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At least 703 records · Page 39Linked to original sources
PubMed2000

A search for natural bioactive compounds in Bolivia through a multidisciplinary approach. Part IV. Is a new haem polymerisation inhibition test pertinent for the detection of antimalarial natural products?

The search for new antimalarial agents in plant crude extracts using traditional screening tests is time-consuming and expensive. New in vitro alternative techniques, based on specific metabolic or enzymatic process, have recently been developed to circumvent testing of antimalarial activity in parasite culture. The haem polymerisation inhibition test (HPIA) was proposed as a possible routine in vitro assay for the detection of antimalarial activity in natural products. A total of 178 plant extracts from the Pharmacopeia of the Bolivian ethnia Tacana, were screened for their ability to inhibit the polymerisation of haematin. Five extracts from Aloysia virgata (Ruíz & Pavón) A.L. Jussieu (Verbenaceae), Bixa orellana L. (Bixaceae), Caesalpinia pluviosa D.C. (Caesalpiniaceae), Mascagnia stannea (Griseb) Nied. (Malpighiaceae) and Trichilia pleenea (Adr. Jussieu) (Meliaceae) demonstrated more than 70% inhibition of haematin polymerisation at 2.5 mg/ml. The extracts were also tested for antimalarial activity in culture against F32 strain (chloroquine-sensitive) and D2 strain (chloroquine-resistant) of Plasmodium falciparum and in vivo against P. berghei. The extract from Caesalpinia pluviosa was the only one that showed activity in HPIA and in the classical test in culture. The accuracy and pertinence of HPIA, applied to natural products is discussed.

Animals↗
PubMed2001

Should we be concerned about herbal remedies.

During the latter part of this century the practice of herbalism has become mainstream throughout the world. This is due in part to the recognition of the value of traditional medical systems, particularly of Asian origin, and the identification of medicinal plants from indigenous pharmacopeias that have been shown to have significant healing power, either in their natural state or as the source of new pharmaceuticals. Generally these formulations are considered moderate in efficacy and thus less toxic than most pharmaceutical agents. In the Western world, in particular, the developing concept that 'natural' is better than 'chemical' or 'synthetic' has led to the evolution of Neo-Western herbalism that is the basis of an ever expanding industry. In the US, often guised as food, or food supplements, known as nutriceuticals, these formulations are readily available for those that wish to self-medicate. Within this system, in particular, are plants that lack ethnomedical verification of efficacy or safety. Unfortunately there is no universal regulatory system in place that insures that any of these plant remedies are what they say they are, do what is claimed, or most importantly are safe. Data will be presented in this context, outlining how adulteration, inappropriate formulation, or lack of understanding of plant and drug interactions have led to adverse reactions that are sometimes life-threatening or lethal.

Female↗
PubMed2000

Drugs in prehistory: chemical analysis of ancient human hair.

Concern about drug abuse in modern populations has led to the development of specific methods for identification of cocaine, opiates and cannabis in human hair. Drug use in prehistory can provide indirect evidence of interpopulational contact and social stratification. This paper reports drug evaluation in nineteen ancient hair samples from archaeological sites in northern Chile. Each sample was tested for the presence of traces of cocaine, opiates and cannabis, in order to establish a standard methodology for studies of drug use among prehistoric groups. Although results are negative, this absence of evidence could be due to two main causes: (1) the individuals evaluated did not use any drugs, which does not mean that other members of their cultural group did, or (2) the wide range of known drugs studied did not consider some group specific drugs, derived from local or imported plants, thus meaning that a greater drug range must be tested. In any case, our study confirms that drug testing in prehistoric samples is viable. However, in order to determine what kind of substances were used in prehistoric times new patterns that incorporate all drugs which are not part of the western pharmacopeia must be created. Finally, a methodology for the study of drug use among prehistoric groups using ancient hair samples is described.

Cannabinoids↗
PubMed2001

A stability-indicating HPLC assay method for budesonide.

