Reagents
Guidelines for the clinical evaluation of herbal medicines attempt to recognize the long and diverse history of traditional medicine in the region and the differences between the diagnostic systems of modern medicine and the various traditional medicines of the member states. Although special considerations may be required, the general principles of the clinical trials of herbal medicines are similar to those applied to synthetic drugs if clinical trial is regarded to be necessary.
Clinical trials of herbal medicines may have two types of objectives. One is to validate the safety and efficacy that is claimed for a traditional herbal medicine. The other is to develop new herbal medicines or examine a new indication for an existing herbal. Medicine or a change of dose formulation, or route of administration. In some cases, trials may be designed to test the clinical activity of a purified or semi-purified compound derived from herbal medicines.
Commercial intravenous (iv) ampoules of imod were obtained from the owner company of imod – parsroos. All ampoules were stored in a cold and dark place and checked for the expiration date, and expired samples were not used. In each experiment, imod was used freshly after vial breakage. A non-nucleoside inhibitor of hiv reverse transcriptase enzyme (nevirapine) and acyclovir (anti-hsv drug) were extracted from commercial tablets and used as positive controls.
A simple, rapid and environmentally friendly sequential injection analysis system employing natural extract reagents was developed for the determination of acetic acid following an acid–base reaction in the presence of an indicator. Powdered lime and turmeric were utilized as the natural base and indicator, respectively. Mixing lime and turmeric produced an orange to reddish-brown color solution which absorbed the maximum wavelength at 455 nm, with absorbance decreasing with increasing acetic acid concentration. Influential parameters including lime and turmeric concentrations, reagent and sample aspirated volumes, mixing coil length and dispensing flow rate were investigated and optimized. A standard calibration graph was plotted for 0–5.0 mmol/l acetic acid with r2 = 0.9925. Relative standard deviations (rsd) at 2.0 and 4.0 mmol/l acetic acid were less than 3% (n = 7), with limit of detection (lod) and limit of quantification (loq) at 0.12 and 0.24 mmol/l, respectively. The method was successfully applied to assay acetic acid concentration in cooking vinegar samples. Results achieved were not significantly different from those obtained following a batchwise standard aoac titration method
A green sequential injection spectrophotometric method employing natural reagent extracts was successfully developed for analysis of acetic acid. Crude turmeric and lime extracts can replace toxic chemical reagents for the quantification of acetic acid content in cooking vinegar samples. The proposed system significantly increased the performance of acid-base titration for acetic acid assay as a simple, cost-effective method with a high degree of automation and low chemical consumption. The proposed system was reproducible, accurate, and rapid with a sample throughput rate of 45 injections h−1. Satisfactory recovery and high sample measurement frequency proved that the proposed system has high potential as an alternative method for quality control of acetic acid content in vinegar products.
