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At least 1,153 records · Page 64Linked to original sources
PubMed2006

Floating matrix dosage form for phenoporlamine hydrochloride based on gas forming agent: in vitro and in vivo evaluation in healthy volunteers.

Phenoporlamine hydrochloride is a novel compound that is used for the treatment of hypertension. The purpose of this study was to develop a sustained release tablet for phenoporlamine hydrochloride because of its short biological half-life. Three floating matrix formulations of phenoporlamine hydrochloride based on gas forming agent were prepared. Hydroxypropyl methylcellulose K4M and Carbopol 971P NF were used in formulating the hydrogel drug delivery system. Incorporation sodium bicarbonate into matrix resulted in the tablet floating over simulated gastric fluid for more than 6h. The dissolution profiles of all tablets showed non-Fickian diffusion in simulated gastric fluid. Moreover, release of the drug from these tablets was pH-dependent. In vivo evaluations of these formulations of phenoporlamine hydrochloride were conducted in six healthy male human volunteers to compare the sustained release tablets with immediate release tablets. Data obtained in these studies demonstrated that the floating matrix tablet containing more Carbopol was capable of sustained delivery of the drug for longer periods with increased bioavailability and the relative bioavailability of formulation (containing 25% Carbopol 971P NF, 8.3% HPMC K4M) showed the best bioequivalency to the reference tablet (the relative bioavailability was 1.11+/-0.19).

Acrylates↗
PubMed2006

Development and in vitro evaluation of a novel floating multiple unit dosage form obtained by melt pelletization.

The feasibility of preparing floating pellets by melt pelletization was investigated. The pellets were prepared in a high shear mixer. Formulations were based on a mixture of Compritol and Precirol as lipidic binders and on sodium bicarbonate as a gas-generating agent. The floating ability of the pellets was evaluated in vitro. Good floating capabilities were obtained for formulations containing the gas-generating agent in both the inner matrix and the outer coating layer of the pellets. As an example, a placebo formulation containing 50% lactose 450 Me, 22% Compritol, 15% Precirol, 8% sodium bicarbonate and 5% Methocel K100 (w/w) in the inner matrix, and 66% Precirol and 34% sodium bicarbonate (w/w) as a coating effervescent layer, showed very good floating capabilities. The percentage of floating placebo pellets was around 80% after 1 h and still above 75% for 23 h. Floating pellet formulations with high drug content, based on the use of tetracycline hydrochloride and theophylline were also evaluated. They showed a comparable floating ability to placebo formulations, combined with sustained release properties thanks to the lipophilic character of the binders used.

Ciprofloxacin↗
PubMed2005

Development and validation of RP-HPLC and ultraviolet spectrophotometric methods of analysis for the quantitative estimation of antiretroviral drugs in pharmaceutical dosage forms.

A high-performance liquid chromatographic and an UV spectrophotometric method were developed and validated for the quantitative determination of three antiretroviral drugs viz. Lamivudine, Stavudine and Nevirapine that constitute one of the first line regimens in antiretroviral therapy. The different analytical performance parameters such as linearity, precision, accuracy, specificity, limit of detection (LOD) and limit of quantification (LOQ) were determined according to International Conference on Harmonization ICH Q2B guidelines. Chromatography was carried out by isocratic technique on a reversed-phase C-18 SYMMETRY column with mobile phase based and optimized depending on the polarity of the molecules. The UV spectrophotometric determinations were performed at 270, 265 and 313 nm for Lamivudine, Stavudine and Nevirapine, respectively. The linearity of the calibration curves for each analyte in the desired concentration range is good (r(2)>0.999) by both the HPLC and UV methods. Both the methods were accurate and precise with recoveries in the range of 97 and 103% for all the three drugs and relative standard deviation (R.S.D.) <5%. Moreover, the accuracy and precision obtained with HPLC correlated well with the UV method which implied that UV spectroscopy can be a cheap, reliable and less time consuming alternative for chromatographic analysis. The proposed methods are highly sensitive, precise and accurate and hence were successfully applied for the reliable quantification of API content in the commercial formulations of Lamivudine, Stavudine and Nevirapine.

Anti-HIV Agents↗
PubMed2004

Determination of cetirizine dihydrochloride, related impurities and preservatives in oral solution and tablet dosage forms using HPLC.

