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At least 1,135 records · Page 63Linked to original sources
PubMed1992

The assay and resolution of the beta-blocker atenolol from its related impurities in a tablet pharmaceutical dosage form.

For the complete resolution and determination of the beta-blocker atenolol and its manufacturing impurities a high-performance liquid chromatographic method is developed using structured optimization techniques. The method utilizes a 300 x 3.9 mm i.d. stainless steel column packed with mu Bondapak C18 and a mobile phase containing methanol-25 mM potassium dihydrogen orthophosphate containing 0.06% (v/v) dibutylamine (20:80, v/v) (pH 3.0). The flow rate of 1.0 ml min-1 is used and a detection wavelength of 226 nm. The linearity and repeatability are good for the present compound over the range 1.5-510.0 micrograms ml-1 (r greater than 0.99 and RSD 0.27%, n = 10). Application of the method to 50 and 100 mg tablets gave recoveries of 99% (w/w) and reproducibilities of (RSD) 1.1 and 0.52%, respectively (n = 5). The manufacturing impurities are found to be greater than 0.5% (w/w) of the atenolol peak.

Atenolol↗
PubMed1994

Spectrofluorimetric analysis of cefuroxime in pharmaceutical dosage forms.

A fluorimetric method has been developed for the quantitative analysis of cefuroxime, based upon the formation of a fluorescent derivative formed by alkaline hydrolysis with 1.0 M sodium hydroxide and heating at 100 degrees C for 60 min. The fluorescent product gave excitation and emission maxima at 380 and 436 nm, respectively. The method was performed in aqueous solution adjusted to pH 10.5 by addition of phosphate buffer solution. The calibration curve was found to be linear in the range of concentrations 0.050-1.70 micrograms ml-1. The lower limit of detection was 1.0 x 10(-2) micrograms ml-1. The method was applied to authentic pharmaceutical preparations containing cefuroxime sodium or cefuroxime axetil, the 1-(acetyloxy) ethyl ester of the drug, and was found to be satisfactory. Cefuroxime sodium was also determined in physiological solutions used to prepare intravenous infusions of this antibiotic.

Cefuroxime↗
PubMed1995

Second-order derivative spectrophotometric assay for imipramine hydrochloride and diazepam in pure admixtures and in dosage forms.

The determination of imipramine HCl and diazepam in tablets by derivative spectrophotometry is described. The drugs in combined preparations have been quantified using the second-order derivative spectra of their solutions in 0.1 M HCl. The method has been applied to pure drug mixtures as well as commercial preparations and was found to be precise and reproducible. Compliance of Beer's Law was observed in the concentration range of 10-70 micrograms ml-1 for imipramine HCl and 2-8 micrograms ml-1 for diazepam. Lower limits of detection at the 95% confidence level were 1.96 micrograms ml-1 for imipramine HCl and 0.21 microgram ml-1 for diazepam.

Diazepam↗
PubMed1995

High-performance liquid chromatographic determination of bisacodyl in pharmaceutical dosage forms marketed in Australia.

HPLC methods have been developed for the assay of bisacodyl in various pharmaceutical forms. The extraction procedures are simple and the HPLC conditions separate bisacodyl from its degradation products. The chromatography was performed using a Merck LiChrospher RP-select B column, a mobile phase of 55% acetonitrile/45% 0.05 M KH2PO4 and detection by UV at 214 nm.

Bisacodyl↗
PubMed1991

Intragastric positioning of two concurrently ingested pharmaceutical matrix dosage forms.

A triple nuclide scintigraphic technique is presented for the precise and lasting intragastric monitoring in man of two concurrently ingested hydrophilic matrix pharmaceutical forms. After in vitro testing of various labels, ion exchange resin-coupled 201T1- and 111In-oxinate were selected for their release characteristics. 99mTc-pertechnetate oral solution was used to selectively delineate the stomach. This technique was validated on healthy volunteers. It allowed measurement of the effects on gastric residence time of galenic parameters (size, density of matrices), as well as of physiological parameters such as subject posture.

Adult↗
PubMed2005

A level A in vitro/in vivo correlation in fasted and fed states using different methods: applied to solid immediate release oral dosage form.

The first purpose of this study was to simulate the impact of food intake on drug release and absorption in vivo using a novel in vitro system which mimics the gastro-intestinal (GI) tract in man. The drug studied was acetaminophen in the form of immediate release (IR) tablets. The second purpose was to establish a level A in vitro/in vivo correlation that could predict the bioavailability of a drug instead of using difficult, time-consuming and expensive in vivo bioequivalence studies. The artificial digestive system was used to estimate the availability of acetaminophen IR tablets for absorption in fasted and fed states. The same study was performed in vivo under similar conditions. A comparison study was carried out between the classical and the novel methods to estimate the efficacy of the new in vitro system to simulate the influence of food on drug release and absorption in vivo. A level A in vitro/in vivo correlation was established with a correlation coefficient of 0.9128 and 0.9984 in the fasted and fed states, respectively. Compared to USP II method, the novel in vitro model demonstrated a high level of efficacy in mimicking the behaviour of acetaminophen IR tablets in vivo in fasted and fed states.

Acetaminophen↗
PubMed2004

Spectrophotometric determination of some beta-blockers in dosage forms based on complex formation with Cu(II) and Co(II).

