Stability of standard curves prepared for EMIT homogeneous enzyme immunoassay kits stored at room temperature after reconstitution.
(9/13)
We examined the stability of standard curves obtained with use of homogeneous enzyme immunoassay reagents (EMIT; Syva Corp., Palo Alto, CA) for assay of lidocaine, procainamide, N-acetylprocainamide, gentamicin, and theophylline, when stored at room temperature (23-24 degrees C) after reconstitution of the lyophilized materials. Standards were run and curves obtained for as long as 16 days after reconstitution. All standard curves were acceptable, according to the criteria specified in Syva product literature. Absorbance changes for all calibrators, including the zero calibrator, increased gradually with time. Increases of non-zero calibrators were largely offset by a parallel increase in the zero calibrator, such that the quantity delta A--delta A0 was very nearly constant with time. Standard curves based on the quantity delta A--delta A0 can be used for longer than curves based only on delta A. (+info)
Simultaneous quantitation of quinidine, procainamide, and N-acetylprocainamide in serum by gas-liquid chromatography with a nitrogen-phosphorus selective detector.
(10/13)
We describe a single-run method for quantitating quinidine, procainamide, and N-acetylprocainamide, involving gas-liquid chromatography with a nitrogen-phosphorus selective detector. Within-run precision (CV) was 3% (x = 2 mg/L, n = 20), 6.9% (x = 4 mg/L, n = 10), and 1.5% (x = 8 mg/L, n = 8) for quinidine; 7.7% (x = 4 mg/L, n = 14), 1.6% (x = 8 mg/L, n = 16), and 2.3% (x = 12 mg/L, n = 12) for procainamide; and 6.3% (x = 5 mg/L, n = 6), 3.6% (x = 10 mg/L, n = 20), and 4.0% (x = 20 mg/L, n = 10) for N-acetylprocainamide.l Between-run precision was 3.0%(x = 2 mg/L, n = 20), 7.0% (x = 4 mg/L, n = 9), and 2.8% (x = 8 mg/L, n = 9) for quinidine; 4.7% (x = 4 mg/L, n = 10). 3.3% (x = 8 mg/L, n = 20), and 1.9% (x = 12 mg/L, n = 10) for procainamide; and 9.3% (x = 5 mg/L, n = 6), 4.3% (x = 10 mg/L, n = 20), and 3.8% (x = 20 mg/L, n = 10) for N-acetylprocainamide. Tube stoppers that contain a rubber plasticizer interfere with the technique. Clinical application and correlation with drug concentrations by this technique are discussed. (+info)
Theophylline, dyphylline, caffeine, acetaminophen, salicylate, acetylsalicylate, procainamide, and N-acetylprocainamide determined in serum with a single liquid-chromatographic assay.
(11/13)
We describe a single set of liquid-chromatographic conditions for assay of theophylline, dyphylline, caffeine, acetaminophen, salicylate, acetylsalicylate, procainamide, and N-acetylprocainamide in serum. The chromatographic system includes a Waters Associates mu-Bondapak C18 column and acetonitrile in 0.1 mol/L potassium phosphate buffer, pH 4.0 (9.75/90.25 by vol), as the mobile phase. Only 50 microL of serum is required, and drug concentrations as low as 0.5 mg/L can be detected. Absolute and relative analytical recoveries range from 95 to 101%. Day-to-day variation of the method is less than 6% for each drug. Linearity extends to 1 g/L for all drugs. Recycling of the mobile phase under pressure eliminates the need to prepare and de-gas solvents. The use of the single stationary and mobile phase provides a practical and economical approach to routine and urgent therapeutic drug monitoring. (+info)
Fluoroimmunoassays for procainamide and N-acetylprocainamide compared with a liquid-chromatographic method.
(12/13)
We measured procainamide and its active metabolite, N-acetylprocainamide (NAPA), in 80 sera from 37 patients by a new fluorimmunoassay procedure and an established "high-performance" liquid-chromatographic method. Additive and proportional differences between the methods were 0.07 mg/L and 9%, respectively, for procainamide and 0.62 mg/L and 16% for NAPA. Between-day CVs by the chromatographic and immunoassay methods, respectively, were 3.9% and 2.2% for procainamide at a concentration of 6 mg/L, and 5.1% and 1.2% for NAPA (14 mg/L). We applied a modification of the fluoroimmunoassay for determination of procainamide concentrations, using sera obtained during a pharmacokinetic study, and demonstrated excellent agreement with the chromatographic method. (+info)
Improved high-performance liquid chromatographic assay for the determination of procainamide and its N-acetylated metabolite in plasma: application to a single-dose pharmacokinetic study.
(13/13)
An improved high-performance liquid chromatographic assay for the determination of procainamide and N-acetylprocainamide (NAPA) at concentrations observed up to 32 h after a single oral dose administration of procainamide to human subjects is reported. Following liquid-liquid extraction of plasma samples, procainamide, NAPA, and the internal standard (N-propionylprocainamide) are separated on a reversed-phase C8 column with retention times of 4.0, 6.7, and 13.2 min, respectively. The ultraviolet detection limit (wavelength, 280 nm) of procainamide and NAPA is 2 ng/mL (signal-to-noise ratio, 3:1), and the quantitation limit is 4 ng/mL (signal-to-noise ratio, 5:1). Intra- and interday coefficients of variation are less than 8% in the range of 20-500 ng/mL. (+info)