An HPLC method was developed and validated for the determination of cetirizine dihydrochloride (CZ) as well as its related impurities in commercial oral solution and tablet formulations. Furthermore, two preservatives associated with the drug formulations, namely, propyl (PP) and butylparabens (BP) were successfully determined by this method. The chromatographic system used was equipped with a Hypersil BDS C18, 5 microm column (4.6 x 250 mm) and a detector set at 230 nm in conjunction with a mobile phase of 0.05 M dihydrogen phosphate:acetonitrile:methanol:tetrahydrofuran (12:5:2:1, v/v/v/v) at a pH of 5.5 and a flow rate of 1 ml min(-1). The calibration curves were linear within the target concentration ranges studied, namely, 2 x 10(2) - 8 x 10(2) microg ml(-1) and 1-4 microg ml(-1) for CZ, 20-100 microg ml(-1) for preservatives and 1-4 microg ml(-1) for CZ related impurities. The limits of detection (LOD) and quantitation (LOQ) for CZ were, respectively, 0.10 and 0.34 microg ml(-1) and for CZ related impurities were in the ranges of 0.08-0.26 microg ml(-1) and 0.28-0.86 microg ml(-1), respectively. The method proved to be specific, stability indicating, accurate, precise, robust and could be used as an alternative to the European pharmacopoeial method set for CZ and its related impurities.

Calibration↗
PubMed2005

Determination of bisphenol diglycidyl ethers in topical dosage forms.

A method involving extraction and LC-ESI-MS-MS detection of BADGE, BFDGE, BADGE*H2O, BADGE*2H2O, BADGE*HCl, BADGE*H2O*HCl, BADGE.2HCl and BFDGE*2HCl in aqueous cream was developed and validated. Initially, empty internally lacquered aluminum container closure systems were extracted with isopropanol as an attempt to estimate the upper limit of extractable bisphenol diglycidyl ethers present in lacquer. Six of the eight potential bisphenol diglycidyl ethers were quantified. In an accelerated experiment, on aqueous cream stored in lacquered aluminum tubes at 70 degrees C, all derivatives except BADGE*2HCl and BFDGE*2HCl were extracted from cream samples and quantified as an attempt to estimate the upper limit of compounds leaching to the cream. Detection limits were from 0.3+/-0.2 to 3.4+/-0.7 microgl(-1). Recoveries were determined for all compounds at three concentration levels (mean 63+/-6%). Mean inter-day and mean intra-day precision was 7+/-2 and 13+/-6%, respectively. Three commercially available creams were obtained from a local community pharmacy and analysed for bisphenol diglycidyl ethers. BADGE, BADGE*H2O, BADGE*2H2O and BADGE*H2O*HCl were detected and quantified. In conclusion, the developed method allows for the extraction and detection of bisphenol diglycidyl ethers originating from the epoxy phenol lacquer used in aluminum tubes. This study does not indicate that they leach into aqueous cream in significant amounts under normal storage conditions.

Benzhydryl Compounds↗
PubMed2006

Determination of paracetamol in pure and pharmaceutical dosage forms by pulse perturbation technique.

A new procedure for kinetic determination of paracetamol in pharmaceuticals is proposed. The method is based on potentiometric monitoring of the concentration perturbations of the matrix reaction system being in a stable non-equilibrium stationary state close to the bifurcation point. In the case considered as the matrix system, the Bray-Liebhafsky oscillatory reaction is used. The response of the matrix system to the perturbations by different concentrations of paracetamol is followed by a Pt-electrode. Proposed method relies on the linear relationship between maximal potential shift, DeltaEm, and the logarithm of added paracetamol amounts. It is obtained in optimized experimental conditions for variable amounts of paracetamol in the range 0.0085 and 1.5 micromol. The sensitivity and precision of proposed method were quite good (0.0027 micromol as the limit of detection and 2.4% as R.S.D.). Some aspects of possible chemical interactions between paracetamol and matrix are discussed. Applicability of the proposed method to the direct determination of paracetamol in pharmaceutical formulations was demonstrated.

Acetaminophen↗
PubMed2006

Determination of nelfinavir mesylate as bulk drug and in pharmaceutical dosage form by stability indicating HPLC.

