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ABSTRACT: The in vitro protein binding of retinoic acid isomers (isotretinoin and tretinoin) and the antihypertensive drugs (amlodipine and telmisartan) was studied by equilibrium dialysis method. In this study, free fraction of drugs and the % of binding of drugs in the mixture to bovine serum albumin (BSA) were calculated. The influence of retinoic acid isomers on the % of protein binding of telmisartan and amlodipine at physiological pH (7.4) and temperature (37±0.5°C) was also evaluated. The in vitro displacement interaction study of drugs telmisartan and amlodipine on retinoic acid isomers and also interaction of retinoic acid isomers on telmisartan and amlodipine were carried out.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 07/2011; 79(2):384-7. · 2.10 Impact Factor
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ABSTRACT: Simple, accurate, precise, sensitive, and validated HPLC and HPTLC-densitometric methods were developed for simultaneous determination of amlodipine (AML), valsartan (VAL), and hydrochlorothiazide (HYD) in combined tablet dosage form. Method A, the gradient RP-HPLC analysis was performed on a Phenomenex Luna C18 (4.60 mm × 150 mm, 5 µ particle size) column, using a mobile phase consisting of 10 mM ammonium acetate buffer (pH 6.7) and methanol in solvent gradient elution for 20 min at a flow rate of 1 mL min−1. Quantification was carried out using a photodiode array UV detector at 238 nm. The employment of a diode array detector allowed selectivity confirmation by peak purity evaluation. Method B, the HPTLC analysis was carried out on an aluminum-backed sheet of silica gel 60F254 layers using chloroform: glacial acetic acid:n-butyl acetate (8:4:2, v/v/v) as the mobile phase. Quantification was achieved with UV densitometry at 320 nm. The analytical methods were validated according to International Conference on Harmonization (ICH) guidelines. No chromatographic interference from tablet excipients was found and hence these methods are applicable for simultaneous determination of AML, VAL, and HYD in pharmaceutical formulations and biological fluids.
Journal of Liquid Chromatography & Related Technologies 07/2011; 34(12):981-994. · 0.71 Impact Factor
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Jpc-journal of Planar Chromatography-modern Tlc - JPC-J PLANAR CHROMAT-MOD TLC. 01/2008; 21(6):437-439.
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ABSTRACT: The objective of the present study was to develop membrane-moderated transdermal systems of ampicillin sodium and to evaluate them with respect to various in vitro and in vivo parameters. The membrane-type transdermal systems were prepared using a drug with various antinucleant polymers-hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), cellulose acetate phthalate, chitosan, sodium alginate (SA), and sodium carboxymethylcellulose-in an ethanol: pH 4.7 buffer volatile system by the solvent evaporation technique with HPMC as the rate-controlling membrane for all the systems. The swelling properties of the polymers were studied, and drug-polymer interaction studies were performed. The patches were subjected to various physicochemical studies, in vitro release studies, permeation studies, and skin irritation studies. The best patch among the formulations was selected for further in vivo studies. Compared to the other patches, SA exhibited the highest moisture content at 16%; a 21% moisture uptake was found with MC. The release and permeation of the drug from the SA patch was found to be the maximum. The in vivo study of the SA patch exhibited a peak plasma concentration C(max) of 126 microg/mL at T(max) 4 hours. Hence, it can be concluded that hydrophilic ampicillin sodium can be developed as a transdermal delivery system with SA that is an alternative to intravenous administration and has minimal adverse effects.
AAPS PharmSciTech 02/2007; 8(1):7. · 1.43 Impact Factor
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ABSTRACT: A stability-indicating forced-degradation study of valdecoxib was conducted using high performance thin layer chromatography (HPTLC). It was used to analyze valdecoxib as bulk drug and as tablets. Undegraded valdecoxib was eluted with a retardation factor, Rf, of 0.56. Valdecoxib was forcibly degraded by exposure to alkali, acid, oxidation, and light, the greatest degradation occurring under basic conditions. Base-degraded valdecoxib gave an additional peak with an Rf value of 0.76. The calibration curve was linear in the range of 0.2-1 microg/microL with a correlation coefficient of 0.9952. Complete validation was carried out for precision (inter-day, intra-day, repeatability), accuracy, and robustness. All the data were analyzed statistically. This HPTLC procedure shows the reliability needed for use as a stability-indicating method. It can quantify valdecoxib in bulk and in tablets and also resolves the degraded peak of valdecoxib. This method is also useful for studying the degradation pattern and degradation mechanism of valdecoxib.
Journal of Separation Science 08/2006; 29(11):1647-52. · 2.73 Impact Factor
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ABSTRACT: This paper describes two simple, specific, accurate, and precise methods for estimation of olopatadine hydrochloride (OLO) in tablet dosage form. The first method is a stability-indicating isocratic RP-HPLC method. The analysis is performed on an RP-18 column using 0.1% orthophosphoric acid (adjusted to pH 4.5 with triethylamine)-acetonitrile (75 + 25, v/v) mobile phase at a flow rate of 1 mL/min. Paracetamol (PAR) was selected as the internal standard. Retention times of OLO and PAR were 11.30 +/- 0.02 and 4.70 +/- 0.03 min, respectively. For the HPTLC method, precoated silica gel 60 F254 aluminum sheets were used as the stationary phase; the mobile phase was methanol-chloroform-ammonia (8 + 2 + 0.1, v/v/v). The detection of the analyte band was carried out at 301 nm, and its Rf value was 0.46 +/- 0.03. The analytical methods were validated according to International Conference on Harmonization guidelines. Linear regression analysis data for the calibration plots showed a good linear relationship between response and concentration in the range of 0.1-1 microg/mL and 0.1-0.9 microg/band for HPLC and HPTLC, respectively.