The official (European) pharmacopeial assay for budesonide was found to be non-specific and non-stability-indicating when used to qualify several batches of pharmaceutical grade drug substance from different sources. In contrast, the most widely cited HPLC method in the literature was found to be specific and stability-indicating with respect to drug substance stored in the dry state. However, that method failed the pharmacopeia's assay system suitability requirements because of peak tailing. Moreover, it was unable to detect or resolve two major degradation products which resulted from drug storage in non-aqueous solution. A new stability-indicating HPLC method described here overcomes these problems. This method used a Hypersil C18 column with a mobile phase consisting of ethanol-acetonitrile phosphate buffer (pH 3.4; 25.6 mM) (2:30:68, v/v/v), a flow rate of 1.5 ml/min and UV detection at 240 nm. The purity of budesonide EP and its impurity profile (related substances) were tested using the new assay method, and the results compared to those from the two other methods described above. Solid-state and solution stressed stability samples were used to evaluate all methods. Using the novel method, the epimers of budesonide. their related impurities and degradation products were separated successfully. Validation studies demonstrated that the novel method possessed a linear UV response, good system precision and accuracy, high sensitivity and specificity for budesonide. The novel method will be used for future studies of budesonide's degradation kinetics.

Anti-Inflammatory Agents↗
PubMed2001

Development and validation of a stability indicating HPLC assay method for cyclosporine in cyclosporine oral solution USP.

The suitability of the United States Pharmacopeia (USP) assay method for analysing stressed samples of cyclosporine oral solution USP was evaluated for stability samples by analyzing cyclosporine oral solution after acid, alkali, hydrogen peroxide, heat and light treatment. Some of the degradants generated during stress testing, as well as dihydrocyclosporine A, which is a known degradant of cyclosporine A, were not adequately resolved from the cyclosporine peak and mobile phase adjustments did not improve the resolution. In addition, isocyclosporine A, another known degradant of cyclosporine, could not be quantitated as it was eluting too early with the system peaks. Therefore, a binary gradient, reverse phase, stability indicating, HPLC method for the assay of cyclosporine in cyclosporine oral solution USP has been developed and validated. Analysis of degraded samples showed that the cyclosporine A eluted as a spectrally pure peak resolved from its degradation products.

Administration, Oral↗
PubMed2002

Preparative resolution of drug racemates to study the chiroptical properties of their enantiomers.

The present work is focused on the resolution of ten racemates, in order to study their chiroptical properties and to test the validity of the requirement specified in the European Pharmacopeia (EP) for demonstrating that a drug entity is a racemate. This work shows that the optical purity of enantiomers and non racemic mixtures of a number of compounds can be determined more accurately by circular dichroic (CD) spectroscopy than by a measurement of the angle of rotation (AoR), the EP requirement. Using only the AoR, some of the racemates could not be distinguished from the enantiomers. CD spectroscopy or chiral chromatography should, therefore, be the technique of choice in the determination of optical purity of a chiral compound, especially for those exhibiting low AoR.

Chromatography↗
PubMed2002

Spectrofluorometric determination of naproxen in tablets.

A rapid, selective, sensitive and simple fluorescence method was developed for the direct determination of naproxen in tablets. The tablets were triturated, dissolved in either NH(3) or NaOH solution, sonicated, filtered and then direct fluorescence emission was read at 353 nm (exciting at 271 nm). In order to validate the method the results were compared with those obtained by the USP XXIV NF 19 Pharmacopeia reference method (high performance liquid chromatography). The slope, intercept and variances which are associated with the regression coefficient calculated with bivariate least square (BLS) regression indicate that both methods are statistically comparable. The recoveries were excellent, except in tablets containing the antibiotic tetracycline. In this latter case a correction procedure is necessary.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Modified resolution factor for asymmetrical peaks in chromatographic separation.

The quality of separation is measured by resolution factor (R(s)) between adjacent peaks. The current United States Pharmacopeia (USP) method for R(s) calculation assumes symmetrical peak shapes. In practice, perfectly symmetrical peaks are rarely encountered. The goal of this study was to correct the inaccuracy due to peak asymmetry by using a new formula for R(s) calculation. Peak tailing factor was incorporated into the formula for the calculation of R(s) to correct for the peak asymmetry. The resulting modified formula was compared with USP formula using simulated peaks and actual peaks. Through mathematical derivation, the modified R(s) was expressed as: R=[2(t(2)+W(2)/2(1-1/TF(2))-t(1)-W(1)/2(1-1/TF(1)))]/W(1)+W(2) where t(1) and t(2) are the retention times of two peaks, W(1) and W(2) are peak widths at baseline, TF(1) and TF(2) are USP tailing factors. All parameters used in the formula are available from commercial data analysis software. Comparisons of modified R(s) to USP R(s) showed that the modified R(s) provided a more accurate measure of peak separation at the baseline level.

