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At least 649 records · Page 36Linked to original sources
PubMed1992

Genotoxic action of an aqueous extract of Heliotropium curassavicum var. argentinum.

Heliotropium curassavicum var. argentinum is widely employed in gout, rheumatism, neuralgias, arteriosclerotic disorders, muscular algias, phlebitis, varix and other illnesses. In order to analyze the genotoxic effect produced in vitro by this medicinal plant, chromosomal aberrations (CA), mitotic index (MI) and anaphase delay (AD) were studied in the CHO cell line, with and without the addition of S9 mix. Prepared according to the Argentine pharmacopeia 0.1, 1, 10 and 100 micrograms/ml plant decoction (aqueous extract) were assayed. One hundred cells per culture were studied for CA and AD, while MI was calculated for 2000 nuclei. The results revealed a significant increase in the percentage of abnormal metaphases (p less than 0.001) and in total aberrations (p less than 0.001). Both the MI and the AD affected the cell cycle. All results were enhanced by the addition of an S9 fraction. The toxic effect could be associated with pyrrolizidine alkaloids and their N-oxides, which through a process of in vitro metabolism become activated by microsomal oxidation and change into pyrrolic derivatives.

Analysis of Variance↗
PubMed1978

Preparation and properties of biologically active fluorescent heparins.

Hog mucosal heparin (N-sulfate, 0.84 mol; O-sulfate, 1.55 mol; N-acetyl, 0.12 mol; anticoagulant activity assayed by the method of U.S. Pharmacopeia, 161 USP units/mg) or its partially N-desulfated heparin (N-sulfate, 0.71 mol; O-sulfate, 1.47 mol; N-acetyl, 0.12 mol; anticoagulant activity, 117 USP units/mg/ was reacted with 5-isothiocyanatofluorescein in 0.5 M carbonate buffer (pH 8.5) at 35 degrees C for 6 h to yield the corresponding N-fluoresceinylthiocarbamoyl heparins (lambdaem 516 nm, lambdaex 491 nm; degree of substitution 0.006 and 0.013, respectively, anticoagulant activity, 174 and 140 USP units/mg, respectively). The fluorescent heparin (degree of substitution, 0.006; 174 USP units/mg) was injected into rabbits intravenously. The half-life of the fluorescent heparin determined by fluorometry was 24 min, that determined by the clotting time assay was 39 min. The time-course of concentration and the half-life of the fluorescent heparin and of the starting heparin obtained by the clotting time assay were virtually identical.

Animals↗
PubMed1983

Ethnopharmacology of ska María Pastora (Salvia divinorum, Epling and Játiva-M.).

Salvia divinorum is a perennial labiate used for curing and divination by the Mazatec Indians of Oaxaca, Mexico. The psychotropic effects the plant produces are compared to those of the other hallucinogens employed by the Mazatecs, the morning glory, Rivea corymbosa L., Hallier f. and the psilocybin-containing mushrooms. A discussion of the role of ska María Pastora in the native "pharmacopeia" is based on previous reports and fieldwork by the authors, with a Mazatec shaman.

Hallucinogens↗
PubMed1991

High-performance liquid chromatographic method for the assay of verapamil hydrochloride and related compounds in raw material.

A modification of the USP HPLC method [ United States Pharmacopeia XXII, pp. 1444-1446] for the assay of the purity of verapamil hydrochloride has been evaluated for the determination of the drug content and related compounds in drug raw material. The method enables the resolution of 16 related compounds from the parent drug and, in most cases, from each other. The minimum quantifiable amount for most related compounds is less than 0.05%. Six drug raw material samples are analysed and the total impurities found to be 0.3% or less. All drug assay values were within the USP recommended limits of 99.0-100.5%.

Chromatography, High Pressure Liquid↗
PubMed1991

Vitamins B1 and B6 tubular electrodes as FIA detectors; their use in the analysis of pharmaceutical products.

Ion-selective electrodes without an inner reference solution and tubular potentiometric detectors for the determination of vitamins B1 and B6 in pharmaceutical preparations by flow injection analysis (FIA) are reported. The membranes were prepared with the vitamin tetra(2-chlorophenyl)borate (TCPB) dissolved in o-nitrophenyloctyl ether (o-NPOE) and immobilized on PVC. Intrinsic behaviour of the tubular detectors was assessed using a low-dispersion single-channel FIA manifold and was compared with conventionally-shaped electrodes using the same membrane. Data obtained in the determination of vitamins B1 and B6 in pharmaceutical preparations with a double channel flow injection manifold incorporating the tubular detectors are presented and compared with those obtained by the U.S. Pharmacopeia method and by direct potentiometry with conventionally-shaped electrodes.