Journal of AOAC International 94(6):1815-20. · 1.20 Impact Factor
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ABSTRACT: Some new 3-acetyl-5-(3-chloro-1-benzo[b]thiophen-2-yl)-2-substituted phenyl-2,3-dihydro-1,3,4-oxadiazoles and 2-(3-chloro-1-benzo[b]thiophen-2-yl)-5-substituted phenyl-1,3,4-oxadiazoles have been synthesized and evaluated for antimicrobial activity. Initially, 3-chloro-1-benzo[b]thiophene-2-carbonyl chloride (1) was prepared from cinnamic acid in the presence of chlorobenzene and thionyl chloride. This compound (1) was treated with hydrazine hydrate to afford 3-chloro-1-benzo[b]thiophene-2-carbohydrazine (2) which was further reacted with various aromatic aldehydes to yield hydrazones (3a-h). Further reaction of these hydrazones (3a-h) with acetic anhydride gave 3-acetyl-5-(3-chloro-1-benzo[b]thiophen-2-yl)-2-substituted phenyl-2,3-dihydro-1,3,4-oxadiazoles (4a-h). Reaction of the same compounds (3a-h) in the presence of chloramine-T afforded 2-(3-chloro-1-benzo[b]thiophen-2-yl)-5-substituted phenyl-1,3,4-oxadiazoles (5a-h). The structures of newly synthesized compounds (4a-h) and (5a-h) have been confirmed by spectroscopic techniques such as IR, 1H NMR and elemental analysis. All the compounds were screened for their antibacterial activities against Staphylococcus aureus, Bacillus subtilis. Escherichia coli and Pseudomonas aeruginosa and for antifungal activity against Candida albicans and Asperigillus niger. The compounds exhibited significant antibacterial and moderate antifungal activities. Compounds 4c and 4e were found to be most potent with activities, even better than standard drug ciprofloxacin against S. aureus and B. subtilis.
Acta poloniae pharmaceutica 67(3):247-53. · 0.66 Impact Factor
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ABSTRACT: This paper describes validated HPLC and HPTLC methods for the simultaneous determination of rosuvastatin (ROS) and ezetimibe (EZE) in a combined tablet dosage form. The isocratic RP-HPLC analysis was performed on a Chromolith C18 column (100 x 6 mm id) using 0.1% (v/v) orthophosphoric acid solution (pH 3.5)-acetonitrile (63 + 37, v/v) mobile phase at a flow rate of 1 mL/min at ambient temperature. Quantification was carried out using a photodiode array UV detector at 245 nm over the concentration range of 0.5-10 microg/mL for ROS and EZE. The HPTLC separation was carried out on an aluminum-backed sheet of silica gel 60F(254) layers using n-butyl acetate-chloroform-glacial acetic acid (1 + 8 + 1, v/v/v) mobile phase. Quantification was achieved with UV densitometry at 245 nm over a concentration range of 0.1-0.9 micro/spot for ROS and EZE. The analytical methods were validated according to International Conference on Harmonization guidelines. Low RSD values indicated good precision. Both methods were successfully applied for the analysis of the drugs in laboratory-prepared mixtures and commercial tablets. No chromatographic interference from the tablet excipients was found. These methods are simple, precise, and sensitive, and are applicable for simultaneous determination of ROS and EZE in pure powder and tablets.
Journal of AOAC International 93(4):1222-7. · 1.20 Impact Factor
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Susheel John Varghese, Thengungal Kochupappy Ravi
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ABSTRACT: A simple, rapid, and sensitive LC/electrospray ionization (ESI)-MS method was developed and validated for the simultaneous determination of rosuvastatin (ROS) and ezetimibe (EZE) in human plasma. Following liquid-liquid extraction, the analytes and an internal standard, atorvastatin (ATO), were separated using an isocratic mobile phase comprising 0.1% (v/v) formic acid-methanol (20 + 80, v/v) on an RP-C18 column. Detection was performed on a mass spectrometer by selected ion monitoring using their respective [M-H]- ions, m/z 480 for ROS, m/z 408 for EZE, and m/z 557 for ATO. For both analytes, the method was linear in the range of 0.1 to 10 nglmL. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 4 min made it possible to determine many plasma samples/day. The validated LC/ESI-MS method can be used to study pharmacokinetics, bioavailability, and bioequivalence of combined dosage forms of ROS and EZE.
Journal of AOAC International 96(2):307-12. · 1.20 Impact Factor
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ABSTRACT: Reaction of ethyl-6-methyl–2-oxo-4-aryl-1,2,3,4-tetrahydropyrimidin-5-carboxylates (1a-i) with hydrazine hydrate yielded 6-methyl-2-oxo-4-aryl-1,2,3,4-tetrahydropyrimidin-5-carbohydrazides (2a-i). These products on reaction with cyanogen bromide gave 5-(5-amino-1,3,4-oxadiazol-2-yl)-6-methyl-4-aryl-3,4-dihydropyrimidin-2(1H)-one (3a-i). The resultant aminooxadiazolylpyrimidinones were condensed with isatin to obtain various 3-{[5-(6-methyl-4-aryl-2-oxo-1,2,3,4-tetrahydropyrimidin-5-yl)-1,3,4-oxadiazol-2-yl]-imino}-1,3-dihydro-2H-indol-2-ones (4a-i). These products were characterized by IR, 1H NMR, mass spectra and elemental analysis. Products 4a-i revealed promising antibacterial, antifungal and antioxidant activity.
Acta pharmaceutica (hfd-fg-ap@zg.htnet.hr); Vol.58 No.1.
