ABSTRACT
A simple and accurate stability-indicating thin-layer chromatographic (TLC) method is developed and validated for the quantitative determination of ribavirin (RBV) in its bulk and with used for development consists of chloroform-methanol-acetic acid (60:15:15, v/v/v). The separated spots are visualized as bluish green spots after being sprayed with anisaldehyde reagent. RBV is subjected to different accelerated stress conditions. The drug is found to undergo degradation under all stress conditions, and the degradation products are well resolved from the pure drug with significantly different Rf values. The optical densities of the separated spots are found to be linear with the amount of RBV in the range of 5-40 microg/spot with a good correlation coefficient (r=0.9980). The limit of detection and limit of quantitation values are 1.40 and 4.67 microg/spot, respectively. Statistical analysis proves that the method is repeatable and accurate for the determination of RBV in the presence of its degradation products. The method meets the International Conference on Harmonisation/Food and Drug Administration regulatory requirements. The proposed TLC method is successfully applied for the determination of RBV, pure and in capsules, with good accuracy and precision; the label claim percentages are 98.8%+/-1.5%. The results obtained by the proposed TLC method are comparable with those obtained by the official method.
Subject(s)
Chromatography, Thin Layer/methods , Ribavirin/analysis , Drug Stability , Molecular Structure , Reproducibility of Results , Ribavirin/chemistryABSTRACT
A simple and accurate thin-layer chromatographic (TLC) method for quantitative determination of amantadine hydrochloride (AMD) was developed and validated. The method employed TLC aluminum plates pre-coated with silica gel 60F-254 as a stationary phase. The solvent system used for development consisted of n-hexane-methanol-diethylamine (80: 40: 5, v/v/v). The separated spots were visualized as brown spots after spraying with modified Dragendorff's reagent solution. Amantadine hydrochloride was subjected to accelerated stress conditions: boiling, acid and alkaline hydrolysis, oxidation, and irradiation with ultraviolet light. The drug was found to be stable under all the investigated stress conditions. The method was validated for linearity, limits of detection (LOD) and quantitation (LOQ), precision, robustness, selectivity and accuracy. The optical densities of the separated spots were found to be linear with the amount of AMD in the range of 5-40 µg/spot with good correlation coefficient (r=0.9994). The LOD and LOQ values were 0.72 and 2.38 µg/spot, respectively. Statistical analysis proved that the method is repeatable and accurate for the determination of AMD. The method, in terms of its sensitivity, accuracy, precision, and robustness met the International Conference of Harmonization/Federal Drug Administration regulatory requirements. The proposed TLC method was successfully applied for the determination of AMD in bulk and capsules with good accuracy and precision; the label claim percentages were 99.0 ± 1.0%. The results obtained by the proposed TLC method were comparable with those obtained by the official method. The proposed method is more advantageous than the previously published chromatographic methods as it involved the most simple chromatographic technique; TLC. In addition, method relies on the use of inexpensive equipment, a scanner and software, and not critical derivatizing reagent, thus maximizing the ability of laboratories worldwide to analyze samples of AMD.
ABSTRACT
A simple and sensitive fluorimetric method for determination of antiviral drugs: ribavirin, acyclovir, and amantadine hydrochloride has been developed. The method was based on the oxidation of these drugs by cerium(IV) in presence of perchloric acid and subsequent monitoring the fluorescence of the induced cerium(III) at lambdaexcitation 255 and lambdaemission 355 nm. Different variables affecting the reaction conditions such as the concentrations of cerium(IV), type and concentration of acid medium, reaction time, temperature, and the diluting solvents were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9978-0.9996) were found between the relative fluorescence intensity and the concentrations of the investigated drugs in the range of 50-1400 ng ml-1. The assay limits of detection and quantitation were 20-49, and 62-160 ng ml-1, respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 1.58%. No interference could be observed from the excipients commonly present in dosage forms. The proposed method was successfully applied to the analysis of the investigated drugs in pure and pharmaceutical dosage forms with good accuracy and precision; the recovery percentages ranged from 99.2 to 101.2+/-0.48-1.30%. The results obtained by the proposed fluorimetric method were comparable with those obtained by the official method stated in the United States Pharmacopoeia.
