50 research outputs found
Development and validation of stability indicating method for determination of sertraline following ICH guidlines and its determination in pharmaceuticals and biological fluids
<p>Abstract</p> <p>Background</p> <p>Sertraline is a well known antidepressant drug which belongs to a class called selective serotonin reuptake inhibitor. Most published methods do not enable studying the stability of this drug in different stress conditions.</p> <p>Results</p> <p>Two new methods were developed for the determination of sertraline (SER). Both methods are based on coupling with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in borate buffer of pH 7.8 and measuring the reaction product spectrophotometrically at 395 nm (Method I) or spectrofluorimetrically at 530 nm upon excitation at 480 nm (Method II). The response-concentration plots were rectilinear over the range 2-24 μg/mL and 0.25-5 μg/mL for methods I and II respectively with LOD of 0.18 μg/mL and 0.07 μg/mL, and LOQ of 0.56 μg/mL and 0.21 μg/mL for methods I and II, respectively.</p> <p>Conclusion</p> <p>Both methods were applied to the analysis of commercial tablets and the results were in good agreement with those obtained using a reference method. The fluorimetric method was further applied to the in vivo determination of SER in human plasma. A proposal of the reaction pathway was presented. The spectrophotometric method was extended to stability study of SER. The drug was exposed to alkaline, acidic, oxidative and photolytic degradation according to ICH guidelines. Moreover, the method was utilized to investigate the kinetics of oxidative degradation of the drug. The apparent first order rate constant and t<sub>1/2 </sub>of the degradation reaction were determined.</p
Assaying Total Carotenoids in Flours of Corn and Sweetpotato by Laser Photoacoustic Spectroscopy
This study describes the application of the laser photoacoustic spectroscopy (PAS) for quantification of total carotenoids (TC) in corn flours and sweetpotato flours. Overall, thirty-three different corn flours and nine sweetpotato flours were investigated. All PAS measurements were performed at room temperature using 488-nm argon laser radiation for excitation and mechanical modulation of 9 and 30 Hz. The measurements were repeated within a run and within several days or months. The UV–Vis spectrophotometry was used as the reference method. The concentration range that allows for the reliable analysis of TC spans a region from 1 to 40 mg kg−1 for corn flours and from 9 to 40 mg kg−1 for sweetpotato flours. In the case of sweetpotato flours, the quantification may extend even to 240 mg kg−1 TC. The estimated detection limit values for TC in corn and sweetpotato flours were 0.1 and 0.3 mg kg−1, respectively. The computed repeatability (n = 3–12) and intermediate precision (n = 6–28) RSD values at 9 and 30 Hz are comparable: 0.1–17.1% and 5.3–14.7% for corn flours as compared with 1.4–9.1% and 4.2–23.0% for sweetpotato flours. Our results show that PAS can be successfully used as a new analytical tool to simply and rapidly screen the flours for their nutritional potential based on the total carotenoid concentration
Utility of certain nucleophilic aromatic substitution reactions for the assay of pregabalin in capsules
<p>Abstract</p> <p>Background</p> <p>Pregabalin (PG) is an anticonvulsant, analgesic and anxiolytic drug. A survey of the literature reveals that all the reported spectrophotometric methods are either don't offer high sensitivity, need tedious extraction procedures, recommend the measurement of absorbance in the near UV region where interference most probably occurs and/or use non specific reagent that don't offer suitable linearity range.</p> <p>Results</p> <p>Two new sensitive and simple spectrophotometric methods were developed for determination of pregabalin (PG) in capsules. Method (I) is based on the reaction of PG with 1,2-naphthoquinone-4-sulphonate sodium (NQS), yielding an orange colored product that was measured at 473 nm. Method (II) is based on the reaction of the drug with 2,4-dinitrofluorobenzene (DNFB) producing a yellow product measured at 373 nm. The different experimental parameters affecting the development and stability of the reaction product in methods (I) and (II) were carefully studied and optimized. The absorbance-concentration plots were rectilinear over the concentration ranges of 2-25 and 0.5-8 μg mL<sup>-1 </sup>for methods (I) and (II) respectively. The lower detection limits (LOD) were 0.15 and 0.13 μg mL<sup>-1 </sup>and the lower quantitation limits (LOQ) were 0.46 and 0.4 μg mL<sup>-1 </sup>for methods (I) and (II) respectively.</p> <p>Conclusion</p> <p>The developed methods were successfully applied to the analysis of the drug in its commercial capsules. The mean percentage recoveries of PG in its capsule were 99.11 ± 0.98 and 100.11 ± 1.2 (n = 3). Statistical analysis of the results revealed good agreement with those given by the comparison method. Proposals of the reaction pathways were postulated.</p
