Determination Of Theophylline Concentrations Research Articles

Quantification of Theophylline in Guinea Pig Plasma by LC-MS/MS Using Hydrophilic Interaction Liquid Chromatography Stationary Phase: Method Development, Validation, and Application in Study

AbstractTheophylline has been used in the treatment of bronchial asthma and chronic obstructive pulmonary disease (COPD) for over 70 years. In order to maximize the effectiveness and safety of theophylline therapy it is important to individualize the dosage of the drug. In our study we focused on determination of theophylline concentrations in guinea pig plasma. A rapid, specific, and reliable LC-MS/MS-based method was developed and validated according to European Medicine Agency (EMA) guidelines. A hydrophilic interaction liquid chromatography (HILIC) separation mode for reduction time of sample preparation was used. The analysed sample was quantified in a positive ionization mode. Multiple reaction monitoring (MRM) using transition m/z 181.06→124.06 and m/z 187.17→127.06 was performed to quantify theophylline with deuterated internal standard ([2H6]-theophylline), respectively. Modification of collision energies was performed in parallel with chromatographic separation to further eliminate interference from the matrix. The method was validated for a range of 0.5 to 30 μg/mL of plasma sample. The intra-day and inter-day precision and accuracy of the quality control samples at low, me dium, and high concentration levels exhibited relative standard deviations (RSD) of less than 10 %. The method was successfully applied for the quantitation of theophylline in guinea pig plasma for better understanding its effects in a model of ovalbumin-induced allergic inflammation.

Determination of theophylline concentration in serum by chemiluminescent immunoassay

This study aimed to establish chemiluminescent immunoassay (CLIA) for quantitative determination of theophylline levels in human serum. To measure the concentration of theophylline (n=122) and evaluate the assay. The linear range of the CLIA method was 0.51-40 mg/L (Y=1.02X+0.44, r=0.995). The intra and inter CV (coefficient variance) of CLIA were 3.20% and 3.57%, respectively. The average recovery rate was 102.3%. This method was free from interference by brilirubin (<200 micromol/L), hemoglobin (<10 g/L), and triglycerides (<15 mmol/L). This method is simple, convenient and precise for clinical pharmacokinetics study of theophylline.

Detection of small organic analytes by fluorescing molecular switches

A sensor system was developed for the determination of theophylline concentrations based on a theophylline-dependent allosteric ribozyme (Soukup, G. A.; Breaker, R. R. Proc. Natl. Acad. Sci. U.S.A. 1999, 96, 3584) in combination with an RNA substrate which is double-labeled with a fluorophore and a quencher dye. In the presence of theophylline, a hammerhead ribozyme domain is switched into an active conformation by the action of a theophylline-binding aptamer domain. Upon substrate cleavage, the quencher is removed from the vicinity of the fluorophore, causing an increased fluorescence signal. Real-time analysis of the cleavage reactions both under single and multiple turnover conditions revealed a dependence on the cleavage rate within a range from 0.01 to 2 mM theophylline. The structurally similar molecule caffeine, however, had no detectable influence on the fluorescence signal.

An HPLC Method for the Determination of Theophylline Concentrations in Plasma from Both Healthy Rats and in Rats with Carbon Tetrachloride Induced Cirrhosis

Abstract An accurate and reproducible high performance liquid chromatographic assay for theophylline in rat plasma has been developed. After addition of ammonium sulfate to the samples, theophylline is extracted from the plasma into chloroform. Beta-hydroxyethyl theophylline is used as the internal standard and separation is achieved using a Zorbax ODS (C18) column with a gradient mobile phase system, consisting of 0.05 M sodium acetate and acetonitrile. Samples are quantitated by UV detection of the column effluent at 275 nm. The assay can accurately and precisely measure theophyliine concentrations in rat plasma ranging from 0.25 to 7.5 μ/ml. This procedure has been successfully applied to the analysis of rat plasma samples obtained from both healthy rats and rats with carbon tetrachloride induced cirrhosis.

