Simultaneous High Performance Liquid Chromatographic Determination of Theophylline and Ethylenediamine in Aminophylline Dosage Forms as Their Dansyl Derivatives

Abstract

A simple HPLC method has been developed for the assay of the components of aminophylline (theophylline: ethylenediamine 2:1) in solid and liquid dosage forms. Following the extraction of tablets into or the dilution of a liquid dosage form with water, the aqueous extract was reacted with dansyl chloride in an alkaline medium. The mixture of the dansyl derivatives of theophylline and ethylediamine was analyzed on an reversed phase μBondapak Cia column, using a methanol-water-acetic acid-triethylamine (60–65: 33–38: 1. 5:0. 5) mobile phase delivered at the rate of 1.5 mL/min, and a detection wavelength of 254 nm. In addition to exhibiting excellent accuracy and precision, the method yielded detector responses that were linearly related to concentrations of theophylline and ethylenediamine in aminophylline of up to 7 mg of theophylline, and of up to 10 mg     

A New Simplified Microassay for the Quantitation of Theophylline in Serum by High-Performance Liquid Chromatography

Abstract

An improved, rapid and simplified HPLC method is presented for the quantitation of theophylline in serum. The internal standard, beta-hydroxypropyl theophylline (20 ul of a 100 ug/ml solution) is added to 50 ul of serum. Serum proteins are precipitated by the addition of 30 ul of 20% trichloroacetic acid solution. The mobile phase consists of a sodium acetate buffer with 8% acetonitrile. Chromatogram run time is 8 minutes. The sensitivity limit is 0.10 ug/ml. This method is interference free from the major metabolites of theophylline and other drugs commonly coadministered with theophylline.     

High-Performance Liquid Chromatographic Analysis of Theophylline in the Presence of Caffeine in Blood Serum and Pharmaceutical Formulations

Abstract

A reversed phase high-performance liquid chromatographic (HPLC) method has been established for the separation and quantitative determination of the alkaloid theophylline in the presence of caffeine -internal standard- in blood serum and in pharmaceutical preparations. The separation was performed on Spherisorb-5 RP-18 5μm reversed phase column using methanol: 0.038 M ammonium acetate: acetonitrile (38: 57:5) at a pH of about 7.20. The eluted alkaloids are detected at 272 nm. The retention time is 3.09 min for theophylline and 3.85 min for caffeine. The correlation of the integrated peak area with the concentration of theophylline showed a linear relationship between 0.05 to 5.0 theophylline in blood serum, tablets, sprinkels, syrups, suppositories and injectable solutions.     

Comparison of a RP-HPLC Method with the Therapeutic Drug Monitoring System TDx for the Determination of Theophylline in Blood Serum

Abstract

Blood serum samples of patients undergoing theophylline therapy were analysed in parallel with a new RP-HPLC method and the therapeutic drug monitoring TDx system. Both techniques are accurate, precise, technically easy, rapid, but the results taken by the TDx method are in all cases higher than HPLC. The mean increase is of about 56%.     

A Weak Cation-Exchange Monolithic SPE Column for Extraction and Analysis of Caffeine and Theophylline in Human Urine

A weak cation-exchange monolithic column has been prepared in stainless steel tubing and used as the solid-phase extraction material in quantitative analysis of caffeine and theophylline in urine. Column switching, with water as mobile phase, was used for on-line cleaning and screening of human urine samples. Reversed-phase high-performance liquid chromatography was then performed on a C₁₈ column with methanol–water 30:70 (v/v) as mobile phase at a flow rate of 0.5 mL min⁻¹. Ultraviolet detection was performed at 274 nm. Good linear relationships were obtained between response and concentrations of caffeine and theophylline in the range 0.1–50 μg mL⁻¹. Absolute recovery ranged from 77.4 to 82.3% and inter-day and intra-day relative standard deviations were less than 5%. The method was suitable for analysis of caffeine and theophylline in human urine, because it eliminated tedious pretreatment and enabled rapid, economic, repeatable, and effective assay of traces of the drugs in biological samples.

     

A Bidimensional HPLC System for Direct Determination of Theophylline in Serum

Abstract

A bidimensional HPLC system combining steric gel exclusion and reverse phase ODS columns for determination of theophylline in serum is reported. Factors involved in the development of the method and its performance are discussed. This technique is a practical alternative for the determination of theophylline levels in serum without any clean up procedure before chromatography.     

Improved High-Performance Liquid Chromatographic (HPLC) Assay Method for Ceftizoxime

Abstract

We improved a high-performance liquid chromatographic method for the quantitative determination of ceftizoxime in human serum and urine using cefotaxime as internal standard. It employs a μ Bondapak Alkyl Phenyl column, elution with acetonitrile-phosphate buffer and measurement of UV absorption at 254 nm. Results obtained using the HPLC assay were compared to those obtained using a microbiological assay. The correlation coefficient was 0.987 (n:25). The method is rapid, accurate and reproducible with a sensitivity of 2.5 μg/ml of ceftizoxime. Cefotaxime and its major metabolite, the desacetylcefotaxime, can also be quantitated by this procedure.     

