Colorimetric Determination of Acetylenic Hypnotics by Formation of Silver Acetylides

1980 ◽  
Vol 63 (1) ◽  
pp. 88-90
Author(s):  
Mohamed S Rizk ◽  
Mohamed I Walash ◽  
Amina El-Brashy

Abstract A colorimetric method is described for the determination of certain mono-substituted acetylenic hypnotic drugs—ethinamate, methyl pentynol carbamate, and ethchlorvynol. Silver acetylide is formed and extracted into isobutyl methyl ketone. After acidification, an equivalent amount of silver ions is liberated which is assayed colorimetrically as silver dithizonate (λ max. 472 nm). About 10–50 μg compound could be assayed with good accuracy. The procedure is reproducible and precise (standard deviation 1.5–2.19%). The procedure was successfully applied to different pharmaceutical dosage forms.

1987 ◽  
Vol 70 (3) ◽  
pp. 568-571 ◽  
Author(s):  
Mohamed E El-Sadek ◽  
Hisham E Abdel Latef ◽  
Afaf A Aboul Khier

Abstract A colorimetric method is proposed for determination of terbutaline sulfate, orciprenaline sulfate, and their dosage forms. The suggested method depends on nitrosation of the 2 drugs by using sodium nitrite and hydrochloric acid. Addition of sodium hydroxide increases the intensity of the color developed. The difference between absorption values measured in acid and alkaline media is taken as a measure of concentration. Variables were carefully studied and optimized. Results for both compounds adhered to Beer's law over the range 2- 28 μg/mL. The method has proved to be accurate and precise for analysis of pharmaceutical dosage forms.


2002 ◽  
Vol 35 (2) ◽  
pp. 183-197 ◽  
Author(s):  
Mohamed H. Abdel-Hay ◽  
Amal Saleh ◽  
E. S. H. El Ashry ◽  
N. Rashed ◽  
Osama Salama

Author(s):  
Zeinab Adel Nasr ◽  
Noha S. Said ◽  
Sawsan A. Abdel-Razeq

Aims: Two spectrophotometric methods were developed and validated for the determination of sofosbuvir in presence of its alkaline degradate. Study Design: Ratio difference and ratio derivative methods were assisted for determination of sofosbuvir in presence of its alkaline degradate, laboratory-prepared mixtures and in tablet dosage forms. Place and Duration of Study: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy (Girls), Al - Azhar University, between December 2019 and January 2020. Methodology: Two analytical methods were achieved and validated for the quantitative determination of Sofosbuvir in presence of its alkaline degradate. The first method was ratio difference (RD) method, where the UV absorption spectra of different concentrations of sofosbuvir were divided by the spectrum of a certain concentration (15 µg mL-1) as a devisor of its alkaline degradate to get the ratio difference spectra. Afterwards, the peak amplitudes difference between 253.7 and 243.5 nm were measured. The second method was the ratio derivative (1DR) method, where the first derivative of the ratio spectra (1DR) was obtained and its amplitude was measured at 247 and 268 nm. Good linearity was obtained over the concentration range of 3-15 µg mL-1 for the proposed methods. The proposed procedures were adopted for the selective determination of intact Sofosbuvir in presence of up to 80% of its degradation product. Sofosbuvir was exposed to different conditions as alkaline, acidic and oxidative degradation. Results: The proposed methods were developed and validated with good linearity range of 3-15 µg mL-1 for both methods, and also with good accuracy and precision. And the obtained results were statistically compared to those obtained by the reported method. Conclusion: Sofosbuvir was successfully determined by the proposed ratio difference and ratio derivative methods in bulk powder, laboratory prepared mixtures and tablet dosage form with good accuracy and precision. The methods were validated according to ICH guidelines. The results obtained were compared with those of the reported method and were found to be in good agreement.