Plasma theophylline concentration and lung function in ponies with recurrent obstructive lung disease

Six ponies with recurrent obstructive lung disease were studied during two separate 60 min periods while receiving constant equal volume infusions of either aminophylline or sterile water. Dynamic lung compliance, pulmonary resistance, respiratory rate, tidal volume, blood gas tensions and heart rate were measured. Plasma samples were obtained for determination of theophylline concentrations before, and at 10 min intervals during, the infusion period. Excitability was assessed subjectively at these same time periods. The plasma theophylline concentrations in ponies were well predicted by a previously published model of theophylline pharmacokinetics in the horse. Sterile water had no effect on lung function. Aminophylline produced significant changes in lung function compared to baseline values, including a decrease in resistance at 30 min when the mean plasma theophylline concentration was 59 +/- 14 mumol/litre and an increase in compliance at 60 mins at a mean plasma theophylline concentration of 102 +/- 23 mumol/litre. Excitement was noted between 40 and 50 mins in all ponies (mean plasma theophylline concentration 74 +/- 20 and 84 +/- 24 mumol/litre, respectively). Heart rate increased at 50 mins. The therapeutic range for intravenous (iv) theophylline concentration in 'heavey' ponies therefore appears to be between 59 and 84 mumol/litre when aminophylline is administered iv. Below 59 mumol/litre there was no consistent bronchodilator activity and above 84 mumol/litre excitement and tachycardia limited the usefulness of the drug.

The influence of intravenous cimetidine dosage regimens on the disposition of theophylline.

The influence of the method of cimetidine administration on theophylline disposition was studied in nine healthy, cigarette smoking male volunteers. The treatment phases consisted of: A) theophylline alone, B) theophylline plus intermittent cimetidine therapy (300 mg IV every 6 hr), and C) theophylline in combination with continuous infusion cimetidine (50 mg/hr). Theophylline (4.8 mg/kg) was administered intravenously as aminophylline over 30 minutes during each treatment phase. During study phases B and C subjects received 48 hours of cimetidine therapy beginning 24 hours prior to theophylline dosing. Blood samples for determination of theophylline concentrations were collected serially over 24 hours. Serum theophylline concentrations were determined in duplicate using fluorescence polarization immunoassay (Abbott Diagnostic TDx). The average age of the subjects was 27.4 +/- 4.7 years, and the individual smoking histories ranged from 0.5 to 1.5 packs per day (average 0.89 +/- 0.33). The mean (+/- SD) body weight was 79.1 +/- 8.2 kg and all subjects were within 20% of their ideal body weight. Theophylline pharmacokinetic parameters were determined using noncompartmental analysis. ANOVA for repeated measures and Tukey's multiple comparison test were used for statistical analysis. The mean (+/- SD) theophylline clearance for each of the treatment groups was: 1.4 +/- 0.4, 1.2 +/- 0.3, and 1.2 +/- 0.2 ml/min/kg for phases A, B and C, respectively. Cimetidine decreased the clearance of theophylline, however, theophylline clearance was not statistically different between regimens B and C. Thus, the method of cimetidine administration (intermittent versus continuous infusion) did not influence the magnitude of the drug-drug interaction.

Liquid chromatographic determination of theophylline concentration with syringe-type minicolumns for direct plasma injection.

Liquid chromatographic determination of theophylline concentration with syringe-type minicolumns for direct plasma injection.

Comparison of the Seralyzer and EMIT systems for determination of theophylline concentrations

A reflectance photometry assay for measurement of serum theophylline concentration was evaluated by comparison with an enzyme-multiplied immunoassay technique (EMIT). The concentration of theophylline in blood samples obtained from patients receiving intravenous theophylline therapy in the pediatric intensive-care unit was measured by both the Seralyzer and the EMIT systems. The interday and intraday variability of each method were also determined by means of calibrators of known concentration (5 to 40 micrograms/mL). There was significant correlation between the serum theophylline concentrations determined by the Seralyzer system and the EMIT system. The overall standard error of the estimate was 2.3 micrograms/mL, but with operator experience this improved to 1.3 micrograms/mL. Intraday variability was 1.2 micrograms/mL for the Seralyzer and 0.7 micrograms/mL for EMIT; the respective values for interday variability were 1.4 micrograms/mL and 0.8 micrograms/mL. The Seralyzer method measures theophylline concentrations with reliability, convenience, and speed. It could be potentially useful in a satellite, clinic, or acute-care pharmacy area.

The validation of a fluoroimmunoassay for the determination of theophylline concentration in dried blood spots suitable for domiciliary therapeutic drug monitoring

A commercially available substrate-labelled fluorescent immunoassay procedure has been modified to create a simple rapid method for the determination of capillary theophylline concentration in the dried filter paper blood spots of patients on theophylline therapy. The specimens are collected and dispatched to the laboratory by the patient; thus domiciliary monitoring of theophylline therapy can take place. The technique offers a convenient method for overcoming many of the practical problems that arise during theophylline therapy in asthmatic patients.