Electrodes↗
PubMed1991

Derivative spectrophotometric assay of acetaminophen and spectrofluorimetric determination of its main impurity.

Second derivative UV spectrophotometry proved to be a useful tool for the determination of acetaminophen, even in the presence of high amounts of the impurity, 4-aminophenol and the background effect caused by dissolved excipients of some dosage forms. The fluorimetric method used for the estimation of 4-aminophenol impurity is less sensitive than the colorimetric methods used in the pharmacopeias. This can be attributed to an inner-filter effect.

Acetaminophen↗
PubMed1995

The analysis of aminoglycoside antibiotics by capillary electrophoresis.

The analyses of aminoglycoside antibiotics by capillary electrophoresis utilizing borate complexation and direct UV detection are discussed. Twelve aminoglycosides were studied and separated to demonstrate identification capabilities, with migration time RSDs from 0.21 to 0.44% (n = 6) for individual components. This buffer system permitted the detection of minor impurities such as precursors or closely related fermentation products. Quantification of dihydrostreptomycin and streptomycin was accomplished in 160 mM sodium tetraborate decahydrate with linearity over the range 0.050-1.0 mg ml-1. Determination of the purity of bulk dihydrostreptomycin was possible by the addition of the cationic surfactant myristyltrimethylammonium bromide. This reversed the electroosmotic flow, thereby reversing the migration order, and causing the streptomycin impurity to migrate before the dihydrostreptomycin main peak. Quantification was also demonstrated with the closely related compounds amikacin, bekanamycin, kanamycin A, and tobramycin, using sisomicin as an internal standard. The reproducibility of the method was typically 2-3% over 1 day, and 2% day-to-day. These studies illustrate the use of capillary electrophoresis for the identification and quantification of selected aminoglycosides as potential alternative methods to the assays given by the US Pharmacopeia.

Anti-Bacterial Agents↗
PubMed1995

Comparison of reversed-phase liquid chromatography with colorimetry for analysis of phenolphthalein preparations.

The high-performance liquid chromatography (HPLC) method of the United States Pharmacopeia has been compared with the colorimetric method of the British Pharmacopoeia for the assay of phenolphthalein in various preparations. Results are presented for the linearity, sensitivity and reproducibility of the two methods. The HPLC method was considered to be more convenient for routine analysis of the preparations of phenolphthalein.

Calibration↗
PubMed1996

Interlaboratory study of the analysis of ampicillin by liquid chromatography.

A liquid chromatographic method for the analysis of ampicillin was examined in a collaborative study involving seven laboratories. The method included an isocratic part, which is used in the assay. The isocratic part is similar to the assay method for ampicillin of the US Pharmacopeia XXIII Revision. When the isocratic part is combined with gradient elution, the method is suitable for purity control. Six samples of ampicillin (anhydrous, trihydrate and sodium salt) with varying purity were analysed. The main component and related substances were determined. An analysis of variance proved the absence of consistent laboratory bias. The laboratory-sample interaction was significant. Estimates of the repeatability and reproducibility of the method, expressed as standard deviations of the result of the determination of ampicillin, were calculated to be about 0.9 and 1.1 respectively.

Ampicillin↗
PubMed1996

Microbial sterility testing of oil-formulated bovine somatotropin using Tween 80 dispersion.

The Food and Drug Administration requires that sterile pharmaceutical products be free of viable microorganisms. Sterility testing of pharmaceutical products provides added assurance that the product is sterile. Sterility testing is typically done by inoculating the drug product into microbial growth media followed by visual inspection for growth during incubation for a specified time period. A lack of visual growth indicates that the drug product samples tested were sterile. Formulated Posilac bovine somatotropin consists of protein particles suspended in an oil-based excipient. The product formulation is immiscible in aqueous media due to the excipient's water insolubility and the insolubility of the protein particles at near neutral pH values. Because the formulation is packaged and sold as a sterile product, it is critical that a sensitive microbial sterility test method be used for this key quality test. A sterility test method was developed for Posilac that utilized Tween 80 (i.e. polysorbate 80) as a dispersant. Dispersion of the product using Tween 80 produced a homogeneous suspension of bovine somatotropin particles and oil droplets in the micron size range. The suspension did not appreciably settle out with time, attesting to the homogeneous nature of the mixture. This method was found to be compatible with survival, recovery, and growth from low numbers of the test organisms required by the U.S. Pharmacopeia XXIII as well as from two additional test cultures.

