bluuebunny/crossref_metadata_2025_split huggingface dataset:
The kinetics of crystallization of potassium bromide from aqueous solution
Authors: RIDGWAY K , AULTON M E 
Published: April 2011

Abstract
The densities of aqueous solutions of potassium bromide have been determined as a function of concentration and temperature up to saturation at temperatures between 10 and 50°. The saturation line and nucleation were studied, over the same temperature range, in a circulatory crystallizer with continuous concentration monitoring. Small quantities of seed crystals were grown under different degrees of supersaturation and at different temperatures, so that the mass transfer coefficients and the activation energy for deposition from solution could be measured. The activation energy of the crystallization process was 100·9 kJ mol−1, indicating that the rate-determining step was the incorporation of KBr on to the crystal lattice. Rapidly-grown crystals might thus be expected to be softer, and this proved to be so.
Alkaloids from two Nigerian species of Fagara
Authors: FISH F , WATERMAN P G 
Published: April 2011

Abstract
Skimmianine, chelerythrine, nitidine, 1-hydroxy-2,3-dimethoxy-10-methylacridan-9-one and 1-hydroxy-3-methoxy-10-methylacridan-9-one have been isolated from the root and stem barks of Fagara rubescens. Using thin-layer chromatography and high voltage electrophoresis, a comparison of the chloroform-insoluble quaternary alkaloids of this species has been made with those from F. leprieurii. The distribution of the alkaloids within the barks and the chemotaxonomic significance of the alkaloids in the two species are discussed.
The in vitro evaluation of gelatin coacervate microcapsules
Authors: NIXON J R , WALKER S E 
Published: April 2011

Abstract
Microcapsules of sulphadiazine have been prepared by the simple gelatin coacervation technique, using sodium sulphate as coacervating agent. The free flowing microcapsular material was hardened with formalin. There is no direct relation between particle size and sulphadiazine concentration nor between different starting gelatin percentages. The effects on size of hardening time, temperature and sampling time are small. In vitro dissolution studies show that first order release characteristics are exhibited by all the hardened materials. Temperature and pH effects indicate the dissolution of the sulphadiazine itself to be the controlling step rather than the rate of diffusion through the microcapsule wall.
Further studies on the effect of additives on the release of drug from hard gelatin capsules
Authors: NEWTON J M , ROWLEY G , TÖRNBLOM J-F V 
Published: April 2011

Abstract
An experiment based on a 33 design has been undertaken to establish the effect on drug release from capsules produced by adding lactose (0, 10 and 50%), magnesium stearate (0, 1 and 5%), and sodium lauryl sulphate (0, 1 and 10%) to a 76–105μm particle size fraction of ethinamate filled into capsules at a high and low packing density. Statistical analysis of the results indicated the presence of 2nd order interaction at all time intervals and for both sets of capsule fill weights. This signifies that the effect produced by each additive is dependent on the presence and the level of the other two additives. The interaction limits the conclusions that can be drawn about the main factors of diluent, lubricant and wetting agent, but the indications are that (a) 10% diluent reduces drug release, whereas 50% produces enhanced release; (b) the presence of 1% sodium lauryl sulphate is sufficient to enhance drug release; (c) the additive effects are independent of the capsule packing density.
Hydrophobic bonding in soap-stabilized emulsions
Authors: DAVIS STANLEY S 
Published: April 2011

Abstract
The rheological properties of emulsions stabilized by potassium laurate have been measured at different temperatures and in the presence of urea to assess the validity of the concept of aggregation through hydrophobic interactions. The elasticity of the systems, as measured by a Rheogoniometer, increased with increased temperature and decreased with added urea. These results are entirely consistent with hydrophobic bonding. The mechanism of bonding is discussed in terms of interfacial hydrolysis, complex condensed films of acid soap, and polymolecular adsorption of surfactant at the oil-water interface.
Digital filters in the evaluation of titration curves
Authors: PERKS F , GLENN A L 
Published: April 2011

Abstract
The shape of a titration curve contains useful information, which may be extracted in terms of orthogonal polynomial coefficients. In this way, it is possible to (i) distinguish a monobasic acid from a polybasic acid, having groups of closely similar strength; (ii) detect acid-base impurities in acids and bases, and (iii) study medium effects. The choice of polynomial, range, number of points and experimental conditions are discussed. Using twelve point polynomials and equipment of modest performance, the Pi coefficient (for the central half of a monobasic acid titration curve) can be measured with a relative standard deviation of 0·58.
Computer analysis of the relation between tablet strength and compaction pressure
Authors: NEWTON J M , ROWLEY G , FELL J T , PEACOCK D G , RIDGWAY K 
Published: April 2011

