new spectrophotometric method for the determination of methyldopa

A new, simple and low cost spectrophotometric method for the determination of methyldopa in pharmaceutical preparations was developed. The method was based on the coupling of methyldopa with 2,6-dichloroquinone-4-chlorimide [DCQ]. The absorbance maximum [lambda max] of the resulted colored product was at 400nm. Different buffers were used to determine the optimal pH for the reaction. 1% w/v acetate buffer with pH 8.0 gave the optimal pH required for the reaction. Of the different solvents tried, water and ethanol were found to be the most suitable solvents. Beer's law was obeyed in concentration range of 4-20 micro g/ml methyldopa. The correlation coefficient was found to be [r=0.9975]. The limit of detection and limit of quantification were 1.1 micro g/ml and 3.21 micro g/ml, respectively. The reaction ratio between methyldopa and DCQ was studied and found to be 1:3. The work included the study of the possible interference of hydrochlorothiazide found in combination with methyldopa tablets. The method was validated and results obtained for the assay of two different brands of methyldopa tablets were compared with the B.P. method [colorimetric]. The repeatability and reproducibility of the developed method were evaluated and the obtained results quoted. The derivative formed as a result of the reaction of methyldopa with DCQ was isolated and its possible mechanistic pathway was suggested

Antischistosomal effects of praziquantel, its alkaline hydrolysis and sun decomposed products on experimentally S. mansoni infected albino mice. [A] efficacy assessment based on clinicopathological findings

The antischistosomal activity of praziquantel [PZQ], its alkaline hydrolysis product [HP] and its sun decomposed [SD] products was investigated in S. Mansoni experimentally infected mice. The evaluation depended on the degree of the clinicopathological changes. The obtained results revealed that, PZQ, HP and SD induced a partial suppression of worm fecundity as judged by the significant reduction in eggs per gram of feces in comparison with the infected untreated control. The effect on tissue egg deposition in the treated groups was comparable with the infection of the untreated control. Worm recovery showed a great reduction in the number of worms for SD [47.6%] and HP [28.6%] compared with PZQ [16.6%] treated groups. So, the former two compounds have the superior antischistosomal activities. Glutamate pyruvate transaminase [GPT] and glutamate oxaloacetate transaminase [GOT] concentrations were measured. The GOT values for all treated groups were significantly higher than those for the healthy control group. The SD group enzyme concentration was even higher than the infected untreated control. The GPT values of all groups were greater than the uninfected control and the difference was significant for the infected untreated, PZQ and the SD treated groups