Simultaneous determination of dantrolene and paracetamol in human plasma by liquid chromatography tandem mass spectrometry

Sensitive and selective determination of paracetamol in antipyretic children's syrup with a polyglycine modified glassy carbon electrode

A sensitive and selective electrochemical sensor for the determination of paracetamol (acetaminophen) is proposed based on a polyglycine-coated glassy carbon electrode. The electrochemical behavior of paracetamol was studied by cyclic voltammetry and differential pulse voltammetry. Under optimal experimental conditions, the peak oxidation current of paracetamol increases linearly in the range of 0.5-75 μM. The limit of detection of paracetamol was 0.03 μM and the limit of quantitation was 0.09 μM. In addition, modified glassy carbon with polyglycine as the sensor was successfully used for the determination of paracetamol in antipyretic children's syrup samples, with a recovery rate of over 95.3%, showing its great application potential in drug analysis.

Turn-off fluorescence of S,N-doped carbon dots for determination of two nitro-containing drugs in dosage forms and human plasma

This study describes the development of an environmentally-friend optical nanosensor for the rapid spectrofluorimetric assessment of two nitro-compounds, namely nitrofurantoin and dantrolene in their dosage forms and plasma samples. A one-step synthetic technique successfully created very bright water-soluble carbon quantum dots doped with sulfur and nitrogen (S,N-CQDs). Carbon was derived from citric acid, while nitrogen and sulfur were obtained from thiosemicarbazide. The dimensions of the synthesized dots were measured using a high-resolution transmission electron microscope. FT-IR spectroscopy was used to determine which functional groups were located on their surfaces. The nanosensor's fluorescence emission peaked intensely at 415 nm after excitation at 345 nm with a quantum yield of about 0.52. The inherent fluorescence of the nanosensors gradually decreased upon addition of the studied analytes in increasing concentrations. The fluorescence reduction of nanosensor with the concentrations of the investigated drugs demonstrated linear correlation within the ranges of 0.5-8.0 μg/mL and 1.0-10.0 μg/mL with limits of detection of 0.14 μg/mL (0.59 μM) and 0.23 μg/mL (0.73 μM) for nitrofurantoin and dantrolene, respectively. The recommended method was used to determine the concentrations of the investigated drugs in their commercial capsules, with recoveries ranging from 97.90 % to 101.57 % and low percent RSD values less than 2 %. Moreover, the method was adapted for the in-vitro analysis of the two analytes in spiked human plasma samples with % recoveries from 95.20 % to 102.20 %. The mechanism of interaction between each analyte and the dots was also investigated. The selectivity of the approach for measuring analytes concentration in the presence of excipients, co-formulated medications, or co-administered pharmaceuticals was further evaluated through an interference study. The suggested method's validity was evaluated in accordance with ICH criteria.

LC-MS/MS approach for simultaneous assessment of hyoscine N-butyl bromide and ketoprofen in biological fluids and pharmaceuticals

The mixture of hyoscine N-butyl bromide (HBB) and ketoprofen (KTP) is commonly used for the handling of abdominal spasms and pain relief. There are two challenges that restrict the simultaneous assessment of HBB and KTP in biological fluids and pharmaceuticals. The first issue is the difficulty of elution of HBB and the second one is the presence of KTP as a racemic mixture in all pharmaceutical formulations, which obscures its appearance as a single peak. An ultrasensitive and highly efficient liquid chromatography-mass/mass spectrometric (LC-MS/MS) method is designed and validated for the first concurrent assessment of HBB and KTP in spiked human serum and urine, and pharmaceutical formulations. The estimated linearity ranges for HBB and KTP were respectively, 0.5-500 and 0.05-500 ng/ml, with excellent correlation coefficients. Validation results showed that the value of relative standard deviations were <2% for HBB and KTP. The mean extraction recoveries for HBB and KTP were, respectively, 91.04 and 97.83% in Spasmofen® ampoules; 95.89 and 97.00% in spiked serum; and 97.31 and 95.63% in spiked urine. The presented innovative chromatographic approach was utilized for the measurement of trace amounts of coexisting pharmaceuticals in pharmacokinetics studies and routine therapeutic medication monitoring.

A validated LC–MS/MS method for analysis of Cabergoline in human plasma with its implementation in a bioequivalent study: investigation of method greenness

Cabergoline (CAB) is effective prolactin lowering drug. Evaluation of the bioequivalence for the new test product (0.5 mg CAB film-coated tablets) in Egypt is strongly needed for approval of the drug by the official health authority. Therefore, a highly sensitive and rapid (LC–MS/MS) method was validated for CAB analysis in human plasma. CAB was extracted from plasma via diethyl ether using Quetiapine (QUE) as an internal standard. Multiple reaction monitoring (MRM) in positive ion mode was used, m/z 452.3 → 381.2 for CAB and 384.2 → 253.1 for QUE. Separation was accomplished on a reversed-phase C₁₈. FDA procedures for the bio-analytical method were followed. The method was used in the bioequivalence study to compare the test product (0.5 mg CAB) versus Dostinex tablets, on 24 healthy Egyptian volunteers. The total analysis time was 5.5 min for each sample which permits analysis of various samples per day. The linearity range was from 2.00 to 200.00 pg/mL for CAB. LOD and LOQ were found to be 0.5 and 1.6 pg/mL, respectively. The final greenness numerical value was 0.63 using AGREE tool. The results of pharmacokinetic parameter T_max were 2.17, and 2.33 h; for test and reference products, respectively. The generic formulation of test product is considered bioequivalent to the reference product Dostinex 0.5 mg tablets and satisfies the requirements of the Egyptian market. The merits of the method over the previous published methods are low cost; availability of cheap internal standard; rapidness; use of acetonitrile-free solvents mobile phase.