Validated stability indicating methods for determination of nitazoxanide in presence of its degradation products

AbstractThree sensitive, selective and reproducible stability-indicating methods are presented for determination of nitazoxanide (NTZ), a new anti-protozoal drug, in presence of its degradation products. Method A utilizes the first derivative of ratio spectra spectrophotometry by measurement of the amplitude at 364.4nm using one of the degradation products as a divisor. Method B is a chemometric-assisted spectrophotometry, where principal component regression (PCR) and partial least squares (PLS) were applied. These two approaches were successfully applied to quantify NTZ in presence of degradation products using the information included in the absorption spectra in the range 260–360nm. Method C is based on the separation of NTZ from its degradation products followed by densitometric measurement of the bands at 254nm. The separation was carried out on silica gel 60F254, using chloroform–methanol–ammonia solution–glacial acetic acid (95:5:1:1 by volume, pH=5.80) as a developing system. These methods are suitable as stability-indicating methods for the determination of NTZ in presence of its degradation products either in bulk powder or in pharmaceutical formulations. Statistical analysis of the results has been carried out revealing high accuracy and good precision

Validated determination of diacerein and its active metabolite, rhein, by stability indicating constant pattern method as a novel manipulation of zero order spectra

A novel spectrophotometric method named constant absorbance pattern technique was proposed for simple determination of binary mixtures exemplified by diacerein, a treatment of osteoarthritis, and rhein, diacerein main alkaline degradation product and active metabolite. The proposed novel constant absorbance pattern technique was highly accurate, precise, sensitive, specific and stability indicating as well. The proposed technique allowed determination of diacerein and rhein in their binary mixtures manipulating zero order absorption spectra with no need for ratio spectra, derivatization steps, or even preliminary separation. Diacerein was determined at zero absorption spectra depending on the constant absorbance pattern between the two wavelengths 230 and 430 nm while rhein was directly determined at zero order at its λmax, 430 nm. The proposed methods showed obeying for Beer-Lambert’s law in the concentration range of 1–16 µg mL−1 for both diacerein and rhein. Validation of the proposed methods was carried out according to ICH guidelines with respect to accuracy and precision. Moreover, the proposed method was applied for determination of Diacerein in different pharmaceutical formulations and results were statistically compared with those of the reported HPLC one where no significant difference was found concerning Student’s t-test and F-value

Validated spectrophotometric and spectrodensitometric methods for determination of a ternary mixture of analgesic drugs in different dosage forms

Accurate, sensitive and precise methods have been developed for determination of aspirin, caffeine, and paracetamol, in their ternary mixture with minimum sample pretreatment and without previous separation. Method (A) is a spectrophotometric one that depends on determination of aspirin and paracetamol using the successive derivative of the ratio spectra and measuring the amplitudes at 241.2 and 228.2 nm, respectively. Caffeine is indirectly determined using a calculated equation by measuring the amplitude of the third derivative spectra at 285.6 at which there is no interference from paracetamol and interference from aspirin was removed by subtraction as aspirin was selectively determined at 241.2 nm, where CAF showed no absorbance. Method (B) depends on quantitative TLC-Densitometric separation of the ternary mixture using silica gel 60 F254 plates and scanning at 230 nm using chloroform:methanol:acetic acid:ammonia solution (95:5:0.5:0.2, by volume) as a developing system. The proposed methods have been validated as per ICH guidelines and USP requirements. Moreover the developed methods have been applied for determination of the above mentioned drugs in different pharmaceutical formulations where no interference from the excipients has been detected. Statistical comparison of the results obtained from the suggested methods with those of the reported HPLC method showed no significant difference. The developed methods can be considered sensitive, accurate, and cost-effective methods

Applying novel economic simple green sample preparation procedures on natural and industrial specimens for chromatographic determination of insecticidal residues

Abstract Spraying a tertiary blend of the insecticides (hexythiazox, imidacloprid, and thiamethoxam), on tomato fruits, is a routine in agriculture-attentive countries. A simple green sample preparation technique was developed and applied to the field samples. Specific HP-TLC and RP-HPLC methodologies are established to estimate the residual insecticides and applied to the prepared field specimens. In the planner chromatographic methodology, methanol:chloroform:glacial acetic acid:triethyl amine (8.5:1.5:0.2:0.1, v/v) is recommended as a mobile system. The other one is columnar chromatography; acetonitrile: water (20:80, v/v), pH 2.8, is recommended as a mobile system. The validation parameters were examined following the ICH rules. The means percentages and standard deviations of the accuracy of the HP-TLC method for the determined compounds were 99.66 ± 0.974, 99.41 ± 0.950, and 99.89 ± 0.983, correspondingly. The values were 99.24 ± 0.921, 99.69 ± 0.681, and 99.20 ± 0.692, correspondingly, when they were determined by the RP-HPLC method. The relative standard deviation percentages of the methods’ repeatability and intermediate precision ranged from 0.389 to 0.920. Both methods were highly specific having resolution factors of ≥ 1.78 and selectivity factors of ≥ 1.71. They were applied to the field samples perfectly