scholarly journals Spectrophotometric determination of diclofenac in pharmaceutical preparations assisted by microwave oven

2005 ◽  
Vol 30 (1) ◽  
pp. 29-36 ◽  
Author(s):  
E. G. Ciapina ◽  
A. O. Santini ◽  
P. L. Weinert ◽  
M. A. Gotardo ◽  
H. R. Pezza ◽  
...  

In this work, an effective and low-cost method for the determination of sodium or potassium diclofenac is proposed in its pure form and in their pharmaceutical preparations. The method is based on the reaction between diclofenac and tetrachloro-p-benzoquinone (p-chloranil), in methanol medium. This reaction was accelerated by irradiating of reactional mixture with microwave energy (1100 W) during 27 seconds, producing a charge transfer complex with a maximum absorption at 535 nm. The optimal reaction conditions values such as reagent concentration, heating time and stability of the reaction product were determined. Beer's law is obeyed in a concentration range from of 1.25x10-4 to 2.00x10-3 mol l-1 with a correlation coefficient of 0.9993 and molar absorptivity of 0.49 x10³ l mol-1 cm-1. The limit of detection (LOD) was 1.35x10-5 mol l-1 and the limit of quantification (LOQ) was 4.49x10-5 mol l-1. In the presence of the common excipients, such as glucose, lactose, talc, starch, magnesium stearate, sodium sulphite, titanium dioxide, polyethyleneglycol, polyvinylpirrolidone, mannitol and benzilic alcohol no interferences were observed. The analytical results obtained by applying the proposed method compare very favorably with those given by the United States Pharmacopeia standard procedure. Recoveries of diclofenac from various pharmaceutical preparations were within 95.9% to 103.3%, with standard deviations ranging from 0.2% to 1.8%.

2003 ◽  
Vol 28 (1) ◽  
pp. 39-44 ◽  
Author(s):  
P. R. da S. Ribeiro ◽  
A. O. Santini ◽  
H. R. Pezza ◽  
L. Pezza

A simple, precise, rapid and low-cost potentiometric method for captopril determination in pure form and in pharmaceutical preparations is proposed. Captopril present in tablets containing known quantity of drug was potentiometrically titrated in aqueous solution with NaOH using a glass pH electrode, coupled to an autotitrator. No interferences were observed in the presence of common components of the tablets as lactose, microcrystalline cellulose, croscarmellose sodium, starch and magnesium stearate. The analytical results obtained by applying the proposed method compared very favorably with those obtained by the United States Pharmacopoeia Standard procedure. Recovery of captopril from various tablet dosage formulations range from 98.0 to 102.0%.


2019 ◽  
Vol 10 (2) ◽  
pp. 1367-1371
Author(s):  
Khalaf F Al Samarrai ◽  
Eman Thiab A Al Samarrai ◽  
Baidaa Adnan Al Samarrai

A simple, rapid and low-cost spectrophotometric method for determination of Methyldopa (MDA) based on ion-pair formation using Bromothymol blue (BTB) as a reagent in alkaline medium (pH 8.7). The absorbance of the green-blue-coloured product is measured at 616 nm. Beer's Law is obeyed at concentration range up to 5-20μg/ml with molar absorptivity 0.8279x104 L/mol.cm. The correlation coefficient, limit of detection and limit of quantification were 0.9982, 0.4318 μg/ml and 1.4393 μg/ml respectively. The method has been successfully applied to the determination of Methyldopa in pharmaceutical preparations.


2019 ◽  
Vol 31 (1) ◽  
pp. 1-9
Author(s):  
Deepak Kumar Sahu ◽  
Joyce Rai ◽  
Chhaya Bhatt ◽  
Manish K. Rai ◽  
Jyoti Goswami ◽  
...  

In modern age pesticide is used widely in agriculture. Lambda-cyhalothrin (LCT) is one of the most used pesticides which are used as a insecticide to kill pest, tricks, flies etc in agricultural field and it is also used for crop production. We have developed new method to detect LCT insecticide in agriculture field and reduce its uses. In this method we found the maximum absorbance at 460 nm for yellow colour dye. We also calculated limit of detection and limit of quantification 0.001 mg kg-1 and 0.056 mg kg-1 respectively. Molar absorptivity and Sandell’s sensitivity was also calculated and obtained 1.782 ×107 mol-1 cm-1 and 9.996 ×10-6 µg cm-2 respectively. The obtained yellow colour dye obeyed Beer’s law limit range of 0.5 µg ml -1 to 16 µg ml-1 in 25 ml. This method is less time consuming, selective, simple, sensitive and low cost. Present method is successfully applied in various soil, water and vegetable samples.


