Determination Of Theophylline Research Articles

Geographic origin classification and simultaneous determination of methylxanthines in vietnamese tea using chemometrics based on the near infrared reflectance spectroscopy

This paper reported the results of classification of geographic origin and simultaneous analysis of three methylxanthines (caffeine, theobromine, theophylline) in Vietnamese tea samples by the infrared reflectance spectrophotometry coupled with chemometrics. The spectral range was 10,000-4,000cm-1 and each spectrum was measured at 2 cm-1 intervals. For the purpose of geographic origin classification, this study used FT-NIR spectroscopy combined with Partial Least Squares Discriminant Analysis (PLS-DA), and Principal Component Analysis-Discriminant Analysis (PCA-DA). The ability to determine the origin of tea samples in the prediction set of PLS-DA model is 100%. Using the same IR spectral database combined with the partial least squares (PLS), three methylxanthines in tea samples are also quickly quantified. The PLS model based on the spectra of 24 tea samples in which the contents of 3 analytes were determined by high performance liquid chromatography- HPLC) were applied for simultaneous determination of caffeine, theobromine and theophylline in samples. The determination of methylxanthines in 7 tea samples in test set gave the good accuracy of the PLS model. The correlation coefficients (R2) in the prediction set were of 0.9582, 0.8894 and 0.9303 for theobromine, theophylline, and caffeine, respectively. This work demonstrated that infrared reflectance spectrophotometry combined with chemometrics could be applied to rapidly classify the geographic origin and simultaneous determination of main contents in green tea.

An Electrochemical Sensor of Theophylline on a Boron-Doped Diamond Electrode Modified with Nickel Nanoparticles.

Theophylline is a drug with a narrow therapeutic range. Electrochemical sensors are a potentially effective method for detecting theophylline concentration to prevent toxicity. In this work, a simple modification of a boron-doped diamond electrode using nickel nanoparticles was successfully performed for a theophylline electrochemical sensor. The modified electrode was characterized using a scanning electron microscope and X-ray photoelectron spectroscopy. Square wave voltammetry and cyclic voltammetry methods were used to study the electrochemical behavior of theophylline. The modified nickel nanoparticles on the boron-doped diamond electrode exhibited an electrochemically active surface area of 0.0081 cm2, which is larger than the unmodified boron-doped diamond's area of 0.0011 cm2. This modified electrode demonstrated a low limit of detection of 2.79 µM within the linear concentration range from 30 to 100 µM. Moreover, the modified boron-doped diamond electrode also showed selective properties against D-glucose, ammonium sulfate, and urea. In the real sample analysis using artificial urine, the boron-doped diamond electrode with nickel nanoparticle modifications achieved a %recovery of 105.10%, with a good precision of less than 5%. The results of this work indicate that the developed method using nickel nanoparticles on a boron-doped diamond electrode is promising for the determination of theophylline.

Highly sensitive and selective electrochemical sensor for simultaneous determination of gallic acid, theophylline and caffeine using poly(l-proline) decorated carbon nanotubes in biological and food samples

In this work, a novel, simple and reproducible poly(l-proline)/functionalized multi-walled carbon nanotube composite on glassy carbon electrode (poly(PRO)-MWCNTs/GCE) was developed as an electrochemical sensor for the simultaneous determination of gallic acid (GA), theophylline (TP) and caffeine (CAF) by differential pulse voltammetry (DPV).The sensing platform was optimized by experimental design and response surface methodology, using various factors affecting polymerization and detection, such as electropolymerization time and potential, and pH, respectively. As a result, the dispersion conditions were the mixing of 1.78 mg MWCNTs with 1.00 mL l-proline solution to 4.14 mg mL−1 (in SDBS 0.5%), followed by 21 min of sonication with electropolymerization by 16 cyclic scans. In addition, the final analysis was performed at a pH of 3.00 and prior accumulation at 0.350 V for 40 s.The electrochemical behavior of GA, TP and CAF on the optimized sensor was investigated. As a result, the electrode preserves and synergistically combines the properties of each modifier. This new electrochemical sensor showed superior electrocatalytic properties for the oxidation of GA, TP and CAF, which significantly improved the sensitivity of the three compounds.Under the optimized experimental conditions, the detection limits achieved by S/N were 0.03, 0.04 and 0.11 μmol L−1 for GA, TP and CAF, respectively. The analysis of real samples was successfully performed in human breast milk, tea, infusion of yerba mate, coffee, Coca-Cola zero and energy drink, showing good recoveries, ranged between 87 and 108%. The proposed sensor also showed good selectivity, repeatability and reproducibility, indicating feasibility and reliability.This is the first time that the l-proline monomer is used as a dispersant for MWCNTs and as a precursor for the in-situ polymerization of the proline polymer. Previously, the electropolymerizations were carried out with the monomer in solution rather than as an exfoliant of MWCNTs, where the polymer is electrosynthesized between MWCNTs rather than on them. In this way, the large specific surface area and strong adsorption ability of the nanomaterial are enhanced, and the ability to promote electron transfer reaction is increased, which provides enough effective reaction sites.

