Capillary zone electrophoresis for the determination of atovaquone in serum

LC-APCI mass spectrometric method development and validation for the determination of atovaquone in human plasma

A newly developed LC-APCI mass spectrometric method is described for human plasma determination of atovaquone using lapachol internal standard. A single-step protein precipitation technique for plasma extraction of atovaquone achieving mean recovery of 94.17% (CV 8%) without compromising sensitivity (limit of quantitation 50.3 ng/mL) or linearity (50.3 ng/mL-23924.6 ng/mL) is delineated in this paper. Heated nebulizer in negative multiple reaction monitoring mode was employed with transitions m/z 365.2 --> m/z 337.1 and m/z 240.9 --> m/z 185.7 for atovaquone and lapachol respectively in this liquid chromatographic-tandem mass spectrometric method. Excellent chromatographic separation on a Synergi 4 micro Polar-RP 80A (150 x 2.0 mm) column, using 100 microL of plasma extraction volume along with 10 microL of injection load, completing analysis run-time within 2.5 min, highlights this simple yet unique bioanalytical method. The developed method can be successfully applied to pharmacokinetic studies on atovaquone suspension administered in healthy volunteers or HIV-infected patients. Moreover full method validation results not published before are presented and discussed in detail for the first time in this article.

Simultaneous determination of proline and pipemidic acid in human urine by capillary electrophoresis with electrochemiluminescence detection

Pipemidic acid is extensively used in the treatment of Gram-negative urinary tract infections, and the contents of proline in human urine vary in association with chronic uremia. The simultaneous determination of pipemidic acid and proline in human urine is of significance for quality control of the dosage and clinical study. The coupling of Ru(bpy)(3)(2+)-based electrochemiluminescence detection with capillary electrophoresis was developed for the simultaneous determination of proline and pipemidic acid in human urine. Parameters related to the separation and detection were investigated and optimized. The standard curves were linear between 0.1 and 90 µg mL(-1) for proline and between 0.4 and 100 µg mL(-1) for pipemidic acid. Underoptimized conditions, the detection limits (3σ) were 0.02 µg mL(-1) for proline and 0.06 µg mL(-1) for pipemidic acid. Relative standard derivations for the electrochemiluminescence intensity and the migration time were 3.2 and 0.9% for proline and 3.7 and 1.2% for pipemidic acid, respectively. The developed method was successfully applied to determine proline and pipemidic acid in human urine. The result showed that the content and decreasing rates of proline in urine for male were higher than that for female, and the content and decreasing rate of pipemidic acid in urine for male and female were consistent, respectively.

Separation and detection of vitellogenin in fish plasma by capillary zone electrophoresis

A method for coupling capillary zone electrophoresis (CZE) with rapid membrane chromatography purification (RMCP) was established for the analysis of vitellogenin (VTG) in male fish plasma induced with 17ss-estrodiol. CZE analyses of purified VTG were performed in a buffer containing 25 mM sodium borate (pH 8.4). A 50 microm i.d. fused-silica capillary was used for separation and the detection was carried out by UV-diode array at 214 nm. Inter- and intra-assay variabilities of the proposed method were less than 10.06 and 1.95%, respectively. The method has good linear relationship over the scope of 15-2250 microg/ml with a correlation coefficient of R2 = 0.9965 and a detection limit of 7.0 microg/ml. The established CZE method was also applied to directly separate and identify VTG from fish plasma. The results indicated this method could minimize interferences from plasma proteins, allowing the detection of at least 62.5 microg/ml of VTG proteins in total proteins. This is a rapid and easy method to determine the quantity and purity of VTG compared to Bradford method and SDS-PAGE.