No abstract

No abstract

A rapid and accurate spectrofluorimetric method for the determination of pomalidomide was developed and validated based on the measurement of its native fluorescence without the need for any derivatization and separation for the first time.The fluorescence intensity of the drug in acetonitrile solution allowed precise detection at 460 nm after excitation at 296 nm. The calibration curve was linear in the concentration range 31.0-500.0 ng/ml. Limit of detection and limit of quantification were found to be 8.04 and 24.36 ng/ml, respectively. Sensitive results allowed the drug to be detected with good recovery (75.46-109.72%) in human plasma and urine using the developed method. The proposed method was validated in terms of linearity, sensitivity, precision, accuracy, recovery, and stability parameters. Pomalidomide was subjected to degradation under various stress conditions (hydrolytic, oxidative and thermal) to demonstrate that the method was stable, indicating and identifying possible degradation products. In addition, the drug was exposed to electrochemical degradation using the chronoamperometry technique for the first time. Characterization of pomalidomide degradation products obtained because of oxidative degradation and electrochemical degradation was carried out using attenuated total reflection Fourier transform infrared spectroscopy, mass spectrometry and high performance liquid chromatography − mass spectrometry methods and possible structures were proposed. K E Y W O R D Selectrochemical oxidation, forced degradation study, plasma, pomalidomide, spectrofluorimetry, urine

Simple, rapid spectrophotometric, and reverse-phase high performance liquid chromatographic methods were developed for the concurrent analysis of 17-beta-estradiol (ESR) and drospirenone (DRS). The spectrophotometric method was based on the determination of first derivative spectra and determined ESR and DRS using the zero-crossing technique at 208 and 282 nm, respectively, in methanol. The linear range was 0.5–32.0 µg·mL−1 for DRS and 0.5–8.0 µg·mL−1 for EST. The limit of detection (LOD) values were 0.14 µg·mL−1 and 0.10 µg·mL−1 and limit of quantification (LOQ) values were 0.42 µg·mL−1 and 0.29 µg·mL−1 for ESR and DRS, respectively. The chromatographic method was based on the separation of both analytes on a C18 column with a mobile phase containing acetonitrile and water (70 : 30, v/v). Detection was performed with a UV-photodiode array detector at 279 nm. The linear range was 0.08–2.5 µg·mL−1 for DRS and 0.23–7.5 µg·mL−1 for EST. LOD values were 0.05 µg·mL−1 and 0.02 µg·mL−1 and LOQ values were 0.15 µg·mL−1 and 0.05 µg·mL−1 for ESR and DRS, respectively. These recommended methods have been applied for the simultaneous determination of ESR and DRS in their tablets.

Summary. A precise and sensitive reversed phase high-performance thin-layer chromatography (RP-HPLC) method was developed for the determination of nilotinib (NTB) in spiked plasma, urine, and pharmaceutical capsule formulation. The method was based on derivatization NTB with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in the borax buffer (pH 9). The method employs an isocratic elution using acetonitrile and 10 mM orthophosphoric acid (40:60 v/v) as a mobile phase and an C 18 column (4.6 mm × 250 mm, 5 µm, Waters Symmetry), with a fluorescence detector (λ ex : 447 nm, λ em : 530 nm). The method validation was performed with respect to linearity, recovery, accuracy, precision, and stability. The linear ranges were 100-600 ng mL −1 in standard solution, plasma, and urine. Correlation coefficients (r 2 ) were higher than 0.9997 for all of the analytes, indicating good linear relationship. The percentage recovery was 87.89% for plasma, 95.35% for urine, and 96.07% for capsules.