Gabapentin determination in human plasma and capsule by coupling of solid phase extraction, derivatization reaction, and UV-Vis spectrophotometry

Gabapentin is an anticonvulsant widely used in the treatment of epilepsy. No peculiar chromophore is available on the gabapentin moiety for direct analysis by absorption spectrophotometry. A sensitive spectrophotometric method for the determination of gabapentin in bulk, pharmaceutical formulations and human plasma has been developed. In this method, gabapentin directly derivatized with vanillin and analyzed without any extraction in bulk and pharmaceutical dosage form and in plasma samples, it was extracted with a reversed-phase solid-phase extraction [SPE] cartridge followed by derivatization with vanillin. Analysis was performed by a spectrophotometer system. The quantitation limit of gabapentin in human plasma was 0.8 mg/L. The method was linear over the concentration range of 10.0-90.0 mg/L and 0.8-10.0 mg/L for pharmaceutical dosage form and plasma, respectively. The method was precise [relative standard deviation, RSD <1.20%] and accurate [relative mean error <5.5%] for both pharmaceutical dosage form and plasma samples. Mean absolute recoveries were 94.5% for plasma

Food additives and Hymenolepis nana infection: an experimental study

The effect of sodium benzoate [SB] on the pathogenesis of Hymenolepis nana [H. nana] and its neurological manifestations was studied in the present work. One hundred and thirty five mice were classified into three groups. GI: received SB alone, GII: received SB before and after infection with H. nana and GIII: infected with H. nana. All groups were subjected to parasitological, histopathological, immunohistochemical and biochemical assays. The results revealed a significant decrease in TL-4 serum level with a significant increase in gamma amino butyric acid [GABA] and decrease in zinc brain levels in GI, while GII showed non significant increase in IL-4 level that resulted in a highly significant increase in the mean number of cysticercoids and adult worms with delayed expulsion as compared to GIII. This was reflected on histopathological and immunohistochemical changes in the brain. Also, there was a highly significant increase in GABA and decrease in zinc brain levels in GII to the degree that induced behavioral changes. This emphasizes the possible synergistic effect of SB on the neurological manifestations of H. nana and could, in part, explain the increased incidence of behavioral changes in children exposed to high doses of SB and unfortunately have H. nana infection

GABA changes in narcotic addiction

Changes in the plasma concentration of 8-amino butyric acid [GABA], the main inhibitory inhibitory neurotransmitter were studied in different types of narcotic drug addiction. Forty four adult male addicts were investigated. Simultaneously, urine analysis for detection of opiates, barbiturates and cannabmoids excreted during withdrawal and after withdrawal periods was done. Plasma concentration of GABA, showed a highly significant rise [P > 0.001] in addicts, when compared to normal healthy controls. The increase of mean values of GABA showed direct relation to the duration of addiction, although statistically nonsignificant. The rise of GABA was more pronounced in barbiturates than in opiates addiction during the withdrawal period, after which a decline of concentration was observed in barbiturate addicts, but still above the normal level, while opiate addicts showed a maintained significant rise. Combined narcotic addiction showed higher level of GABA, except in case of barbiturates with cannabinoids, indicating different mechanisms of drug interaction

Asociación entre los niveles de amonio y GABA plasmáticos y el grado de encefalopatía hepática / Association of plasma ammonia and GABA levels and the degree of hepatic encephalopathy

Varias substancias presumiblemente tóxicas tales como el amonio se han implicado en la patogenia de la encefalopatía hepática porto-sistémica (EPS). Recientemente se ha propuesto la hipótesis del ácido gama-aminobutríco (GABA) donde el aumento del tono gabaérgico y la presencia de uno o más ligandos para el receptor GABA/benzodiacepínicos juegan un papel central. Con el objeto de investigar la asociación entre las elevaciones plasmáticas de amonio y GABA y el grado de encefalopatía hepática, estudiamos tres grupos de pacientes con enfermedad hepática que cursaban con episodio de EPS aguda espontánea o precipitada por hemorragia gastrointestinal o sepsis, en quienes se determinaron los niveles de amonio y GABA en plasma antes y después de tratamiento convencional con lactulosa. La EPS se valoró mediante el índice de EPs incluyendo pruebas del estado mental y electroencefalograma (EEG) entre otras. Los niveles de GABA en plasmas se encontraron significativamente elevados en pacientes con EPS pura (458+-108 pmol/mL) comparados con sujetos sanos (110+-23 pmol/mL)(p<0.01) aunque no se encontró correlación entre las concentraciones de GABA y el grado de encefalopátía. Sin embargo, los cambios en los niveles de amonio correlacionaron con los cambios en el índice de EPS (r=0.56;p<0.02) y con las alteraciones en el EEG (r=0.65;

Do ácido gamma-aminobutírico (GABA) e das convulsöes / Gama-aminobutyric acid (GABA) and convulsions

Apresenta-se uma revisäo sobre as açöes inibitórias do GABA, seu metabolismo e envolvimento no processo inibitório