR=8.384, P=0.000; OR=2.073, P=0.017) and hypoparathyroidism (OR=1.755, P=0.040; OR=4.144, P=0.000; OR=2.287, P=0.000). The parathyroid hormone concentration on postoperative day 1 was an independent risk factor for permanent hypoparathyroidism (OR=2.011, P=0.014). The concentration of parathyroid hormone threshold <5.28 ng/L was a predictor to permanent hypoparathyroidism with accuracy of 95.0%. CONCLUSIONS: Bilateral center lymph node dissection is a risk factor of permanent hypoparathyroidism in patients received total thyroidectomy should be taken thoughtfully. The parathyroid hormone concentration on postoperative day 1 provides better prediction for persistent hypoparathyroidism.