2020 ◽  
Vol 32 (6) ◽  
pp. 1314-1320
Author(s):  
Lamya A. Sarsam ◽  
Salim A. Mohammed ◽  
Sahar A. Fathe

A rapid, simple and sensitive spectrophotometric and RP-HPLC methods have been developed for the quantitative determination of cefotaxime-Na in both pure and dosage forms. The spectrophotometric method was based on diazotization of cefotaxime-Na and then coupling with 8-hydroxyquinoline in an alkaline medium. The resulting azo dye exhibited maximum absorption at 551 nm with a molar absorptivity of 0.597 × 104 L mol-1 cm-1. Beer′s law was obeyed over the range 10-700 μg/25 mL (i.e. 0.4-28.0 ppm) with an excellent determination coefficient (R2 = 0.9993). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.0194 and 0.3765 μg mL-1, respectively. The recoveries were obtained in the range 97.3-102.5% and the relative standard deviation (RSD) was better than ± 1.56. The HPLC method has been developed for the determination of cefotaxime-Na. The analysis were carried out on a C18 column and a mobile phase composed of acetonitrile and phosphate buffer solution (0.024M KH2PO4 and 0.01M H3PO4) at pH 3.5 in the ratio of 60:40 (v:v), with a flow rate of 1.0 mL min-1 and UV detection at 258 nm. The proposed method showed good linearity (in a range of concentration 1.0-200 μg mL-1. The recovery percent and a relative standard deviations were found in the range 96 to 104.8% and ± 0.017 to ± 0.031%, respectively. Both methods were applied successfully to the assay of cefotaxime-Na in commercial injection preparations.


2016 ◽  
Vol 11 (2) ◽  
pp. 3540-3551
Author(s):  
Taghreed A. Mohammed ◽  
Mona A. Mohamed

A selective and new spectrophotometric method is described for determination of three antiepileptic drugs; namely lamotrigine (LAM), gabapentin (GAB), and oxcarbazepine (OXC) in drug substances and in drug products using vanillin reagent as the chromogenic agent. The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the yellow colored products were measured at 405, 396, and 400 nm respectively. Beer’s law was obeyed at (0.4 – 10), (0.1-10), and (0.5-11) μg/mL, and  the calculated molar absorptivity values are 2.52 x 104, 1.74 x 104, and 2.54 x 104 L/mol/cm for LAM, GAB, and OXC respectively. Sandell sensitivity, the limit of detection (LOD) and limit of quantification (LOQ) were calculated. No interference was observed from common additives found in drug products. The presented method was validated according to ICH guidelines. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level, and there was no significant difference between the reference and proposed method with regard to accuracy and precision. The method offers the advantages of rapidity, simplicity and sensitivity and low cost and can be easily applied to resource poor settings without the need for expensive instrumentation and reagents.


2020 ◽  
Vol 11 (4) ◽  
pp. 291-297
Author(s):  
Hutaf Mustafa Baker ◽  
Hussam Ahmad Alsaoud ◽  
Hamzeh Mohamad Abdel-Halim

A simple, sensitive and reproducible method for the determination of ranitidine hydrochloride in pharmaceutical preparations was investigated. This spectrophotometric method was based on the formation of a deep red color product with ninhydrin in basic media and the absorbance measured at λmax = 480 nm. The reaction occurs at 45 °C with pH = 10 having a contact time of 38 minutes. Under the optimum conditions, Beer’s Law is obeyed in the concentration range of 8.98×103 - 9.90×104 µg/L. The coefficient of correlation was found to be 0.999 for the obtained method with molar absorptivity of 3.05×103 L/mol.cm. The calculated Sandell’s sensitivity is 0.108 μg/cm2. The limit of detection and limit of quantification are 0.0997 and 0.3023 µg/mL, respectively. The low values of the percentage relative standard deviation and percentage relative error indicate the high precision and the good accuracy of the proposed method. The stoichiometry of the reaction is determined and found to be 1:4 (Ranitidine hydrochloride:Ninhydrin). The initial rate method confirmed that this reaction is first order one.