1986 ◽  
Vol 69 (3) ◽  
pp. 513-518 ◽  
Author(s):  
Adel F Youssef ◽  
Salwa R El-Shabouri ◽  
Fardous A Mohamed ◽  
Abdel Maboud I Rageh

Abstract A colorimetric method was developed for the quantitative estimation of 11 phenothiazine drugs. The method is based on the interaction of unsulfoxidized drug with morpholine and iodine-potassium iodide reagents. The interaction for all studied phenothiazine drugs yields a blue product with 2 absorption maxima: one in the range of 620-640 nm with lower molar absorptivity and the other in the range of 662-690 nm with higher molar absorptivity. The color was stable for at least 10 h. The reproducibility and recovery of the method were excellent. The method was applied successfully to the analysis of various commercially available phenothiazines in different dosage forms. The results were comparable to those obtained by official procedures. The suitability of the method for detection and estimation of promethazine excreted in urine has been suggested by preliminary experiments. Reaction products have been isolated and identified.


1982 ◽  
Vol 65 (1) ◽  
pp. 138-140
Author(s):  
Mohamed S Rizk ◽  
Mohamed I Walash ◽  
Amina El-Brashy

Abstract An ion selective electrode has been used for indirect titrimetric assay of ethchlorvynol, ethinamate, and meparfynol carbamate. These acetylenic hypnotics form silver acetylide in the presence of excess silver. Excess silver is determined potentiometrically with standardized iodide solution and an iodide selective electrode. With this technique, 0.10-20 mg drug was determined with 95.7 ± 1.3-110.8 ± 5.9% accuracy. The procedure has been successfully applied to different pharmaceutical dosage forms.


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Swathi Naraparaju ◽  
Durai Ananda Kumar Thirumoorthy ◽  
Sunitha Gurrala ◽  
Asra Jabeen ◽  
Pani Kumar D. Anumolu

Abstract Background A simple and sensitive spectrophotometric method was developed for the quantitative measurement of dolutegravir in pure form and pharmaceutical formulation. The present method was based on redox reaction between dolutegravir and ferric chloride, which upon complexation with 1,10-phenanthroline formed an orange-colored complex that showed absorption maximum at 520.0 nm. Results The developed method obeyed linearity in the concentration range of 40.00–140.00 μg/mL. The method was also validated as per International Council for Harmonization guidelines and the results were within acceptance values. The validated method was employed for the determination of dolutegravir in pharmaceutical dosage form and the percentage assay value was found to be 102.5, which is in agreement with its label claimed. Conclusion The developed redox-based colorimetric method could be used in the routine quality control analysis of dolutegravir present in various pharmaceutical dosage forms.


Author(s):  
Rajan V. Rele ◽  
Prathamesh P. Tiwatane

Simple sensitive and accurate extractive colorimetric method was developed for the estimation of favipiravir in Pharmaceutical dosage forms. The method was based on the formation of colored ion pair complexes by the drugs with thiocynate ions. These ion pair complexes were quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 618 respectively. The proposed method was validated statistically. A recovery of method was carried out by standard addition methods. The Beer’s law ranges were found to be 1-12μg/ml, respectively. The low values of standard deviation and percentage RSD indicate high precision of method. Hence the method is useful for routine estimation of favipiravir in tablets respectively.


1972 ◽  
Vol 55 (1) ◽  
pp. 155-160
Author(s):  
William M Plank

Abstract A method has been investigated for the determination of bismuth in pharmaceutical dosage forms by conventional dc polarography. The method is applicable to tablets, emulsions, suspensions, injectables, and bulk powders. A collaborative study has shown the method to be superior in accuracy and precision to the present official colorimetric method, 36.300- 36.304. The results from 16 determinations performed by 8 collaborators were: 100.0±1.5% recovery on a synthetic powder mix, a relative standard deviation of 1.9% on a commercial tablet sample, and a relative standard deviation of 2.1% on a magma sample. By comparison, the collaborative data reported for the present official method gave relative standard deviations of 3.4 and 3.2% on 2 samples of powder mixtures. It is recommended that the polarographic method be adopted as official first action.


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