Electrochemical Sensing Platform Based on Carbon Dots for the Simultaneous Determination of Theophylline and Caffeine in Tea.

A simple and selective method for the determination of caffeine (CAF) and theophylline (THEO) has been developed for a glassy carbon electrode (GCE) modified with a composite including carbon dots (CDs) and chitosan (CS). To our knowledge, there are no previous studies that analyze a CDs-modified GCE for the presence of CAF and THEO. The electrochemical behavior of a GCE modified with a CDs-CS composite was studied in acidic medium by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Considering the sensor analytical parameters, the same linear concentrations range was found for CAF and THEO ranging from 1 × 10-5 to 5 × 10-3 mol L-1 with the same detection limit (LOD) of 1 × 10-6 mol L-1. The reproducibility and repeatability data were satisfactory in terms of RSD%. Moreover, the storage stability was evaluated, evidencing good results whatever the experimental conditions used. The developed sensor was applied for the simultaneous determination of CAF and THEO in tea and drug, and results were compared with those obtained with HPLC-ESI-MS in SIR mode as an independent method optimized on purpose. The electrochemical sensor presents the undoubled advantages in terms of cheapness, portability, and ease of use, since it does not require skilled personnel.

Size dependent catalytic activities of facile synthesized strontium zinc oxide for the electrooxidation of theophylline in food samples

In this work, we report an electrochemical determination of theophylline (THY) based on nanostructured strontium-zinc oxide (ns-ZSO). First the microstructure strontium-zinc oxide (ms-ZSO) prepared through coprecipitation method followed by calcination at high temperature to form ns-ZSO. Subsequently, the physicochemical properties of the resulting materials were investigated by various spectroscopic and microscopic techniques. Further, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrocatalytic properties of prepared catalysts. The optimized ns-ZSO catalyst showed an active surface area of 0.579 cm2, a significant increase in redox peak current were absorbed for ns-ZSO. The dependence of the peak potentials and currents on pH and scan rates was also inspected and the working parameters were optimized. This sensor exhibited a low detection limit of 0.54 ng/L, with a linear dynamic range from 3.60 to 108.09 ng/L and sensitivity of 15.72 μA/μM cm2. Moreover, the proposed sensor exhibits good stability, reproducibility, repeatability and selectivity. In addition, ns-ZSO modified electrode is applied to the determination of THY in-blood serum and-food samples with the acceptable recovery.

Detection of Theophylline using Samarium Oxide Nanoparticles Ingrained Graphite Electrode

In this overview, a significantly low-cost electrode for the quick determination of theophylline (THP) using graphite electrode ingrained with samarium oxide nanoparticles is fabricated. The electrochemical behavior of the fabricated electrode is studied in details using cyclic and differential pulse voltammetry (DPV). The electrode has shown a linear working range of 10–1000[Formula: see text][Formula: see text]M with a low detection limit of 5 5.69[Formula: see text][Formula: see text]M. The characteristics of the electrode are studied in terms of repeatability, reproducibility and stability with RSD values 1.59%, 2.04% and 5.33%. Two varieties of black tea were taken and successfully segregated using principal component analysis (PCA) tool with a separability index of 13.14. This study explicitly demonstrates a significant improvement in electrochemical detection of THP in tea samples using samarium oxide nanoparticles infused in the graphite paste. The novelty of this research work lies in the fact that these fabricated electrodes can be dipped into the tea samples directly with no pre-treatment, hence an easy estimation of the quality of tea sample is possible.