2019 ◽  
Vol 13 (1) ◽  
pp. 52-57
Author(s):  
Rawa M. Tagi ◽  
Raad J. Al-Timimi ◽  
Muna M. Hassan ◽  
Mohammed J. Hamzah

Background: The research is involved development a new spectrophotometric method based on the oxidative coupling reactions for determination of important phenothiazine drug which is promethazine HCl in pure solutions and local pharmaceutical preparations. Materials and methods: The Standard promethazine HCl was treated with organic reagent of P-Chloroaniline as a coupling reagent in the presence of oxidizing agent Ammonium Cerric (IV) Sulphate, the reaction leads to the formation a blue –greenish color product that has a maximum absorption at 603nm. Results: The variables of reaction conditions including optimum volumes of both reagent and oxidizing agent, acidity of the reaction medium, order of addition and stability time were studied. The obtained results of the purposed method shows that a Beer law is obeyed in the range of 7-40ppm with a correlation coefficient (r2) of 0.9981. While the molar absorptivity (ξ) of 1.861x103 L.mol-1.cm-1, sandal sensitivity(s) of 0.172μg.cm-2, limit of detection (LOD) of 4.02ppm and limit of quantification (LOQ) of 13.39ppm were obtained. The developed method was compared with the standard method adopted by USP using F and t-tests and the results shows no significant deferent between both methods. Conclusion: The analytical method was also applied successfully for pharmaceutical preparations containing promethazine HCl.


Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.


2007 ◽  
Vol 4 (2) ◽  
pp. 173-179 ◽  
Author(s):  
K. Basavaiah ◽  
U. R. Anil Kumar

A simple spectrophotometric method is proposed for the determination of zidovudine(ZDV) in bulk drug and in pharmaceutical preparations. The method is based on the oxidation of ZDV by a known excess of oxidant N-bromosuccinimide (NBS), in buffer medium of pH 1.5, followed by the estimation of unreacted amount of oxidant with metol and sulphanilic acid. The reacted oxidant corresponds to the amount ZDV. The purple-red reaction product absorbs maximally at 530 nm and Beer’s law is obeyed over a range 5 to 75 μg mL-1. The apparent molar absorptivity is calculated to be 5.1×103L mol-1cm-1, and the corresponding Sandell sensitivity value is 0.052 μg cm-2. The limit of detection and quantification are found to be 0.90 and 2.72, respectively. Intra-day and inter-day precision and accuracy of the developed methods were evaluated as per the current ICH guidelines. The method was successfully applied to the assay of ZDV in tablet/capsule preparations and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common tablet/capsule excipients. The accuracy of the method was further ascertained by performing recovery studies via standard-addition method.


2015 ◽  
Vol 12 (1) ◽  
pp. 167-177 ◽  
Author(s):  
Baghdad Science Journal

A spectrophotometric method has been proposed for the determination of two drugs containing phenol group [phenylephrine hydrochloride (PHP) and salbutamol sulphate (SLB)] in pharmaceutical dosage forms. The method is based on the diazotization reaction of metoclopramide hydrochloride (MCP) and coupling of the diazotized reagent with drugs in alkaline medium to give intense orange colored product (?max at 470 nm for each of PHP and SLB). Variable parameters such as temperature, reaction time and concentration of the reactants have been analyzed and optimized. Under the proposed optimum condition, Beer’s law was obeyed in the concentration range of 1-32 and 1-14 ?g mL-1 for PHP and SLB, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for each of PHP and SLB were 0.60, 0.52 ?g mL-1 and 2.02, 1.72 ?g mL-1, respectively. No interference was observed from common excipients present in pharmaceutical preparations. The good correlation coefficients and low relative standard deviation assert the applicability of this method. The suggested method was further applied for the determinations of drugs in commercial pharmaceutical preparations, which was compared statistically with reference methods by means of t- test and F- test and were found not to differ significantly at 95% confidence level. The procedure was characterized by its simplicity with accuracy and precision.


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