Separation of phthalates by cyclodextrin modified micellar electrokinetic chromatography: Quantitation in perfumes
Spectrophotometric determination of tizanidine and orphenadrine via ion pair complex formation using eosin Y
A simple, sensitive and rapid spectrophotometric method was developed and validated for the determination of two skeletal muscle relaxants namely, tizanidine hydrochloride (I) and orphenadrine citrate (II) in pharmaceutical formulations. The proposed method is based on the formation of a binary complex between the studied drugs and eosin Y in aqueous buffered medium (pH 3.5). Under the optimum conditions, the binary complex showed absorption maxima at 545 nm for tizanidine and 542 nm for orphenadrine. The calibration plots were rectilinear over concentration range of 0.5-8 μg/mL and 1-12 μg/mL with limits of detection of 0.1 μg/mL and 0.3 μg/mL for tizanidine and orphenadrine respectively. The different experimental parameters affecting the development and stability of the complex were studied and optimized. The method was successfully applied for determination of the studied drugs in their dosage forms; and to the content uniformity test of tizanidine in tablets
Rectal indomethacin alone versus indomethacin and prophylactic pancreatic stent placement for preventing pancreatitis after ERCP: study protocol for a randomized controlled trial
Toxicologie de la reproduction : intérêt et interprétation
Les études de toxicologie de la reproduction sont partie intégrante du dossier non
clinique fourni par les laboratoires lors d’une demande d’autorisation de mise sur le
marché d’un médicament. Elles sont conduites selon des protocoles réglementés et approuvés
au niveau international. Ces études sont réalisées de telle sorte qu’elles permettent
d’évaluer le risque encouru tout au long d’un cycle de reproduction. Elles vont ainsi
étudier l’impact du produit sur les fonctions de reproduction mâle et femelle, la
gestation et le développement embryonnaire et fœtal, la mise bas et le développement
postnatal des jeunes. L’interprétation des résultats et le calcul des marges de sécurité
permettra une évaluation du risque raisonnée et la réalisation de recommandations tant
dans le résumé des caractéristiques du produit (RCP) qu’auprès des prescripteurs
1H and13C NMR data to aid the identification and quantification of residual solvents by NMR spectroscopy
Novel approach for UPLC-ESI-Tandem mass spectrometric method for simultaneous determination of olmesartan medoxomil and hydrochlorothiazide in their pharmaceutical combination with kinetic studies of forced degradation
A simple, robust ultra-performance liquid chromatography coupled to ESI-Tandem mass spectrometric (UPLC-MS/MS) technique was developed for the simultaneous quantitation of olmesartan medoxomil (OLM) and hydrochlorothiazide (HCT) in bulk and their combined pharmaceutical formulation. Chromatographic separation was done on a Hypersil gold 50×2.1 mm (1.9 μm) column, with gradient elution of mobile phase consisted of acetonitrile and 0.1% formic acid aqueous solution. Detection of analytes was carried out using selective reaction monitoring (SRM) mode on a triple quadrupole mass spectrometer coupled with electrospray ionization (ESI). Linearity was achieved over concentration ranges of 2.0-200.0 and 3.0-50.0 ng/mL for OLM and HCT, respectively. Intra and inter day reproducibility were acceptable. The lower limits of detection were found to be 0.627 and 0.583 ng/mL and lower limits of quantitation were 1.900 and 1.767 ng/mL for OLM and HCT, respectively. The method was successfully applied for determination the cited drugs in their combined pharmaceutical dosage form. The method was applied to study the kinetic of forced degradation of both drugs under different conditions. The method was validated according to ICH guidelines and there is no significance difference between the proposed method and the reported method. The simplicity and sensitivity of this method allows the utilization of method in quality control of the cited drugs