The Analysis of Theophylline By HPLC

Abstract

Theophylline is a drug used in the treatment of asthma. Its therapeutic value is dependent upon its concentration in the blood with levels greater than 20 mg/1 causing side affects, sometimes severe. Various people metabolize the drug at different rates, so a method for analyzing serum Theophylline is necessary. We have developed a rapid, quantitative HPLC method for the analysis of serum Theophylline. No pretreatment of the sample is necessary, the method uses direct injection of the serum sample onto a guard column.     

Determination of Rubidium in Biological Materials by Atomic Absorption Spectrophotometry

Abstract

A sensitive and rapid quantitative method employing atomic absorption spectrophotometry was developed for the determination of low concentrations of Rb⁺ in urine, plasma and tissue. The method requires only a single set of Rb⁺ standards, which are applicable for samples containing variable amounts of Na and K. The sensitivity of detection is 0.001 meq/L of Rb⁺.     

Immunoassay for Highly Water-Soluble Nitenpyram: Evaluating the Analytical Performance of an Easy-to-Use Screening Method for Agricultural Samples

Abstract

Nitenpyram, a neonicotinoid insecticide, is highly soluble in water (>5.9?×?10⁵?mg/L). Specifically examining its physicochemical properties, we have established a simple and rapid residue analytical method for nitenpyram using an enzyme-linked immunosorbent assay (ELISA) which requires no organic solvents. The I₅₀ value found with this ELISA method using a selective monoclonal antibody toward nitenpyram was 4.8?ng/mL. A hand-shaking method using water was applied for ELISA analysis to extract nitenpyram from fruiting vegetable samples of four kinds. Matrix effects caused by interfering substances coexisting in aqueous sample extracts were reduced by dilution with water. No problems were found in the analytical values obtained using ELISA. From analyses of nitenpyram-incurred fruiting vegetables with the proposed ELISA and the reference HPLC protocols, high mutual correlation was found, which suggests that the measurement accuracy of the proposed ELISA method is comparable to the reference HPLC procedure.     

A High-Performance Liquid Chromatographic Method for the Determination of Doxefazepam in Human Plasma Using a Solid-Phase Extraction Column

Abstract

A procedure for the rapid, quantitative isolation of doxefazepam from plasma with Supelclean LC-18 cartridges is described together with a sensitive HPLC assay for the quantitative determination of the drug. The recovery of doxefazepam was greater than 80 % over an investigated range of 0.1–2.0 μg/ml of plasma. The column extraction of doxefazepam coupled with the versatility of HPLC make this procedure well suited for detailed pharmacokinetic studies and as well as routine plasma analysis of doxefazepam.     

31P NMR and HPLC Investigations of the Cyclophosphamide Metabolite,Phosphoramide Mustard

Abstract

Phosphoramide mustard (PM), a key active metabolite of the widely used anticancer drug cyclophosphamide (CP), can exist in several closely-related ionized, cyclized and substituted forms. We have developed a high pressure liquid chromatographic (HPLC) method for analysing serum concentrations of PM in order to relate these serum concentrations to toxicity and efficacy of treatment of CP. ³¹p NMR spectroscopy is used to verify the HPLC peak homology of the proposed PM peak.     

HPLC Separation of Tautomeric Compounds of 4-Aminoisoxazolyl-1,2-naphthoquinones. II

Abstract

HPLC separations and quantitative analysis are described for a mixture of 4-aminoisoxazolyl-1,2-naph-thoquinone isomers. This assay is simple, rapid and stability indicating because the precursors and isomerization products can be monitored simultaneously. The results obtained are in agreement with those obtained by UV spectroscopy.     

Rapid High Performance Liquid Chromatographic Determination of Ampicillin in Human Urine

Abstract

A rapid, sensitive and specific HPLC assay for the determination of ampicillin in human urine is developed.

Ampicillin was directly measured in human urine at 225 nm using a reversed phase column (Synchropack RP-P) and a mobile phase composed of (1:9 methanol-sodium acetate solution, 0.01 M, pH 4). The analysis required no longer than 10 min. Linear correlation between the peak height ratio of ampicillin to cefoxitin sodium (internal standard) and ampicillin concentration in urine over the range 10–100 μg ml^?1 was obtained. The developed method proved to be advantageous as it monitors ampicillin level in urine. Moreover, the urinary excretion of ampicillin in human subjects after an oral administration of 500 mg ampicillin capsules was established using the proposed method.     