Animals↗
PubMed1990

The development of an enzyme-linked immunosorbent assay for measuring the potency of vaccines containing Clostridium chauvoei antigens.

Current standards (British Pharmacopeia (Veterinary) 1985) for vaccines containing Clostridium chauvoei require a potency test based on a challenge assay in guinea-pigs. Animal welfare and cost considerations favour the development of alternatives. Most veterinary clostridial vaccines are multi component, requiring assays in rabbits to test the potency of components other than C. chauvoei. We describe the application of an ELISA to measure the response to C. chauvoei vaccines in rabbits. The antigen is a sonicated extract of C. chauvoei strain CH4, intended to include a mixture of cellular and soluble antigens. The rabbit response to more than 70 vaccines containing C. chauvoei has been assessed against a reference serum which has been assigned an arbitrary potency of 100 units ml-1. The antibody titres of rabbit sera have been compared with the results of guinea-pig challenge potency tests on the same vaccines. The pass level in the guinea-pig potency test is equivalent to a rabbit ELISA titre of 50 units ml-1.

Animals↗
PubMed1994

Cardiopulmonary bypass: risk management concerns for the anesthesiologist.

Perfusionists have a critically important role in cardiac surgery. Their responsibilities include providing cardiovascular support, maintaining adequate blood flow and blood pressure, maintaining adequate oxygenation, operating suction pumps and other devices, regulating blood temperature, and keeping records. The relationship between perfusionist and anesthesiologist as members of the cardiac surgical team should be one of mutual support. Although many anesthesiologists do not control the pharmacology of perfusion, it is their responsibility to ensure that the perfusionist understands the pharmacopeia being used and to know what the perfusionist is administering. In-depth knowledge of the techniques and practices of cardiopulmonary perfusion is a prerequisite for cardiac anesthesiologists. The future is likely to see an increasingly supportive relationship between anesthesiologists and perfusionists.

Anesthesiology↗
PubMed2004

Analysis of organic volatile impurities in pharmaceutical excipients by static headspace capillary gas chromatography.

A systematic approach for the identification and quantification of organic volatile impurities (OVIs) in pharmaceutical excipients is described. Analytical procedures utilizing static headspace capillary gas chromatography coupled with flame-ionization and MS detection techniques were developed for the analysis of toxic ICH class 1 solvents and US Pharmacopeia OVIs at sub-ppm levels, and commonly used organic solvents in a wide range of concentrations. Chromatographic conditions and headspace parameters for the methods were optimized for separation, sensitivity, and speed. The proposed methodologies were demonstrated to be selective, accurate, and reproducible, and were successfully applied to the rapid screening of OVIs in typical excipients.

Chromatography, Gas↗
PubMed2004

Chromatographic multivariate quality control of pharmaceuticals giving strongly overlapped peaks based on the chromatogram profile.

In the present paper, the simultaneous quantification of two analytes showing strongly overlapped chromatographic peaks (alpha = 1.02), under the assumption that both available equipment and training of the laboratory staff are basic, is studied. A pharmaceutical preparation (Mutabase) containing two drugs of similar physicochemical properties (amitriptyline and perphenazine) is selected as case of study. The assays are carried out under realistic working conditions (i.e. routine testing laboratories). Uncertainty considerations are introduced in the study. A partial least squares model is directly applied to the chromatographic data (with no previous signal transformation) to perform quality control of the pharmaceutical formulation. Under the adequate protocol, the relative error in prediction of analytes is within the tolerances found in the pharmacopeia (10%). For spiked samples simulating formulation mistakes, the errors found have the same magnitude and sign to those provoked.

Multivariate Analysis↗
PubMed2004

Multiple level C in vitro/in vivo correlation of dissolution profiles of two L-thyroxine tablets with pharmacokinetics data obtained from patients treated for hypothyroidism.

