ABSTRACT
Oxidized diphenylamine is newly utilized as a redox spectrophotometric reagent for the determination of six pharmaceutically important thiol and thioamide drugs named: acetylcystiene, captopril, carbimazole, propylthiouracil, thiopental sodium, and tiopronin. The method is based on measurement of the decrease in absorption intensity of the oxidized diphenylamine [diphenylbenzidine violet, lambda max = 580 nm] reagent as a result of the reduction effect of the analysed drugs This reagent was instantaneously prepared by the oxidation of diphenylamine using ferric sulphate in sulphuric acid medium. The molar ratio of the chromogen reagent was determined to be 2:1; diphenylamine: iron [III]. The decrease in colour intensity was found to be quantitatively dependent on drug concentration. Experimental variables including reagent concentration, acid type and concentration, dilution solvent, reaction time, temperature and stability were studied and optimized. Validation parameters including linearity range, detection and quantitation limits, precision, selectivity and robustness were evaluated. The proposed method was found to be simple, sensitive and accurate one indicated by the studied validation parameters. Good recoveries [98.0 +/- 0.14 - 100%, +/- 0.98] were obtained by the suggested method and it was applied for the determination of the studied drugs in many pharmaceutical dosage forms available in the local market. Good agreement, indicated by acceptable t- and F- tests, was found between results obtained by the suggested method and those obtained by the reported or pharmacopoeial methods
Subject(s)
Chemistry, Pharmaceutical , Sulfhydryl Compounds , Thioamides , SpectrophotometryABSTRACT
In this study, 25 cases of vertebral body metastases were treated, their age average was 54 years [range 41-69 years]. Nineteen cases had neurological deficits due to vertebral collapse. Six cases were neurologically free and had severe back pain due to vertebral collapse and instability not responding to the conservative treatment. The primary lesion could be detected in 19 cases. There were five cervical lesions, thirteen thoracic and seven lumbar lesions. All cases were treated by anterior decompression, reconstruction by bone cement in 22 cases and bone graft in 3. Anterior AO plate fixation was done for 19 cases. In the other six cases, transpedicular fixation had to be used in another stage. Three cases died within the first month after surgery. A marked pain relief occurred in 20 patents, neurological improvement by at least one Frankel grade occurred in 13 patients and the ambulatory status was improved from 40% of the patients preoperatively to 64% after surgery. The average survival time at the last follow up was 14.4 [0.25-39] months