Green Validated TLC and UV Spectrometric Techniques for Hyoscine Butylbromide and Ketoprofen Determination in Pharmaceutical Dosage Form

Journal of Analytical Chemistry - Two spectrometric methods and a TLC-densitometric method are described for the determination of hyoscine/ketoprofen combination. A new spectrophotometric method...     

Selective potentiometric determination of zolpidem hemitartrate in tablets and biological fluids by using polymeric membrane electrodes

The construction and electrochemical response characteristics of 4 polymeric membrane sensors were investigated for potentiometric determination of zolpidem hemitartrate. The construction of the 4 sensors was based on the formation of ion-pair complexes between the drug cation and ionic sites in the ratio of 1:2, respectively. Two of the sensors were constructed by using ammonium reineckate or ammonium tungstate as the fixed ionic site in a polymeric matrix of polyvinyl chloride (PVC) (sensors 1 and 2). Linear responses over the concentration range of 10(-5)-10(-3)M, with cationic slopes of 30 and 30.7 mV per concentration decade, were obtained by using sensors 1 and 2, respectively. The third sensor was fabricated by using PVC carboxylate (PVC-COOH). The dissociated COOH groups in the PVC-COOH act as a mediator and/or ionic site. A linear response was obtained over the concentration range of 10(-5)-10(-2)M with a cationic slope of 29 mV per concentration decade. Sensor 4 was fabricated by using 2,6-didodecyl-beta-cyclodextrin as the ionophore, polyurethane (Tecoflex) as a polymeric matrix, and potassium tetraphenyl borate as the ionic site; it showed a linear response over the concentration range of 10(-7)-10(-2)M with a cationic slope of 28.9 mV per concentration decade. The direct potentiometric determination of zolpidem hemitartrate in pure forms by using the 4 proposed sensors gave average recoveries of 98.5+/-0.7, 99.4 +/-0.2, 100.7+/-0.10, and 99.8+/-0.1% for sensors 1-4, respectively. The results obtained by the proposed procedures were statistically analyzed and compared with those obtained by using a reported method. The 4 proposed sensors were also applied successfully to the determination of the drug in tablets and in biological fluids. Average recoveries obtained by using sensors 1, 2, 3, and 4 for drug assay of tablets were 99.6+/-0.6, 100+/-0.7, 99.7+/-0.4, and 99.5+/-0.8%, respectively. The presence of tablet excipients did not interfere with the determination of the drug or with the accuracy and precision of the 4 proposed methods. The methods were also used to determine the drug in the presence of its degradates and thus could be used as stability-indicating methods.     

Application of orthogonal functions to spectrophotometric analysis: Determination of nifuroxime and furazolidone in pharmaceutical formulations

Summary The orthogonal function method has been applied to the simultaneous determination of nifuroxime and furazolidone in admixture without the need of preliminary separation. Two procedures are proposed. The first one involves measurement of a suitable solution of the mixture in the range from 309 nm to 359 nm with 10 nm intervals to determine nifuroxime, and in the range from 345 nm to 395 nm with 10 nm intervals to determine furazolidone. The second procedure involves determination of either components through measurement at the previously mentioned wavelength range while the absorbance of the partner component is measured at its _max; correction of interference is carried out using an calculated absorbance ratio. Both methods were successfully applied to the analysis of market preparations and further application for routine analysis is recommended. Recoveries were in general between 97% and 102%.

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Anwendung von Orthogonalfunktionen in der spektral-photometrischen Analyse: Bestimmung von Nifuroxim und Furazolidon in pharmazeutischen Präparaten

Zusammenfassung Durch Anwendung von Orthogonalfunktionen können Nifuroxim und Furazolidon in einem Gemisch nebeneinander ohne vorausgehende Trennung bestimmt werden. Zwei verschiedene Verfahren werden vorgeschlagen. Bei dem einen erfolgen die Messungen für Nifuroxim im Bereich von 309 bis 359 nm in Intervallen von 10 nm und für Furazolidon von 345 bis 395 ebenfalls im 10 nm-Abstand. Beim zweiten Verfahren wird einer der Bestandteile bei den genannten Wellenlängen gemessen, während die Extinktion des anderen Bestandteils beim Absorptions-maximum gemessen wird. Die Korrektur für die Störung erfolgt über das berechnete Extinktionsverhältnis. Beide Verfahren wurden erfolgreich bei Handelsprodukten angewendet und werden für Routinebestimmungen empfohlen. Wiederfindungsraten lagen im allgemeinen zwischen 97 und 102%.