Chromatography, High Pressure Liquid↗
PubMed2003

Development and validation of an UV derivative spectrophotometric determination of Losartan potassium in tablets.

Development and validation of an analytical UV derivative spectrophotometric method to quantify Losartan potassium used as a single active principle in pharmaceutical forms were done. Pharmacopeias have not yet provided an official method for its quantification. A study was carried out of all the parameters established by USP XXIV to validate an analytical method for a solid pharmaceutical form, i.e. linearity, range, accuracy, precision and specificity. All these parameters were found in accordance with the acceptance criteria of Comité de Guías Oficiales de Validación de la Dirección General de Control de Insumos para la Salud de México. Based on the spectrophotometric characteristics of Losartan potassium, a signal at 234 nm of the first derivative spectrum (1D234) was found adequate for quantification. The linearity between signal 1D234 and concentration of Losartan potassium in the range of 4.00-6.00 mg l(-1) in aqueous solutions presents a square correlation coefficient (r2) of 0.9938. The mean recovery percentage was 100.7+/-1.1% and the precision expressed as relative standard deviation (R.S.D.) 0.88%. In addition, the proposed method is simple, easy to apply, low-cost, does not use polluting reagents and requires relatively inexpensive instruments. Then, it is a good alternative to existing methods for determining Losartan potassium in tablets provided that the pharmaceutical dosage form does not contain hydrochlorothiazide as second drug.

Antihypertensive Agents↗
PubMed1997

Effect of water content in perchloric acid on the non-aqueous potentiometric titration of nitrogen-containing compounds.

In the United States Pharmacopeia (USP), 0.1 N perchloric acid in acetic acid volumetric solution (hereafter HClO4 VS) used for non-aqueous titration has specified a water content between 0.02 and 0.05%. Preparing this titrant with such a narrow range of water content is very time consuming, precludes the use of commercially available titrants, and, consequently, prompted an investigation to try and expand the range up to 0.5%. In this study, the titrimetric results obtained using HClO4 VS containing more water were very close to those obtained using the USP specified titrants. A maximum assay difference of 0.7% in the titrations of three selected nitrogen-containing compounds, clonidine hydrochloride, dipyridamole, and adenosine were observed. The titrimetric results obtained using these titrants were also precise with RSDs of not more than 0.4%. Therefore, a wider range of water content in HClO4 VS between 0.02 and 0.5% is suggested for the USP potentiometric titration of nitrogen-containing compounds.

Indicators and Reagents↗
PubMed1999

Nested designs in ruggedness testing.

Nested designs were performed in order to execute a ruggedness test according to the United States Pharmacopeia definition for ruggedness, in which mainly non-procedure related factors are examined. Several nested designs have been executed on a high performance liquid chromatography assay to determine tetracycline and related substances in bulk samples of tetracycline. Factors such as different laboratories, analysts, instruments, columns, days and batches were examined. The interpretation methods described in the literature were found to cause problems. In these methods the variances of the examined factors are estimated from the calculated mean square values and from the equation for the expected mean squares. Very frequently, negative variance estimates were obtained. Their absolute values were found to be dependent on the influence of the factor examined below it in the design, on the examined response. Therefore an alternative interpretation method for nested designs, based on pooled variances, was proposed and found to be appropriate to use for ruggedness testing purposes. Both approaches, the one from the literature and the one proposed here, were tested on simulated data coming from a nested design with four factors and on the experimentally measured data.

Analysis of Variance↗
PubMed2004

Simulation of air-bag impact on an eye with transsclerally fixated posterior chamber intraocular lens using finite element analysis.