Abstract
The load necessary to fracture lactose monohydrate tablets under diametral compression has been determined using an Instron physical testing instrument, so that true tensile failure was obtained in all cases, leading to improved reproducibility. Four ranges of tablet thickness were examined at 12·7 mm diameter. All tablets gave a linear increase of breaking load with compaction pressure up to 310 MN/m2. Expressing the tablet strength as the breaking load gave a separate regression line for each range of tablet thickness, whereas the use of tensile strength provided a common regression line, within given statistical limits, for all but the lowest range of tablet thickness. The fact that such a correlation is possible shows that the tensile strength is a property of the “as compacted” material and provides a new and useful parameter to maintain constancy of properties when tablet size is changed.
The actions of histamine and prostaglandins F2α and E2 on pulmonary vascular resistance of the lung of the guinea-pig
Authors: OKPAKO D T 
Published: April 2011

Abstract
In the guinea-pig isolated perfused lung, prostaglandin F2α (PGF2α) and histamine increased, and prostaglandin E2 (PGE2) decreased, resistance to fluid flow. PGF2α and histamine caused contractions of the pulmonary artery circular muscle preparation while PGE2 inhibited contractions caused by other agonists. It was concluded that the changes in resistance to fluid flow caused by the three agents was partly or wholly due to their direct action on pulmonary vascular tissue. Mepyramine abolished the pressor response to histamine but had no effect on the pressor response to PGF2α. Furthermore, there was no evidence of the involvement of adrenergic mechanisms in the action of the prostaglandins. It is suggested that PGF2α probably plays a role in the pulmonary vasoconstriction caused by anaphylaxis in guinea-pigs pretreated with mepyramine.
The effect of morphine pretreatment on the sensitivity of mouse and guinea-pig ileum to acetylcholine and to morphine
Authors: HAYCOCK VIVIEN K , REES J M H 
Published: April 2011

Abstract
Guinea-pigs and mice were subjected to morphine pretreatment for at least 14 days culminating in subcutaneous injections of 1 g/kg daily in 2 divided doses. In mice, tolerance to the effects of morphine on gastrointestinal propulsion had developed by the end of the pretreatment course. The sensitivity to acetylcholine of the ilia from pretreated animals and the effects of morphine on transmural stimulation were compared with the ilia from normal animals. Ilia from pretreated guinea-pigs were marginally more sensitive to frequency of stimulation but significantly less sensitive to the depressant effect of morphine than ilia from normal animals. There was no significant difference in the sensitivity to acetylcholine. There was a highly significant decrease in sensitivity to morphine of ilia from pretreated mice, but this also was not associated with any alteration in sensitivity to acetylcholine. It is concluded that on the isolated ileum preparation the development of tolerance to morphine is not associated with an increased sensitivity to the transmitter whose release morphine inhibits.
Observations on the interactions between desipramine and reserpine on adrenergic transmission in the rat
Authors: COTILLO P , BONACCORSI A 
Published: April 2011

Abstract
The time course of the impairment of the adrenergic transmission induced by reserpine has been examined on the inferior eyelid of the rat pretreated with desipramine. Desipramine given before reserpine is able to counteract, in a dose-dependent manner, the impairment induced in the first hours after reserpine. On the contrary, desipramine has only a limited effect, not dose-dependent, when given after the reserpine treatment.
Pharmacokinetics of absorption, distribution and elimination of fenfluramine and its main metabolite in man
Authors: BECKETT A H , SALMON J A 
Published: April 2011

Abstract
Previously reported data (Beckett & Brookes, 1967) for the excretion of (±)-fenfluramine and its main metabolite, norfenfluramine, have been examined pharmacokinetically using an analogue computer. A three compartment open model was proposed to simulate the biological processes with one peripheral compartment rapidly equilibrating with the central compartment and the second (tissue) compartment only slowly attaining equilibrium. Good agreement between experimental and computed data was obtained, although marked inter-subject variation was recorded. This was attributed to inter-subject differences in the three body compartments. Differences between the pharmacokinetic parameters obtained after oral and intravenous administration of fenfluramine indicated that the drug was significantly N-dealkylated in the intestine or on a first-pass through the liver.
Partition coefficients of salicylic acid between water and the micelles of some non-ionic surfactants
Authors: COLLETT J H , WITHINGTON R 
Published: April 2011