     

Comparative validated chromatographic methods for the simultaneous determination of caffeine,codeine, paracetamol along with the related compound " p-aminophenol"="" in="" tablets"="

JPC – Journal of Planar Chromatography – Modern TLC - This paper presents two validated chromatographic methods, namely thin-layer chromatography (TLC)–densitometry and...     

A New Comparative Potentiometric Method for Analysis of Omarigliptin Using Three Different Sensors

This work represents first attempt for potentiometric determination of the most recent antidiabetic; omarigliptin. Three sensors, employing potassium tetrakis (p-chlorophenyl) borate as a lipophilic cation exchanger, were developed and compared. One liquid contact ion-selective electrode and two carbon paste-based solid contact ones, plain one and another one modified with polyaniline nanoparticles, were employed. Performances of fabricated sensors were assessed as per IUPAC recommendations. Incorporation of hydrophobic polyaniline nanoparticles as ion-to-electron transducer layer at solid contact/ion-sensitive membrane interface enhanced sensitivity and stability of the third sensor showing LOD of 2.5×10⁻⁷ mol L⁻¹ and slope of 58.57 mV decade⁻¹. The three sensors were applied for omarigliptin determination in presence of its degradation products, in dosage form and spiked human plasma.     

Determination of cimetidine,famotidine, and ranitidine hydrochloride in the presence of their sulfoxide derivatives in pure and dosage forms by high-performance thin-layer chromatography and scanning densitometry

A selective, precise, and accurate method was developed for the determination of cimetidine (C), famotidine (F), and ranitidine hydrochloride (R x HCl) in the presence of their sulfoxide derivatives. The method involves quantitative densitometric evaluation of mixtures of the drugs and their derivatives after separation by high-performance thin-layer chromatography on silica gel plates (10 x 20 cm) with ethyl acetate-isopropanol-20% ammonia (9 + 5 + 4, v/v) as the mobile phase for both C and F and ethyl acetate-methanol-20% ammonia (10 + 2 + 2, v/v) as the mobile phase for R x HCl; Rf values for C, F, and R x HCl and their corresponding derivatives were 0.85 and 0.59, 0.73 and 0.41, and 0.56 and 0.33, respectively. Developing time was approximately 20 min. For densitometric evaluation, peak areas were recorded at 218, 265, and 313 nm for C, F, and R x HCl, respectively. The relationship between concentration and the corresponding peak area was plotted for the ranges of 5-50 microg/spot for C and 2-20 microg/spot for F and R x HCl. Mean recoveries were 100.39 +/- 1.33, 99.77 +/- 1.30, and 100.09 +/- 0.69% for C, F, and R x HCl, respectively. The proposed method was used successfully for stability testing of the pure drugs in the presence of up to 90% of their degradates, in bulk powder and dosage forms. The results obtained were analyzed statistically and compared with those obtained by the official methods.     

Simultaneous determination of caffeine, 8-chlorotheophylline, and chlorphenoxamine hydrochloride in ternary mixtures by ratio-spectra zero-crossing first-derivative spectrophotometric and chemometric methods

A ratio-spectra zero-crossing first-derivative spectrophotometric method and 2 chemometric methods have been used for the simultaneous determination of ternary mixtures of caffeine (A), 8-chlorotheophylline (B), and chlorphenoxamine hydrochloride (C) in bulk powder and dosage forms. In the ratio-spectra zero-crossing first-derivative spectrophotometric technique (1DD), calibration curves were linear in the range of 4-20 microg/mL for A, B, and C (r = 0.9992, 0.9994, and 0.9976, respectively). The measurements were carried out at 212, 209.2, and 231.4 nm for A, B, and C, respectively. The detection limits for A, B, and C were calculated to be 0.24, 0.34, and 0.13 microg/mL, and the percentage recoveries were 99.1 +/- 0.89, 100.1 +/- 0.95, and 100.1 +/- 1.0, respectively. Two chemometric methods, namely, the partial least-squares (PLS) model and the principal component regression (PCR) model, were also used for the simultaneous determination of the 3 drugs in the ternary mixture. A training set consisting of 15 mixtures containing different ratios of A, B, and C was used. The concentration used for the construction of the PLS and PCR models varied between 4 and 25 microg/mL for each drug. These models were used after their validation for the prediction of the concentrations of A, B, and C in mixtures. The detection limits for A, B, and C were calculated to be 0.13, 0.15, and 0.14 microg/mL, respectively, and the percent recoveries were found to be 99.8 micro 0.96, 99.9 micro 0.94, and 99.9 micro 1.18, respectively, for both methods. The 3 proposed procedures are rapid, simple, sensitive, and accurate. No preliminary separation steps or resolution equations are required; thus, they can be applied to the simultaneous determination of the 3 drugs in commercial tablets and suppositories or in quality-control laboratories.