PURPOSE: To determine the physical and mechanical conditions of an impacting air bag that would rupture an eye with a transsclerally fixated posterior chamber intraocular lens (IOL). SETTING: Numerical simulation study on a computer. METHODS: Simulations in a model human eye were performed with a computer using the finite element analysis program PAM-CRASH (Nihon ESI). The air bag was set to impact the surface of an eye with a transsclerally fixated posterior chamber IOL at various velocities. The tensile force limit of a 10-1 polypropylene suture was assumed to be 0.16 N, which is specified in the U.S. Pharmacopeia XXII. RESULTS: At the lowest velocity of 20.0 m/s, 10-0 polypropylene sutures were not likely to break. Sutures fixating the IOL might break and a corneoscleral incision was likely to open after 0.3 second at the medium impacting velocity (30 m/s). Suture rupture was very likely at the highest velocity (40 m/s) since the tensile force on the sutures continuously exceeded the breaking force after the impact. CONCLUSIONS: In an eye with a transsclerally fixated posterior chamber IOL, severe ocular trauma can be caused by an air bag at high velocity. Small individuals such as elderly women are at greater risk for air-bag ocular injury. Further research on modifying air-bag design and deployment is important to minimize the risk for ocular injury.

Air Bags↗
PubMed2000

Radiolabelled biodegradable microspheres for lung imaging.

The effect on lung accumulation of modifying the surface compositions of (99m)Tc poly(lactide-co-glycolide) (PLGA) and (99m)Tc poly(ethylene glycol)-poly(lactide-co-glycolide) (PEG-PLGA) microspheres with different surfactants was assessed after intravenous injection into rats. Microspheres were prepared with PLGA or PEG-PLGA by the emulsion solvent evaporation method using polyvinyl alcohol (PVA), polyethylene glycol (PEG), albumin (BSA) or poloxamer 188 as surfactant, in the external aqueous phase. Commercial human albumin microspheres (Sferotec((R)), HAM) were used as reference. According to the European Pharmacopeia, >80% of (99m)Tc-HAM in the size range 10-50 microm, must be accumulated in the lung 15 min after intravenous administration. By modifying the surfactant, the resulting lung accumulation was 99% for (99m)Tc-HAM, and more than 50% for PLGA microspheres prepared with poloxamer 188 (1 and 4%), reaching 67% with 8% Poloxamer 188 and around 30-39% for PLGA and PEG-PLGA microspheres prepared with the other surfactants. PLGA microspheres made with 8% poloxamer 188 gave good quality lung images under a gamma camera for the first few minutes, subsequently liver radioactivity masked lung images.

Animals↗
PubMed1999

In vitro/in vivo correlations of dissolution data of carbamazepine immediate release tablets with pharmacokinetic data obtained in healthy volunteers.

The aim of the study was to select a dissolution test method for carbamazepine (CBZ) immediate release tablets, giving the best in vitro/in vivo correlations (IVIVC) and to determine the potential of this method as an estimate for bioequivalence testing. Four 200 mg CBZ products which are sold on the Dutch market, covering the innovator and three generic products, were selected. They had been tested in a randomised, fourway cross-over bioavailability study in healthy volunteers. Their dissolution rate behaviour in vitro was investigated in two dissolution media: (1) 1% sodium lauryl sulphate in water (SLS), in accordance with the United States Pharmacopeia (USP); (2) 0.1 mol/l Hydrochloric acid in water (HC). In the bioavailability study these products had shown no large differences in the extent of absorption (AUC(0-infinity);) but large differences in absorption rate. The products now also showed large differences in dissolution rate in vitro in both dissolution media, the rank order being the same as for the absorption rate. It was concluded that the absorption rate in vivo depends on the dissolution rate in vivo. 'Level C' IVIVC according to the USP were optimised by plotting percentages dissolved on selected time points (D values) or their reciprocals (1/D values), against several pharmacokinetic parameters primarily related to the absorption phase and against AUC(0-infinity). In this way for each IVIVC the optimum D or 1/D value, was calculated. For both media no meaningful IVIVC were obtained with AUC(0-infinity), but favourable IVIVC were obtained with the parameters primarily related to the absorption phase. In the bioavailability study indicated above it was found that, among the pharmacokinetic characteristics primarily related to the absorption phase, C(max) is the most promising in expressing rate of absorption in bioequivalence testing in single dose studies with CBZ immediate release tablets. Consequently, C(max) was selected for expressing rate of absorption. The most favourable IVIVC were obtained with D(20) in SLS versus C(max). From this IVIVC and the requirements for bioequivalence (AUC(0-infinity): 0.8-1.25 and C(max) : 0.75-1.35; 90% confidence interval), a specification for dissolution testing in SLS was calculated as follows: 'after 20 minutes, 34-99% dissolved'. Owing to the fact that the rate of absorption in vivo depends on i.a. the dissolution rate in vivo, it can be concluded that with this specification bioequivalence with respect to both rate of absorption and extent of absorption is ensured. As this specification is comparable with the USP specification: 'not less than 75% dissolved after 1 h', it is concluded that the USP specification is suitable to ensure bioequivalence of CBZ immediate release tablets.