A isocratic, selective, accurate and stability indicating HPLC method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. A CN chromatographic column (250 mmx4.6 mm, 5 microm) was used for the separation at 40 degrees C. The mobile phase consisted of a mixture of acetonitrile (MeCN) and 25 mM monobasic ammonium phosphate (containing 25 mM triethylamine, pH 3.4 with phosphate acid) (40:60, v/v) was delivered at a flow rate of 1.0 ml/min with detection at 210 nm. The developed method was validated in terms of selectivity, linearity, limit of quantitation, precision, accuracy and solution stability. As the proposed LC method achieved satisfactory resolution between nelfinavir mesylate, its degradation products, intermediate product possibly present in nelfinavir drug substance and other impurities in the end product before refining in the final step of synthetic process, it can be employed as a stability indicating one, used for the synthetic process control and determination of nelfinavir mesylate in pharmaceutical preparations.

Chromatography, High Pressure Liquid↗
PubMed2006

Determination of Cu, Fe, Mn and Zn by flame atomic absorption spectrometry in multivitamin/multimineral dosage forms or tablets after an acidic extraction.

This work presents the development of a methodology for the determination of Cu, Fe, Mn and Zn in samples of multivitamin/multimineral tablets, by flame atomic absorption spectrometry (FAAS), after extraction of the analytes with diluted hydrochloric acid solution. Several parameters that could influence the extraction process such as acid extraction solution concentration and nature, mixing mode (ultrasonic or magnetic stirring), extraction time and sample composition were evaluated. The obtained results showed that Fe, Mn and Zn were easily extracted with 1 mol/L HCl solution after 5 min of mixing with either ultrasonic or magnetic stirring for all studied samples. On the other hand, Cu extraction appeared to be more complex since it could only be extracted at the same conditions for silicate-free samples. For samples containing silicates the time of contact between solid sample and extraction solution presented remarkable influence, being necessary up to 12 h to achieve quantitative recovery with 1 mol/L HCl solution. The developed methodology was applied in the determination of Cu, Fe, Mn and Zn in seven commercially available multivitamin/multimineral tablets. The results obtained with the developed method were compared with those obtained after total digestion of samples using a closed-vessel microwave oven device.

Acids↗
PubMed2000

The voltammetric study and determination of ramipril in dosage forms and biological fluids.

The voltammetric behavior of ramipril was studied using cyclic voltammetry, direct current polarography (DCt), differential pulse polarography (DPP) and alternating current polarography (ACt). Ramipril developed well-defined cathodic waves in Britton-Robinson buffers over the pH range 6-12. The waves were characterized as being diffusion-controlled, irreversible and partially affected by adsorption phenomenon. The diffusion-current constant (Id) was 1.24 +/- 0.02. The current-concentration plots were rectilinear over the range 10-50, 4-40 and 0.16-12 micrograms/ml in the DCt, DPP and ACt modes, respectively, with a minimum detectability (S/N = 2) of 0.02 microgram/ml (4.8 x 10(-8) M) using the latter mode. The proposed method was successfully applied to the determination of ramipril in commercial tablets. Hydrochlorothiazide, which is frequently co-formulated with ramipril, did not interfere with the assay. Furthermore, the proposed method was applied to the determination of ramipril in urine and plasma adopting the ACt technique. The percentage recoveries were 97.12 +/- 0.56 and 94.97 +/- 0.62%, respectively. A pathway for the electrode reaction was proposed.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Statistical optimization of a reversed-phase ion-pair liquid chromatographic method for the analysis of tolmetin sodium in dosage forms.

A quantitative liquid chromatographic method in which tolmetin sodium is separated from an internal standard on a C18 column with detection at 317 nm has been developed with the aid of two statistical optimization procedures. The effects of simultaneously varying the pH, methanol-water ratio, and the concentrations of buffer and ion-pair reagent in the mobile phase were studied. A two-level factorial design was used to investigate the interactions among the variables, and the sequential simplex procedure was used to optimize the separation. A novel quality criterion was developed for the simplex optimization. Using synthetic mixtures, the mean recovery value +/- S.D. (n = 6) of tolmetin sodium was 98.7 +/- 0.19% for tablets and 98.5 +/- 0.12% for capsules. The assay results for commercial tablets and capsules were comparable to those obtained by the USP XXI procedure.

Chromatography, High Pressure Liquid↗