Search

Antifibrinolytic tranexamic acid (TRX) suppresses plasminogen activation to plasmin in a competitive way. TRX is approved for the management of heavy menstrual periods, hereditary angioedema, hemophilia, postpartum hemorrhage, surgery, tooth extraction, and severe blood loss after acute trauma. Here, the practical use of an isoindole derivative was established for a novel, easy‐to‐use, and affordable TRX assay. In the presence of a molecule containing a sulfhydryl group (2‐mercaptoethanol) 0.02% v/v, the primary amine moiety in TRX allows its combination with o‐phthalaldehyde to produce a luminous product. Excitation (338.8 nm) and emission (433.9 nm) wavelengths were used to monitor the isoindole fluorophore yield, and each operational variable was carefully examined and adjusted. The calibration graph was constructed with fluorescence intensity versus TRX concentration, excellent linearity was observed at concentrations between 40 and 950 ng/ml, and limit of detection and limit of quantitation were 41.3 and 13.6 ng/ml, respectively. The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines were used to validate the method. The developed method for TRX assay in various dosage forms and urine was successfully implemented and was shown to be an effective, simple, and quick replacement for the TRX assay in clinical trials and quality control. [ABSTRACT FROM AUTHOR]

Herein, we developed a new pencil graphite ion-selective electrode strategy for the broadly used erectile dysfunction medication, sildenafil citrate (SC, vitamin V), for its automated potentiometry and potentiometric titration profiling in marketed tablets and human urine samples. The method was based on ion-pair complexation between SC and sodium tetraphenylborate (Na-TPB) or phosphotungstic acid (PTA), embedded into a pencil-fabricated graphite sensor electrode coated with poly(vinyl chloride, PVC) matrix, which is pre-plasticized with two different pre-studied plasticizers. The modern fabricated electrodes have a proven fast near-Nernstian response for SC over the concentration range of 1.0 × 10−6 to 1.0 × 10−2 and 1.0 × 10−5 to 1.0 × 10−2 M, with LODs of 6.5 × 10−7 and 5.5 × 10−6 over a pH 3–6 for (SC-TPB)- and (SC-PTA)-based membrane sensors, of O-nitrophenyl octyl ether (O-NPOE) and dioctyl phthalate (DOP), respectively. The selectivity coefficients for different interferents, including many inorganic cations, sugars, and/or nitrogenous compounds, were tested and confirmed. Applications of the proposed method were conducted on the determination of SC in its tablets and urine samples under the proper conditions. The percent recovery values were compared with those obtained by an official method and showed an RSD ≤ 0.3% (n = 5). [ABSTRACT FROM AUTHOR]

[Display omitted] • The retention of four 2-arylpropionic acid derivatives on heat-resistant stationary phase was studied. • Extra-thermodynamic investigations were conducted. • Enthalpy-entropy compensation has been proven as extra-thermodynamic relationship. • A high-temperature liquid chromatography method was developed and validated. • Successful application of the method to tablets dosage forms and human urine samples was achieved. A study of the retention behavior of four frequently prescribed anti-inflammatory 2-arylpropionic acid derivatives on a reversed-phase thermostable stationary phase was conducted. Extra-thermodynamic investigations were carried out over the temperature range of 303–338 K. A modified van't Hoff analysis was applied to assess the enthalpy, entropy, and Gibb's free energy changes that take place during the mass transfer from the mobile phase to the stationary phase. It has been proven that enthalpy–entropy compensation exists as an extra-thermodynamic relationship. The effect of molecular structures of the investigated drugs on thermodynamic and retention behaviors was also explored. A validated high-temperature liquid chromatography method was established for the separation and analysis of ketoprofen, naproxen, diclofenac, and ibuprofen in pharmaceutical formulations and human urine with %recoveries within the range of 90.1–105.6 % and standard deviation not exceeding ±4.1% in all cases. The developed method greenness was positively assessed by the analytical eco-scale score tool. [ABSTRACT FROM AUTHOR]