Determination of nifedipine in serum or plasma by reversed-phase liquid chromatography.

1983 ◽  
Vol 29 (7) ◽  
pp. 1344-1348 ◽  
Author(s):  
P R Bach

Abstract Therapeutic concentrations of nifedipine in serum or plasma were measured by reversed-phase liquid chromatography, with detection by ultraviolet absorbance at 235 nm. In the procedure a disposable reversed-phase extraction column is used. A 1-mL sample is required. The method is sensitive to 3 micrograms of nifedipine per liter and the standard curve is linear to at least 400 micrograms/L. Coefficients of variation at 100 micrograms/L were 2.2% within-run, 2.8% between-run. The method has been used to determine nifedipine in patients involved in a test of its efficacy in treating muscular dystrophy.

2000 ◽  
Vol 83 (4) ◽  
pp. 830-836 ◽  
Author(s):  
Jun Suo Li ◽  
Xi Wang Li ◽  
Jian Xiang Yuan ◽  
Xin Wang

Abstract A procedure was developed for the preparation of anti-sulfonamide (SA) group-specific antibodies and immunosorbents. Sulfonamide haptens and conjugates were synthesized by building spacer arms on an N1 group of 4-aminobenzensulfonamide. The anti-SA group-specific antibodies and immunosorbents were prepared successfully. After extraction with methanol–water (8 + 2), sulfamonomethoxine, sulfadimethoxine, and sulfaquinoxaline were cleaned up on immunoaffinity columns and determined by reversed-phase liquid chromatography with UV detection at 270 nm. The recoveries from fortified swine meat (10–100 μg/kg) ranged from 70.8 to 94.1%, with coefficients of variation of 3.4–12.9%. Limits of detection were 1–2 μg/kg.


1983 ◽  
Vol 29 (7) ◽  
pp. 1431-1434 ◽  
Author(s):  
H J Nelis ◽  
J De Roose ◽  
H Vandenbavière ◽  
A P De Leenheer

Abstract A new assay for retinol in human serum, based on nonaqueous reversed-phase liquid chromatography, is presented. Sample preparation includes addition of the internal standard, retinyl propionate, deproteinization of 100 microL of serum with acetonitrile, and extraction with hexane. The standard curve is linear up to 2 mg/L. The assay is characterized by excellent sensitivity (detection limit, 15 micrograms/L) and good within-run and between-run precision (CVs of 2.6 and 2.7%, respectively), and results compare favorably with those by fluorimetry. We assayed 135 samples from hospitalized patients by both methods. Although the two sets of values correlated well (r = 0.955) the fluorimetric method occasionally suffers from interferences. In practice, fluorimetry proves valuable as a routine method, while liquid chromatography meets the criteria of a potential reference method.


1993 ◽  
Vol 76 (5) ◽  
pp. 956-961 ◽  
Author(s):  
Robert E Sapp ◽  
Sandra Davidson

Abstract A method is presented for detection and quantitation of Roxarsone in poultry feed by liquid chromatography. The drug is extracted by phosphate buffer and determined by solid phase extraction and reversed-phase liquid chromatography. Recoveries of the sample spikes and fortified field samples agree closely with those obtained by the standard spectrophotometric method.


1994 ◽  
Vol 77 (2) ◽  
pp. 331-333 ◽  
Author(s):  
Wayne Chan ◽  
Geoff C Gerhardt ◽  
Craig D C Salisbury

Abstract A method for the simultaneous determination of ty-losin and tilmicosin residues in animal tissues is reported. Solid-phase extraction columns are used to isolate the drugs from tissue extracts. Determination is accomplished by reversed-phase liquid chromatography with UV detection at 287 nm. Mean recoveries from spiked tissues were 79.9% (coefficient of variation [CV], 8.1%) for tylosin and 92.6% (CV, 8.7%) for tilmicosin. Detection limits for tylosin and tilmicosin were 0.020 and 0.010 ppm, respectively.


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