A Promising Analytical Method has been Crafted, Validated, and Quantified for Estimating Theophylline Utilizing UV Spectroscopic and RP-HPLC Techniques in Conjunction with Stress Degradation Studies to Pinpoint Deterioration

Introduction: The current study aimed to develop and assess UV-spectrophotometric (zero order, first order, second order, area under the curve) and RP-HPLC methods for estimating theophylline in its pharmaceutical dosage form.
 Methods: A less toxic solvent composition of acetonitrile and 0.1% orthophosphoric acid (25:75 v/v) is used as a mobile phase and diluent for developing both UV-spectroscopic and RP-HPLC techniques. Shimadzu Prominence LC-20A Modular HPLC system with a C18 column (250 × 4.6 mm; 5 µm) was used to develop the RP-HPLC method.
 Results: Method A is a zero-order spectrophotometric method for determining theophylline at 271 nm, and the correlation coefficient in the linearity study was found to be 0.9958, LOD, and LOQ are 0.52 and 1.71 µg/mL. Method B is a first-order spectrophotometric method for determining theophylline at 258 nm, and the correlation coefficient in the linearity study was found to be 0.9983, LOD, and LOQ are 0.46 and 1.51 µg/mL. Method C is a second-order spectrophotometric method for determining theophylline at 218 nm, and the correlation coefficient in the linearity study was found to be 0.9941, LOD, and LOQ are 0.38 and 1.25 µg/mL. Method D is an area under the curve spectrophotometric method for determining theophylline at 260 to 282 nm, and the correlation coefficient in the linearity study was found to be 0.9978, LOD, and LOQ are 0.57 and 1.88 µg/mL. Method E is the RP-HPLC method for the determination of theophylline at the retention time of 2.814 min, and the correlation coefficient in the linearity study was found to be 0.9923, LOD, and LOQ are 0.78 and 2.57 µg/mL. Studies on stress degradation show that oxidation and acid degradation mostly impact theophylline solutions.
 Conclusion: Theophylline can be determined using the proposed approach, which is convenient, precise, affordable, and reproducible.

Determination of Caffeine, Theobromine, and Theophylline by HPLC-DAD in Beverages Commonly Consumed in Lima, Peru.

The purpose of this study was to determine the content of caffeine, theobromine, and theophylline by high-performance liquid chromatography with diode-array detection (HPLC-DAD) in beverages commonly consumed in Lima, Peru. The samples were divided into 6 groups (herbal teas, coffee powder, chocolate milks, soft drinks, sports drinks, and energy drinks) which included the five most commonly consumed beverages of the different groups. Caffeine was mainly identified in the soft drink and energy drink groups, with the latter having a more significant value (10.38 ± 0.01 vs. 95.50 ± 3.48 mg/L, respectively). In herbal teas, caffeine showed the highest content (0.47 ± 0.01 to 4.91 ± 0.05 mg/L), despite theophylline being a characteristic compound of tea leaves. Sports drinks presented very low caffeine levels (0.03 ± 0.01 to 0.05 ± 0.01 mg/L), and theobromine (0.48 ± 0.01 to 6.00 ± 0.02) was also identified. Caffeine (4.09 ± 0.01 to 5.70 ± 0.01 mg/L) and theobromine (1.70 ± 0.01 to 12.24 ± 0.01 mg/L) were found in the five commercial brands of chocolate milk evaluated. Moreover, the group of coffee powder samples had the highest level of caffeine content (49.25 ± 0.24 to 964.40 ± 4.93 mg/100 g). The results obtained in this study provide reliable information on the composition and quantification of methylxanthines in the beverages most consumed in Lima and impact consumer knowledge.