In a previous study aimed to compare the bioavailability of two levothyroxine tablets, we found a good relation between their pharmacokinetics parameters and dissolution profiles, employing the USP dissolution conditions in use at that time (24th edition). Despite the formulations were considered bioequivalent, the test product presented values of AUC and concentrations at steady-state significantly lower (about 10%) than the reference ones. The purpose of the present study was to evaluate if the actual pharmacopeial conditions (with alterations introduced in the first supplement of USP 24) would also allow a good correlation between bioavailability and dissolution data. The partial AUCs were correlated with cumulative levothyroxine amount dissolved at three different times, for each dissolution condition. Employing the old method, test tablets had a slower dissolution rate than the reference ones, resulting in a quite good multiple level C in vitro/in vivo (IVIV) correlation. On the other hand, the very fast dissolution profiles obtained in the actual condition lead to a worse IVIV correlation. Present work indicates that the mild conditions proposed in the older US Pharmacopeia were better than the actual in order to discriminate dissolution profiles of levothyroxine tablets which present subtle, but significant, differences in their pattern of absorption.

Area Under Curve↗
PubMed2006

Development and optimization of a novel sustained-release dextran tablet formulation for propranolol hydrochloride.

A novel oral controlled delivery system for propranolol hydrochloride (PPL) was developed and optimized. The in vitro dissolution profiles of sustained-release matrix tablets of racemic PPL were determined and compared with the United States Pharmacopeia (USP) tolerance specifications for Propranolol Hydrochloride Extended-Release Capsules. The influence of matrix forming agents (native dextran, hydroxypropyl methylcellulose (HPMC), cetyl alcohol) and binary mixtures of them on PPL release in vitro was investigated. A central composite design was applied to the optimization of a sustained-release tablet formulation. The sustained-release matrix tablets with good physical, mechanical and technological properties were obtained with a matrix excipient:PPL ratio of 60:40 (w/w), with a dextran:HPMC ratio of 4:1 (w/w) and with a cetyl alcohol amount of 15% (w/w). A comparative kinetic study of the present matrix tablets and commercial SUMIAL RETARD capsules (Spain) was established. The value for the similarity factor (f(2)=69.6) suggested that the dissolution profile of the present two sustained-release oral dosage forms are similar. Higuchi (diffusion) and Hixon-Crowell (erosion) kinetic profiles were achieved and this codependent mechanism of drug release was established.

Capsules↗
PubMed2006

Elevated temperature accelerated release testing of PLGA microspheres.

Drug release from four different poly(lactic-co-glycolic) acid (PLGA) microsphere formulations was evaluated under "real-time" (37 degrees C) and accelerated release testing conditions of elevated temperature (45, 53, 60 and 70 degrees C) and increase in flow rate (4-35 ml/min) using United States Pharmacopeia (USP) apparatus 4. Formulation 5 K (composed of low Mw PLGA) exhibited diffusion-controlled kinetics in "real-time". Whereas, formulations 25 K, 28 K and 70 K (composed of medium and high Mw PLGA) followed erosion-controlled kinetics at 37 degrees C. Temperature-induced degradation of the microspheres was studied by monitoring drug release rates, change in molecular weight and morphological changes. Drug release rates at elevated temperature were used to predict "real-time" release applying the Arrhenius equation. The energy of activation for dexamethasone release from PLGA microspheres was calculated as 19.14 kcal/mol. Molecular weight change measured by gel permeation chromatography followed first order kinetics for both "real-time" and accelerated release. All four formulations exhibited morphological changes (such as surface pore closing and geometry change) at elevated temperature with consequent reduction in burst release.

Chemistry, Pharmaceutical↗
PubMed2004

The role of weeds as sources of pharmaceuticals.

Primary tropical forest is generally considered to be the most likely habitat to discover new pharmaceuticals, due to high biodiversity and endemism. However, many indigenous groups rely on non-forested disturbed environments for medicinal plants. An ethnobotanical approach to drug discovery suggests that these disturbed environments may also harbor potentially useful medicinal compounds. Despite the neglect by current researchers to conduct drug discovery in disturbed environments, many source plants for modern pharmaceuticals thrive in disturbed areas. An analysis of the 101 plant species from which 119 contemporary pharmaceuticals are derived shows that at least 36 of these plants are considered weeds (Chi 2 = 343.34, P<0.0001). These results are an order of magnitude higher than what would be predicted by random occurrence of weeds in the modern pharmacopeia. Biochemical evidence based on literature is presented to explain this occurrence. This finding suggests that disturbed habitats may be important areas to search for novel compounds in drug discovery.

Ethnobotany↗