High Performance Liquid Chromatographic Analysis of Cepoperazone in Serum and Urine

Abstract

A high performance liquid chromatographic method was developed for the quantitative analysis of cefoperazone in serum and urine. Standard curves were linear over the range of concentrations 2–30 μg/ml and a good correlation was established between the amount of cefoperazone injected and peak height. The mean percentage analytical recovery of cefoperazone was 96.3% and the mean within day coefficient of variation in serum was 2.8%. Serum and urine components, as well as several beta-lactam antibiotics, did not interfere with the measurement of cefoperazone. This is a rapid, reproducible, and sensitive assay suitable for use in pharmacokinetic studies.     

Simultaneous quantitative estimation of oxybenzone and 2-ethylhexyl-4-methoxycinnamate in sunscreen formulations by second order derivative spectrophotometry

Simultaneous determination of 2-ethylhexyl-4-methoxycinnamate (OMC) and oxybenzone (OB) in commercial sunscreen formulations has been achieved by using second order derivative spectrophotometry. The analytical methodology described does not require elaborate pretreatment of samples. The results obtained could be validated by reverse phase HPLC assay by using isocratic methanol: water (88: 12) solvent system. The sensitivity of the developed derivative spectrophotometry method was determined to be 9.0 × 10⁻³ L/mg for OB and 9.56 × 10⁻³ L/mg for OMC. The limit of instrumental detection (LOD) was determined to be 0.6 mg/L for OB and 1.38 mg/L for OMC with relative standard deviation of 0.001 and 0.004 for OB and OMC respectively. The method developed can be used for quick assay of commercial sunscreens. The article is published in the original.     

Detection and Quantitation of Bryostatin 1 and 2 in Bugula Neritina by Combined High-Peformance Liquid Chromatography and 3H-Phorbol Dibutyrate Displacement

Abstract

An HPLC method has been developed to detect and quantitate bryostatins 1 and 2 from crude extracts of B. neritina. This, coupled with a ³H-phorbol dibutyrate binding assay and photodiode array-acquired uv spectra makes possible the evaluation of crude extracts in a rapid, sensitive and specific manner.     

A Radioimmunoassay for Serum and Urine Aldosterone by Celite Column Chromatography

Abstract

A relatively simple and rapid radioimmunoassay (RIA) for the measurement of aldosterone in serum and urine has been developed. The method involves extraction of 1 ml of serum or urine (after acid hydrolysis) with dichloromethane, followed by partition chromatography on celite microcolumns prior to RIA. Dextran coated charcoal is used for separation of free from antibody-bound aldosterone. The method is very sensitive, blanks are negligible and recovery is approximately The%. 80 coefficient of variation is 4. 3% (within assay) and 10. 4% (between assay). When known amounts of aldosterone were added to serum and urine pools containing low endogenous levels of this steroid recovery was quantitative. Aldosterone concentrations measured under various physiological conditions were in agreement with published data. Up to 150 samples can be assayed by 1 technician during 5 working days.     

An HPLC Method for the Determination of Theophylline and Its Metabolites in Serum and Urine

Abstract

A urine and a serum assay have been developed to quantitate theophylline and its major metabolites:1,3-dimethyluric acid, 3-methylxanthine and 1-methyluric acid. Reverse phase chromatography follows a serum acetone extraction procedure and a urine anion exchange clean-up procedure. Lower limits of sensitivity are 0.04 μg/ml for serum metabolites and 1 μg/ml for urine metabolites. Both assays are free of interference from endogenous substances. These assays have been tested successfully in pharmacokinetic and metabolic studies of theophylline.     

A clinical trial for therapeutic drug monitoring using microchip-based fluorescence polarization immunoassay

Microchip analysis is a promising method for therapeutic drug monitoring. This led us to evaluate a microchip-based fluorescence polarization immunoassay (FPIA) system for point-of-care testing on patients being treated with theophylline. The sera were collected from 20 patients being treated with theophylline. Fluorescence polarization was measured on the microchip and theophylline concentrations in serum were obtained. Regression analysis of the correlations was done between the results given by the microchip-based FPIA and the conventional cloned enzyme donor immunoassay (CEDIA), and between the results given by the microchip-based FPIA and the conventional particle-enhanced turbidimetric inhibition immunoassay (PETINIA). We successfully carried out a quantitative analysis of theophylline in serum at values near its therapeutic range in 65 s. The results obtained by the microchip-based FPIA correlated well with CEDIA and PETINIA results; the correlation coefficients (R ²) were 0.986 and 0.989, respectively. The FPIA system is a simple and rapid method for point-of-care testing of drugs in serum, and its accuracy is the same as the conventional CEDIA and PETINIA. It is essential to use real samples from patients and to confirm good correlations with conventional methods for a study on the realization of microchip.