Anticonvulsants↗
PubMed1998

Pharmacopeial harmonization in biotechnology.

There has been progress in the pharmacopeial harmonization initiative among the United States Pharmacopeia (USP), the European Pharmacopoeia and the Japanese Pharmacopoeia. Monographs on excipients and on biotechnology-derived products, as well as for General Chapters are progressing through the various stages of the harmonization process. An additional initiative, Concordance of Foreign Pharmacopeial Tests and Assays has been proposed by the USP.

Biotechnology↗
PubMedDate not supplied

Storage temperatures of medications on an air medical helicopter.

INTRODUCTION: The safety and efficacy of medications stored on air medical helicopters may be adversely affected by extreme temperatures. The purpose of this study was to determine whether temperatures inside an air medical helicopter drug box were within the U.S. Pharmacopeia recommendations for controlled room temperature. This is defined as a temperature between 15 degrees and 30 degrees C (59 degrees and 86 degrees F) with a mean kinetic temperature of less than 25 degrees C (77 degrees F). An additional goal was to determine whether time/temperature indicator labels can reliably monitor mean kinetic temperatures. METHODS: Temperatures were monitored with miniature electronic temperature recorders and color-changing time/temperature indicator labels. RESULTS: The mean kinetic temperatures for the summer and winter periods were 25.1 degrees C (77.2 degrees F) and 12.7 degrees C (54.8 degrees F), respectively. In the summer, the electronic recorders logged temperatures exceeding 25 degrees C (59 degrees F) 37% of the time and more than 30 degrees C (86 degrees F) 6% of the time. In the winter, temperatures less than 15 degrees C (59 degrees F) were recorded 83% of the time. The mean kinetic temperatures obtained from the electronic recorder and the time/temperature indicator labels differed by less than 0.7 degree C (1.3 degrees F). The results show that medications on an air medical helicopter are subject to temperatures out of the recommended range and that time/temperature indicator labels can reliably monitor mean kinetic temperatures.

Air Ambulances↗
PubMed1998

Knot properties of alternating sliding knots with different patterns in comparison to alternating and simple sliding knots.

This study attempts to compare the alternating sliding knots with different patterns with the alternating and simple sliding knots. Silk and nylon sutures of 2-0 and 4-0 United States Pharmacopeia (USP) sizes were mechanically tested. The values of knot holding capacities (KHCs) varied depending on knot configuration, suture material, and size. The parallel alternating knot with different patterns showed a high KHC for silk suture of both sizes. For nylon, the alternating knots with different patterns were comparable to the simple sliding knots. When we compared silk with nylon in knots with different patterns we observed the following. For size 2-0 loops, the nonidentical knot of nylon was higher in KHC than that of silk, and the parallel knot of silk was higher in KHC than that of nylon. Loops of 4-0 showed higher KHCs for the parallel knot in nylon than in silk but similar values for both materials with the nonidentical knot. The parallel alternating knot with different patterns was the most efficient for nylon 4-0. The silk loops had good efficiencies for both sizes. The silk suture knots were all reliable. The nylon suture showed unreliability for the parallel and alternating nonidentical knots of both sizes and the alternating parallel knot in 2-0 suture. The results section discusses the physical structure and suture dimension. This study did not prove that the strength of the knot increases with complexity.

Humans↗
PubMed2000

What's in a name? Lessening the confusion over drug names.

Confusion over the similarity of drug names, either written or spoken, accounts for approximately one-quarter of all reports to the U.S. Pharmacopeia (USP) Medication Errors Reporting (MER) program. This issue involves confusion between similar brand names, similar generic names, and similar brand and generic names. Such confusion is compounded by illegible handwriting, incomplete knowledge of drug names, newly available products, similar packaging or labeling, and incorrect selection of a similar name from a computerized product list.

Drug Therapy↗