An Evaluation of Syva System (AC-5000) by Application of Homogeneous Enzyme Immunoassay for Determination of Theophylline Concentration in Body Fluid

The applicability of recently developed instrument, automatic Syva System AC-5000 (EMIT-AC), was evaluated. The concentration of total or free theophylline (TH) in plasma, serum, saliva, and spiked sample was measured by EMIT-AC. The results were compared with those obtained by high performance liquid chromatography (HPLC) or substratelabeled fluorescent immunoassay (SLFIA). There was no significant difference (P>0.05) between the results obtained by EMIT-AC and HPLC method using TH spiked samples. The within-day precision of EMIT-AC method was less than 4.5% as the coefficient of variation (C.V.). The C. V. value for between-day precision was 6.3% for EMIT-AC and 3.7% for HPLC method and no significant difference (P>0.05) was observed between the mean values. A good correlation was obtained between EMIT-AC and HPLC method (n=54, r=0.988, P<0.001 for plasma; n= 22, r= 0.998, P<0.001 for serum) in the assay of total TH level. Similar observation was obtained in the free level assay. It was clarified that saliva level can also be analyzed by EMIT-AC method as well as SLFIA method. These findings show that EMIT-AC method is a satisfactory analytical device for giving correct results and applicable for the determination of TH level in body fluid especially in clinical drug monitoring requiring rapidity.

Determination of Salivary Theophylline Concentration by SLFIA Method and Pharmacokinetics in Saliva

Recently, we have reported that theophylline concentrations in plasma as determined by substratelabeled fluorescent immunoassay (SLFIA) well correlated (r= 0.96) with the concentrations by high-pressure liquid chromatography, and that SLFIA procedure had considerable advantages over hitherto available method. Methods for measurin.g theophylline in saliva previously reported were spectrophotometry, gas-liquid and high-pressure liquid chromatographies. Here, we used the SLFIA for the determination of theophylline concentrations in saliva. It was possible to determine salivary theophylline in low concentrations by using salivary altered first dilution rates with SLFIA method. The concentrations of theophylline in the plasma and saliva in 7 normal adults and 3 asthmatic patients who were administered aminophylline were determined by SLFIA method. In normal adults, the time-course of plasma and salivary theophylline levels showed a parallel relationship, and theophylline concentrations in the saliva as determined 2 and 4 hours after administration were about 44% lower than those in the plasma. In asthmatic patients, theophylline concentrations in saliva 2, 4, 6 and 8 hours after administration were also 32% lower than those in the plasma. These results suggested that monitoring patients by means of salivary theophylline level is effective way to predict plasma levels and to help patients avoid pain of bloodletting.

Comparison of Radioimmunoassay with Homogeneous Enzyme Immunoassay for the Determination of Theophylline Concentration in Serum

The homogeneous enzyme immunoassay (EMIT) and radioimmunoassay (RIA) procedures for the quantitation of theophylline concentrations in serum were evaluated and compared. Both methods exhibited curves linear over the therapeutic range (range of concentration, 2.0-33.0 microgram/ml). Precision was acceptable for both methods with the coefficient of variation being less than 8.3%. The RIA procedure was found to be slightly more precise. The correlations between the EMIT and RIA procedures was found to be sufficient to allow the procedures to be used interchangeably. This would facilitate the test availability on a 24 hr, 7 day basis.

Comparison of homogeneous enzyme immunoassay and high-pressure liquid chromatography for the determination of theophylline concentration in serum.

A comparison of the new homogeneous enzyme-multiplied immunoassay technique (EMIT, Syva) with a high-pressure liquid chromatographic technique for the determination of theophylline concentration is presented. The accuracy, precision, and specificity of the methods were compared. In addition, 100 samples from 61 pediatric patients receiving theophylline were assayed by both methods. The accuracy, precision, and specificity of the enzyme immunoassay support the use of this method for the quantification of theophylline concentration in clinical specimens. A significant correlation (R = 0.981, P less than 0.001) was found between results generated by enzyme immunoassay and high-pressure liquid chromatography for patient samples. The regression line relating these results had an intercept of 0.22 microgram per ml, a slope of 1.05, and a standard error of the estimate of 1.36 microgram per ml.

Indirect Plasma-Theophylline Monitoring in Asthmatic Children by Determination of Theophylline Concentration in Saliva

The concentration of theophylline in mixed saliva and in plasma of 16 asthmatic children on regular theophylline therapy was obtained two and four hours after a maintenance dose. There is a strong and highly statistically significant correlation between the theophylline concentration in saliva and plasma. This correlation is not affected by the pH or flow rate of saliva. The concentration of theophylline in plasma could be predicted from the concentration in saliva within ± 10% in 20, and within ± 20% in all of the 32 samples. Determination of theophylline concentrations in saliva is an effective, convenient, noninvasive, and painless method for routine indirect monitoring of plasma-theophylline concentrations in asthmatic children on regular theophylline therapy.