Optimization of Micelle-mediated extraction and cloud point pre-concentration for the simultaneous determination of caffeine, theophylline and theobromine in Green tea leaves by High Performance Thin Layer Chromatography

Optimization of Micelle-mediated extraction and cloud point pre-concentration for the simultaneous determination of caffeine, theophylline and theobromine in Green tea leaves by High Performance Thin Layer Chromatography

Applications of Six Sigma and Quality by Design Approach in UHPLC Method Development for Simultaneous Assessment of Eight Bronchodilators in Drug Substance

This work portrays the development and validation of a simple and fast UHPLC method for the simultaneous estimation of eight bronchodilators in the drug substance. Process and performance capability (Cpk, Ppk, PPM) studies were conducted by which it may easily conclude how well developed method meeting the requirements. Integration of quality by design (QbD) concept to analytical method development was also discussed. The temperature and mobile phase interaction on chromatographic separation were studied using design of experiments (DoE). Using the QbD and design of experiments (DoE) as combination, a design space was established for developed method. The developed method facilitates the quantitative determination of clenbuterol hydrochloride, fluticasone, formoterol, glycopyrrolate, levalbuterol, metaproterenol, salmeterol and theophylline as a drug substance. All the compounds were separated within 20 min using analytical column X-Bridge BEH C18; (100 × 2.1 mm, 2.5 μ) mobile phase consisted variable mixtures of mobile phase A (10 mM ammonium acetate pH 4.5) and mobile phase B (methanol) with the gradient elution, column temperature 30 ºC, mobile phase flow rate 0.2 mL min/min, wavelength of detection 234 nm.

Determination of caffeine, paraxanthine, theophylline and theobromine in premature infants by HILIC-MS/MS

Aim: Caffeine is a central nervous system stimulant, used to treat apnea of prematurity. A hydrophilic interaction chromatography-tandem mass spectrometry(HILIC-MS/MS) approach was developed to detect caffeine, paraxanthine, theophyllineand theobromine in premature infants. Method: Protein precipitation of plasma samples (10μl) was carried out by treating with acetonitrile containing caffeine-13C3. The separation was carried out on an ACQUITY HPLC® BEH HILIC column. Caffeine and its metabolites were quantified by multiple reaction monitoring modes with positive electrospray ionization. Results: The established method had a good linear relationship in the range of 0.0600-60.0μg/ml for caffeine, 0.0250-7.50μg/ml for theobromine and0.0150-4.50μg/ml for paraxanthine and theophylline. Conclusion: A HILIC-MS/MS method was developed and validated to determine caffeine and its major metabolites in plasma of premature infants.

A sensing platform based on zinc-porphyrin derinative in hexadecyl trimethyl ammonium bromide (CTAB) microemulsion for highly sensitive detection of theophylline

A new porphyrin-based sensing platform in hexadecyl trimethyl ammonium bromide (CTAB) microemulsion is developed for highly sensitive detection of theophylline. In this sensing system, the zinc-porphyrin-cinnamic acid conjugate (Zn-TPPCA) works as fluorescence probe while theophylline can decrease fluorescence intensity of the probe. Further studies indicate the linear relationship between the fluorescence quenching value and the concentration of theophylline within a given range. And the introduction of CTAB microemulsion can greatly enhance sensibility and stability of this detecting system and facilitate the detection of theophylline. On the basis above, a highly sensitive sensing platform for theophylline is created with a low limit of detection (LOD) of 0.0083 μg mL−1 under the optimal detection conditions. And further application of this method in determination of commercially available theophylline preparation shows excellent results. Subsequent studies on quenching mechanism indicate that static quenching appears between Zn-TPPCA and theophylline. Therefore, this work provides not only a highly sensitive method for determination of theophylline but also further evidence for creation of biosensors for drugs with porphyrin derivatives.

Quality by Design (QbD) Approach to Analytical RP-HPLC Method Development and its Validation of Etophylline & Theophylline

A convenient, accurate, rapid, precise and sensitive RP-HPLC method involving UV detection was developed and validated for determination and quantification of Etophylline and Theophylline in tablet dosage form. The determination was carried out on a Kromasil C18 (250 × 4.6 mm, 5 μm) column using filtered and degassed mixture of methanol: Buffer pH 4.5 (94: 06 v/v) as mobile phase at a flow rate of 1 ml/min and effluent was monitored at 272 nm. The retention time for Etophylline was 1.535 min and for Theophylline2.477 min. Etophylline and Theophylline showed a linear response in the concentration range of 10-50μg/ml and 20-100μg/ml individually. The correlation co-efficient for Etophylline and Theophylline was 0.9993 and 0.9998, respectively. The method was validated in terms of linearity, precision, accuracy, specificity, robustness and system suitability. The proposed method can be useful in the quality control of bulk manufacturing and pharmaceutical dosage forms.

