Bioanalytical method development and validation for determination of metoprolol tartarate and hydrochlorothiazide using HPTLC in human plasma

A simple, sensitive, rapid and economic chromatographic method has been developed for determination of metoprolol tartarate and hydrochlorothiazide in human plasma using paracetamol as an internal standard. The analytical technique used for method development was high-performance thin-layer chromatography. HPTLC Camag with precoated silica gel Plate 60F254 (20 cm×10 cm) at 250 µm thicknesses (E. Merck, Darmstadt, Germany) was used as the stationary phase. The mobile phase used consisted of chloroform: methanol: ammonia (9:1:0.5v/v/v). Densitometric analysis was carried out at a wavelength of 239 nm. The rf values for hydrochlorothiazide, paracetamol and metoprolol tartarate were 0.13±0.04, 0.28±0.05, 0.48±0.04, respectively. Plasma samples were extracted by protein precipitation with methanol. Concentration ranges of 200, 400, 600, 800, 1000, 1200 ng/mL and 2000, 4000, 6000, 8000, 10000, 12000 ng/mL of hydrochlorothiazide and metoprolol tartarate, respectively, were used with plasma for the calibration curves. The percent recovery of metoprolol tartarate and hydrochlorothiazide was found to be 77.30 and 77.02 %, respectively. The stability of metoprolol tartarate and hydrochlorothiazide in plasma were confirmed during three freeze-thaw cycles (-20 ºC) on a bench for 24 hours and post-preparatively for 48 hours. The proposed method was validated statistically and proved suitable for determination of metoprolol tartarate and hydrochlorothiazide in human plasma

Interchangeability of gabapentin generic formulations in the Netherlands: a comparative bioavailability study

Item does not contain fulltextTo investigate the so-called "drift" with generic-generic drug substitution, a single-dose, four-way crossover comparative bioavailability study was performed involving 24 healthy subjects and three generic and one branded formulation of a tablet containing 800 mg gabapentin as test medication. The results showed that the 90% confidence intervals (CIs) for the area under the drug concentration-time curve (AUC0-t) and for the peak drug concentration (Cmax) were within the acceptance range of 80-125% for all comparisons. The safety profiles of the different gabapentin formulations were comparable. To conclude, all three generic formulations of gabapentin were found to be bioequivalent with the branded formulation and with each other, indicating that the formulations are interchangeable. These results strongly indicate the absence of "drift" with gabapentin generic-generic substitution.Clinical Pharmacology & Therapeutics (2013); 94 4, 519-524. doi:10.1038/clpt.2013.108

The family Donacidae (Bivalvia: Tellinoidea) in Thai waters

The species belonging to the family Donacidae living in Thailand waters are herein revised. After an exhaustive bibliographical search, 29 nominal species were found from this area. Materials from several institutions and specimens collected during fieldwork in Phuket and the Gulf of Thailand were studied. All the type materials were illustrated and redescribed. Details of the type localities, repositories, habitats and biogeographical distribution are discussed. In addition, some collected specimens and the type materials of the valid species and synonyms are illustrated. Currently, eight valid species are confirmed as living in Thailand waters: Donax (Deltachion) spinosus Gmelin, 1791, Donax (Deltachion) semigranosus (Dunker, 1877), Donax (Dentilatona) incarnatus Gmelin, 1791, Donax (Hecuba) scortum (Linnaeus, 1758), Donax (Latona) cuneatus Linnaeus, 1758, Donax (Latona) faba Gmelin, 1791, Donax (Latona) solidus Spengler, 1798 and Donax (Paraserrula) introradiatus Reeve, 1855. The presence of Donax (Deltachion) semisulcatus Hanley, 1843, Donax brazieri Smith, 1892, Donax (Tentidonax) veruinus Hedely, 1913 and Donax victoris Fischer-Piette, 1942 in Thailand waters remains uncertain. These species have been reported in the study area in the literature, but they were not sampled during this study.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Printrakoon, Cheewarat. Kasetsart University; Tailandi