No abstract

Three simple methods are described for the determination of amoxicillin (AMX) in bulk drug and dosage forms using iodate-iodide mixture reagent. These methods employed the well-known analytical reaction between iodate-iodide mixture in the presence of acid solution. The iodide oxidized by iodate to iodine in an amount equivalent to the-COOH group present in amoxicillin (AMX) and the liberated iodine determined by titrimetry and spectrophotometry. In the titrimetric method (method A), the liberated iodine was reacted with a measured excess of thiosulphate and the residual thiosulphate was determined by titration with a standard iodine solution using starch indicator, the method was applicable over 2-16 mg of AMX. In the second and third methods, the absorbance of the liberated iodine was measured at 370 nm (method B) and also iodine was reacted with starch and starch-iodine complex was measured at 570 nm (method C). In spectrophotometric methods (B and C), Beer's law was obeyed over the concentration range of 5-50 and 5-60 µg mL-1 AMX with a molar absorptivity values of 5.55×10 3 L mol-1 cm-1 and 4.76×10 3 L mol-1 cm-1 for the method A and method B, respectively. The limits of detection (LOD) and quantification (LOQ) were calculated for method B and method C. The proposed methods were found to yield reliable results when applied to bulk drug and dosage forms analysis, and hence they can be applied in quality control laboratories.

The importance of pharmaceuticals comes from their direct connection to human life. Therefore, many analysis techniques such as chromatography, spectroscopic methods, and others have been developed for one goal, which is to ensure that the drug reaches humans with high quality. Spectrophotometric and titrimetric methods have been in general use for the last 40 years and over this period have become the most important analytical instrument in the modern-day laboratory. In many applications, other techniques could be employed in pharmaceutical analysis, but none rival UV–visible spectrometry as well as titrimetry, for their simplicity, versatility, speed, accuracy, and cost-effectiveness. This chapter highlights the spectroscopic methods in the ultraviolet and visible regions, as well as the titration methods that are still widely used in the field of pharmaceutical analysis. The types of titrations, as well as the most important reactions used in spectrophotometric methods, are presented. Examples of the most important applications in the field of pharmaceutical analysis are also presented.

An inexpensive, accurate, and simple green spectrophotometric assay was developed and validated for the determination of the antibiotic drug, Amoxicillin (AMX), in pure drug and tablet using ninhydrin (NIH). The method relied on the condensation reaction between the drug and Ninhydrin reagent (NIH) in the present NaHCO3, and then the colored product was measured at 420 nm. The absorbance measured was related to AMX concentration. Different experimental conditions of assay were studied, and optimized. Beer’s law for the method is obeyed over the concentration ranges 30-180 µg mL-1. The molar absorptivity value was 1.76×103 L mol-1 cm1. The limits detection (LOD) and quantification (LOQ) values were 0.9 and 2.73 mg mL-1. The method was validated according to ICH guidelines for precision and accuracy, robustness and ruggedness, and selectivity. The intraday and inter-day relative standard deviation (%RSD) values for precisions were found to be in the range of 1.53–2.62%, whereas the respective relative error (%RE) values for accuracy were better than 2.25%. Robustness and ruggedness were tested, and the %RSD values were within the accepted limits in both instances. Also, placebo blank and synthetic mixture analysis was applied for method selectivity. The results showed that there is no interference resulting from co-formulated materials in the developed method. The assay was successfully applied for the determination of AMX in commercial tablets and capsules with reliable, satisfactory results, and indicated that the proposed method was as accurate and precise as the official methods. Hence, the proposed method can be applied in pharmaceutical laboratories of quality control.