EDTA salt modified carbon paste electrode for square wave voltammetric determination of theophylline in pharmaceutical tablet formulation.

In this study, a square wave voltammetric method for determination of theophylline in tablet formulation based on EDTA salt modified carbon paste electrode is presented. CV, FT-IR, and EIS results confirmed modification of the carbon paste with EDTA salt. In contrast to the unmodified carbon paste electrode, the modified carbon paste electrode showed irreversible oxidation of theophylline with considerable current enhancement. Investigation of the effect of scan rate on the Ip and Ep response of the modified electrode for theophylline revealed predominantly diffusion controlled oxidation kinetics. Under the optimized conditions, square wave oxidative peak current of theophylline in pH 7.0 PBS showed linear dependence on concentration in the range 10–200 μM with determination coefficient (R2), limit of detection, and limit of quantification of 0.99782, 0.0257 μM, and 0.0857 μM, respectively. Detection of an amount of theophylline in the analyzed tablet formulation with 1.85% error from its nominal content (120 mg/tablet) confirmed the accuracy of the developed method. Spike and interference recovery results of 98.59%, and 95.7–100%, respectively validated the applicability of the developed method for determination of theophylline content in tablet samples.

Ultrasound-assisted surfactant-enhanced emulsification microextraction and determination of caffeine and theophylline in human plasma and cocoa powder

Ultrasound-assisted surfactant-enhanced emulsification microextraction and determination of caffeine and theophylline in human plasma and cocoa powder

APPLICATION OF TWO ADVANCED DERIVATIVE SPECTROPHOTOMETRIC METHODS FOR SIMULTANEOUS ESTIMATION OF SALBUTAMOL SULPHATE, AMBROXOL HYDROCHLORIDE AND THEOPHYLLINE IN PURE AND COMMERCIAL FORMULATIONS

Objective: Two advanced spectrophotometric methods have been proposed for the simultaneous determination of Salbutamol sulphate, Ambroxol hydrochloride and Theophylline in pure and pharmaceutical formulations. The proposed methods exclude the hectic steps of time-consuming sample preparations or purification or separation steps. There is no any spectrophotometric method has been avail for simultaneous estimation of the ternary mixture containing Salbutamol sulphate, Ambroxol hydrochloride and Theophylline.
 Methods: The methods are derivative ratio spectra zero-crossing method and double divisor ratio spectra derivative method respectively. Both the methods are found to be rapid, accurate, precise, reliable and economical as well. The developed methods show best results in terms of linearity, accuracy, precision, limit of detection and limit of quantification for standard laboratory mixtures of pure drugs and marketed formulations.
 Results: The range for Salbutamol sulphate, Ambroxol hydrochloride and Theophyllineare found to be 1-35 µg ml-1, 5-35 µg ml-1and 6-60 µg ml-1 respectively. For the derivative ratio spectra zero-crossing method, the values of the limit of detection are found to be 0.3161 µg ml-1, 0.2212 µg ml-1 and 0.2910 µg ml-1 and the values limit of quantification are found to be 0.9571 µg ml-1, 0.7412 µg ml-1 and 0.9671 µg ml-1 for Salbutamol sulphate, Ambroxol hydrochloride and Theophylline respectively. For double divisor ratio spectra derivative method, limit of detection values is found to be 0.3251 µg ml-1, 0.2591 µg ml-1 and 0.2640 µg ml-1 and the limit of quantification values are found to be 0.9870 µg ml-1, 0.8650 µg ml-1 and 0.8812 µg ml-1 for Salbutamol sulphate, Ambroxol hydrochloride and Theophylline respectively.
 Conclusion: The common excipients and additives did not interfere in the determinations of any of the drugs while being analysed for commercial formulations. These two spectrophotometric methods, which determine SS, AH, and THE simultaneously, are simple, specific, accurate, precise, rapidly, and economically, indicating that they can be used routinely in pharmaceutical analysis. As a result, derivative spectrophotometry may be used effectively for the simultaneous determination of SS, AH and THE in the combined dosage forms without any prior separation of individual drugs.