Four sensitive and accurate spectrophotometric methods have been developed for the assay of Acebutolol Hydrochloride (ACH), Atenolol (ATE) and Propranolol Hydrochloride (PRH), which are based on the complexation of drugs with copper(II) (Cu(II)) and cobalt(II) (Co(II)). The coloured products are measured at 613, 694, 548 and 614 nm for ACH-Co(II), ATE-Cu(II), PRH-Cu(II) and PRH-Co(II) method, respectively. The optimization of various experimental conditions is described. Conformity with Beer's Law was evident over a concentration range in the of 2 x 10(-5) - 1 x 10(-2) mol/L. The molar absorptivity, detection and quantification limits are calculated. The results obtained showed good recoveries of 100.2 +/- 1.1, 100.3 +/- 1.2, 100.75 +/- 1.0 and 99.55 +/- 1.1 % with relative standard deviations of 0.410, 0.490, 0.161 and 0.140 % for ACH-Co(II), ATE-Cu(II), PRH-Cu(II) and PRH-Co(II) method, respectively. They were applied to the analysis of tablet forms of the drugs and the results were statistically compared with those obtained by official and literature methods using t- and F-tests. There were no significant difference among the mean values and precisions of the methods at 95% confidence level.

Adrenergic beta-Antagonists↗
PubMed2005

Application of stability-indicating HPTLC method for quantitative determination of metadoxine in pharmaceutical dosage form.

A sensitive, selective, precise and stability-indicating high-performance thin-layer chromatographic method for analysis of metadoxine both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of acetone-chloroform-methanol-ammonia (7.0:4.0:3.0:1.2, v/v/v/v). Densitometric analysis of metadoxine was carried out in the absorbance mode at 315 nm. This system was found to give compact spots for metadoxine (Rf value of 0.45+/-0.02, for six replicates). Metadoxine was subjected to acid, alkali and neutral hydrolysis, oxidation, dry and wet heat treatment and photo and UV degradation. The drug undergoes degradation under all stress conditions. Also, the degraded products were well resolved from the pure drug with significantly different Rf values. The method was validated for linearity, precision, robustness, LOD, LOQ, specificity and accuracy. Linearity was found to be in the range of 100-1500 ng/spot with significantly high value of correlation coefficient r2=0.9997+/-1.02. The linear regression analysis data for the calibration plots showed good linear relationship with r2=0.9999+/-0.58 in the working concentration range of 200-700 ng/spot. The mean value of slope and intercept were 0.11+/-0.04 and 18.73+/-1.89, respectively. The limits of detection and quantitation were 50 and 100 ng/spot, respectively. Statistical analysis proves that the method is repeatable and specific for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability-indicating one. Moreover, the proposed HPTLC method was utilized to investigate the kinetics of acid and base degradation process. Arrhenius plot was constructed and activation energy was calculated respectively for acid and base degradation process.

Calibration↗
PubMedDate not supplied

Voltammetric determination of montelukast sodium in dosage forms and human plasma.

The voltammetric behaviour of montelukast (MKST) was studied using cyclic voltammetry, direct current (DCt), differential pulse polarography (DPP) and alternating current (ACt) polarography. MKST exhibited well-defined cathodic waves over the range pH range 1-5. No anodic waves were produced over the same pH range. At pH 1, the analytical pH; the diffusion current constant (Id) was 2.2+/-0.01 microA l mmol-1. The current concentration plot was rectilinear over the range 2-20 microg ml-1 with correlation coefficient (n=10) of 0.9943. The lower limit of detection (S/N=2) was 0.2 microg ml-1 (3.41x10(-7) M). The wave has been characterised as being diffusion-controlled, although adsorption phenomenon played a limited role in the electrode reaction. The proposed method was successfully applied to the determination of MKST in commercial tablets, and results were in agreement with those given with a reference HPLC method. The method was further extended to the in vitro determination of the drug in spiked human plasma. The mean % recovery (n=5) was 101.38+/-3.85. The number of electrons transferred in the reduction process could be accomplished and a proposal of the electrode reaction was proposed.

Acetates↗
PubMed2003

Design and monitoring of photostability systems for amlodipine dosage forms.

Photostability of amlodipine (AML) has been monitored in several pharmaceutical inclusion systems characterized by plurimolecular aggregation of the drug and excipients with high molecular weight. Several formulations including cyclodextrins, liposomes and microspheres have been prepared and characterized. The photodegradation process has been monitored according to the conditions suggested by the ICH Guideline for photostability testing, by using a light cabinet equipped with a Xenon lamp and monitored by spectrophotometry. The formulations herein tested have been found to be able to considerably increase drug stability, when compared with usual pharmaceutical forms. The residual concentration detected in the inclusion complexes with cyclodextrins and liposomes was 90 and 77%, respectively, while a very good value of 97% was found for microspheres, after a radiant exposure of 11,340 kJm(-2).

Amlodipine↗
PubMed2004

In vitro and in vivo percutaneous absorption of topical dosage forms: case studies.

This article evaluated the influence of vehicle compositions on topical drug availability. In vitro drug release and in vivo experiments were performed in case of the hydrophilic ketamine hydrochloride and the lipophilic piroxicam. Ketamine hydrochloride is a NMDA receptor antagonist that has been useful for anesthesia and analgesia. The study of transdermal ketamine delivery is a novelty, because nobody has investigated the hypnotic effects of ketamine after this administration route. In vitro measurements gave a good basis for screening among the developed products. The physiological changes after ketamine administration showed, that there were significant differences among the parameters tested (breathing rate, duration of sleep) from the developed products (hydrogel, lyotropic liquid crystal and o/w cream) compared to the reference product (Carbopol gel). The in vivo feedback for piroxicam was the measurement of the anti-inflammatory activity by edema inhibition percentage. Significant differences were measured in case of the developed systems compared to the reference.

Administration, Cutaneous↗