A simple, accurate, precise and sensitive HPLC method with UV detection was developed and validated to estimate Stavudine in human extracted from human plasma using methanol, by using protein precipitation method. It was chromatographed on a Phenomenex Luna C 50μL injection volume and UV detector. An isocratic mobile phase consisting of a mixture of ortho phosp horic acid buffer used in the analysis. The retention time (R t) The method was valida ted over the range of 0.025μg/mL to 1.750 µg/mL The intra and inter -day precision (%RSD.) values of concentrations ranged from 1.369% to 4.166%. The maximum recovery was achieved at medium and high quality control samples and was 98.40%. The described method can be readily utilized for evaluation of clinical data of Stavudine in human

Performance liquid chromatography method for determination of stavudine in human plasma

Two
simple, rapid, sensitive, accurate, precise and economical Visible
Spectrophotometric methods have been developed for the determination of
Etravirine in pure and pharmaceutical formulations. These methods (A and B)
were based on nucleophilic substitution and oxidative coupling reactions of
Etravirine by 1,2-naphtha
quinone-4-sulphonate (NQS) in alkaline medium and 3-methyl-2-benzothiazolinone
hydrazone (MBTH) in acidic medium with the maximum absorbance at 414 nm and 635 nm respectively. Linearity was obtained in the
concentration range of 5 -30 μg/ml and
2 -10 μg/ml which was corroborated by the correlation
coefficient (r) values of 0.9995 and 0.9996 respectively. The methods developed
were validated with respect to linearity, accuracy (recovery), precision,
Sandell’s sensitivity, molar extinction coefficient and specificity. The
proposed methods are successfully applied for the determination of Etravirine
in bulk and pharmaceutical formulations and results were validated
statistically by recovery studies.

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Spectrophotometric Determination of Etravirine in Bulk and Pharmaceutical Formulations

A potentiometric sensor based on carbon paste electrode impregnated concurrently with molecularly imprinted polymer (MIP) and multi-walled carbon nanotubes (MWCNTs) was fabricated and used to measure stavudine (STV), currently applied as a drug in the treatment of human immuno-deficiency virus (HIV) infection. To synthesize the MIP, methacrylic acid (or acryl amide) and ethylene glycol dimethacrylate were utilized as functional monomer and cross-linker, respectively. The kind of the functional monomer had decisive influence on the response of the MIP-based electrode to target molecule of STV. MWCNTs had positive effect on both sensitivity and detection range of the electrode. The electrode response behavior (Nernstian behavior) was shown to be affected by homoconjugation of STV molecules in the imprinting process. The proposed sensor exhibited Nernstian slope of 27.9 mV per decade for stavudine over a wide concentration range of 1.0 × 10−6 to 1.0 × 10−1 mol L−1, with a detection limit of 5.0 × 10−7 mol L−1. The sensor was used for STV determination in pharmaceutical samples.

A carbon nanotubes/graphite paste electrode impregnated with stavudine-imprinted polymer as a stavudine selective sensor

Objective: The aim of this paper was to develop the spectrophotometric method of an antimalarial drug chloroquine in bulk and pharmaceutical formulations. Methods: A simple, sensitive and accurate spectrophotometric method have been developed for the determination of chloroquine in pure and dosage forms which is based on oxidation of the drug with Fe(III)-1, 10 phenanthroline complex producing orange colored chromogen which is measured at 510 nm. Different experimental parameters affecting the color development and stability of the colored product are carefully studied and optimized. Results: Beer’s law is obeyed in the concentration range of 20-320 µg/ml for the developed method. The molar absorptivity and sandell sensitivity are found to be 666.66 L mol -1 cm -1 and 0.77 µg/cm 2 respectively. The regression equation for chloroquine was found to be y = 0.0013X+0.005 and the correlation coefficient for the regression line were 0.999. Conclusion: The developed method could be successfully applied for determination of chloroquine in pharmaceutical formulations. The results obtained are in good agreement with those obtained by using the standard method. Keywords : Chloroquine, Spectrophotometry, Dosage forms, 1, 10-phenanthroline (O-PHEN), Fe (III).

Spectrophotometric determination of an antimalarial drug chloroquine in bulk and pharmaceutical formulations

Objective: Two simple and sensitive Spectrophotometric methods are developed for estimation of Mephedrone. Methods: The first method is based on oxidation of the drug with alkaline Potassium Permanganate at room temperature (25± °c). The increase in absorbance of colored Manganate ions was measured at 610 nm. The second method is based on the oxidation of the drug with 1, 10–phenanthroline producing red colored chromogen which is measured at 510 nm. Results: All parameters affecting the developments of the color were investigated and the conditions were optimized. Under the optimum condition used, Beer’s law was obeyed in the concentration range 40-160 µg/ml and 80-220 µg/ml for method A and B respectively. Molar absorptivity was found to be 4.60×10 2 L. mole -1 cm -1 and 3.89×10 2 L. mole -1 cm - 1 respectively. Conclusion: The proposed methods are well suited for determination of Mephedrone in bulk samples. Keywords: Mephedrone, Spectophotomerty, Oxidation, Potassium permanganate, 1, 10-phenanthroline.

Spectrophotometric determination of mephedrone in a bulk form

Two simple, sensitive and accurate spectrophotometric methods have been developed for the determination of stavudine in pure and dosage forms. Method-A is based on the reaction of stavudine(STD) with 1,2-napthaquinone4-sulphonic acid (NQS) to form N-alkylamono naphthaquinone by replacement of the sulphonate group of the naphthaquinone sulphonic acid by an amino group. The colored chromogen shows absorption maximum at 464 nm and linear within the limits 2.0-12.0 µg/mL. Method-B is based on oxidation of the drug with 1, 10-phenanthroline producing red colored chromogen which is measured at 480nm. Beer’s law is obeyed in the concentration range of 5.0-30.0 µg/mL for the developed method. Different experimental parameters affecting the color development and stability of colored product are carefully studied and optimized. The developed methods could be successfully applied to pharmaceutical formulations. The results obtained are in good agreement with those obtained using official methods.

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M. R. Appa

Papers

Spectrophotometric determination of an antiretroviral drug stavudine in bulk and pharmaceutical formulations