Green synthesis of carbon nanodots for direct and rapid determination of theophylline through fluorescence turn on–off strategy

Green synthesis of carbon nanodots for direct and rapid determination of theophylline through fluorescence turn on–off strategy

Poly(aquachlorobis(1,10–phenanthroline)copper(II)iodidemonohydrate)/GCE for simultaneous determination of caffeine and theophylline in human serum, tea, and tablet samples

This paper presents metal complex based polymer film modified electrode for simultaneous determination of caffeine, and theophylline. Potentiodynamic fabrication of poly(aquachlorobis(1,10– phenanthroline)copper(II)iodidemonohydrate) modified glassy carbon electrode (poly(ACP 2 CuIH)/GCE) was verified using cyclic voltammetric and electrochemical impedance spectroscopic techniques. In contrast to the unmodified glassy carbon electrode, the poly(ACP 2 CuIH)/GCE in equi-molar mixture of theophylline and caffeine revealed sufficiently separated oxidative peaks with much enhanced peak current showing electrocatalytic property of the polymer film towards the oxidation of theophylline and caffeine. Under optimized solution pH and square wave voltammetric parameters, oxidative peak current response of poly(ACP 2 CuIH)/GCE showed linear dependence on the concentration of caffeine and theophylline in the concentration range 1.0–200.0 µM with limit of detection 8.92 × 10 -3 µM for theophylline, and 1.02 × 10 -2 µ M for caffeine. Spike recovery in the range 97.0-102.4% for theophylline, and 95.4-100.0% for caffeine, interference recovery in the range 96.0–101.0% for theophylline, and 95.7–104.3% for caffeine, agreement of the detected amounts of theophylline and caffeine in tablet samples with the nominal values, and stability of the modified electrode all validated the developed method for simultaneous determination of theophylline and caffeine in wide range of real samples. The method was applied for simultaneous determination of both theophylline and caffeine in three tea brands (Black lion, Addis, and Wush wush), pharmaceutical tablet brands (Panadol extra, and Theodrine), and human blood serum samples making the method an excellent candidate.

Evaluation of Electrochromic Properties of Polypyrrole/Poly(Methylene Blue) Layer Doped by Polysaccharides.

Polypyrrole (Ppy) and poly(methylene blue) (PMB) heterostructure (Ppy-PMB) was electrochemically formed on the indium tin oxide (ITO) coated glass slides, which served as working electrodes. For electropolymerization, a solution containing pyrrole, methylene blue, and a saccharide (lactose, sucrose, or heparin) that served as dopant was used. The aim of this study was to compare the effect of the saccharides (lactose, sucrose, and heparin) on the electrochromic properties of the Ppy-PMB layer. AFM and SEM have been used for the analysis of the surface dominant features of the Ppy-PMB layers. From these images, it was concluded that the saccharides used in this study have a moderate effect on the surface morphology. Electrochromic properties were analyzed with respect to the changes of absorbance of the layer at two wavelengths (668 nm and 750 nm) by changing the pH of the surrounding solution and the potential between +0.8 V and −0.8 V. It was demonstrated that the highest absorbance changes are characteristic for all layers in the acidic media. Meanwhile, the absorbance changes of the layers were decreased in the more alkaline media. It was determined that the Ppy-PMB layers with heparin as a dopant were more mechanically stable in comparison to the layers doped with lactose and sucrose. Therefore, the Ppy-PMB layer doped with heparin was selected for the further experiment and it was applied in the design of electrochromic sensors for the determination of three xanthine derivatives: caffeine, theobromine, and theophylline. A linear relationship of ΔA (∆A = A+0.8V − A−0.8V) vs. concentration was determined for all three xanthine derivatives studied. The largest change in optical absorption was observed in the case of theophylline determination.

A study on determination of theophylline in plasma and urine sample using electromembrane extraction combined with high-performance liquid chromatography–ultraviolet

A study on determination of theophylline in plasma and urine sample using electromembrane extraction combined with high-performance liquid chromatography–ultraviolet