Abstract
Partition coefficients of ionized and unionized salicylic acid molecules between water and the micelles of several non-ionic surfactants have been determined. Those of unionized molecules decreased with decreasing length of the surfactant alkyl chain and with increasing length of the surfactant polyoxyethylene chain. Ionized salicylic acid partitioned to a significant extent only into those surfactants having more than approximately 44 oxyethylene units in their hydrophile. The findings are discussed in terms of their biopharmaceutical significance.
Relation between cation and lipid content of cell walls of Pseudomonas aeruginosa, Proteus vulgaris and Klebsiella aerogenes and their sensitivity to polymyxin B and other antibacterial agents
Authors: BROWN M R W , WOOD SANDRA M 
Published: April 2011

Abstract
Sensitivity to polymyxin correlated with amount of phospholipid in wall fractions of Pseudomonas aeruginosa, Proteus vulgaris and Klebsiella aerogenes and to a lesser extent with wall cation. The affinity of polymyxin for phospholipid from P. vulgaris and P. aeruginosa was the same.
Scopolia lurida, Dunal; the structure of the leaves and stem
Authors: MILLS DAVID E , JACKSON BETTY P 
Published: April 2011

Abstract
The aerial parts of Scopolia lurida contain large quantities of tropane alkaloids and are a possible source of hyoscyamine and hyoscine. The leaves and stems are very similar to those of Atropa belladonna but they can be distinguished by certain microscopical characters; these include the presence of branched covering trichomes on the leaves and stems of Scopolia lurida and the absence of idioblasts containing microsphenoidal crystals of calcium oxalate from the leaf lamina.
Adaptation to the natriuretic actions of hydrochlorothiazide, frusemide and amiloride, by rats
Authors: ILETT K F , LOCKETT MARY F 
Published: April 2011

Abstract
Rats treated thrice daily with maximally natriuretic doses of amiloride or of frusemide showed a markedly diminished natriuretic response (adapted) by the third day and complete adaptation to hydrochlorothiazide by the fifth day of treatment. Normal rats supplied with 0.7 % NaCI as drinking fluid and adrenalectomized rats maintained by either a high salt intake or by injections of doca could not adapt to the natriuretic effects of hydrochlorothiazide. There was no adaptation to the effects of these diuretics on K+ excretion. Treatment of rats for eight successive days with amiloride, frusemide or hydrochlorothiazide caused significant elevation of the juxtaglomerular index and hyperactivity in the zona glomerulosa of the adrenal. Treatment for eight days with spironolactone did not produce these changes. The in vitro production of aldosterone was significantly increased in glands taken from animals pretreated for eight days with hydrochlorothiazide: spironolactone did not influence this synthesis. Plasma concentrations of corticosterone were unaffected by eight days of exposure to hydrochlorothiazide, were raised by this exposure to frusemide and were lowered by amiloride. It is considered that the reninangiotensin-aldosterone system plays a rôle in adaptation, over days, to the natriuretic effects of sulphonamide and probably other natriuretic diuretics, in the rat.
Effect of β-adrenoceptor antagonists on the decline of the chronotropic response to isoprenaline
Authors: FENYVESI T , GEORGE C F , DOLLERY C T 
Published: April 2011

Abstract
The effect of three β-adrenoceptor antagonists (propranolol, practolol and H 35/25*) have been investigated on the decline of the tachycardia produced by intravenous doses of isoprenaline. Propranolol (0.5 mg/kg laevo-isomer) caused a significant increase in the rate of decline from 17.2 to 36.5 beats/min. Practolol (2 mg/kg), H 35/25 (2 mg/kg) and the combination of the two did not influence the rate of decline. Only propranolol caused a change in the slope of the isoprenaline heart rate dose-response curve; the observed increase of this slope is the probable cause of the change in rate of decline of the heart rate response.
Physicochemical properties of spray-dried agglomerated particles of salicylic acid and sodium salicylate
Authors: KAWASHIMA Y , MATSUDA K , TAKENAKA H 
Published: April 2011

Abstract
Aqueous slurries of salicylic acid and sodium salicylate, containing various kinds of binder, namely gum arabic, gelatin, polyvinyl alcohol, carboxymethylcellulose, methylcellulose, polyvinylpyrrolidone, tragacanth and sodium alginate, were spray dried using a centrifugal wheel atomizer. Almost all the spherical dried products were free flowing microgranules, although formulations including gelatin or polyvinyl alcohol proved to be difficult due to agglomeration. Particle properties such as diameter, true density, sphericity and surface area were measured, all of these being strongly influenced by the concentrations of sodium salicylate and binder. The surface topography of the products was studied with a scanning electron microscope. Granules bound with gum arabic and polyvinylpyrrolidone had smooth surfaces without holes or craters. Analysis of the X-ray diffraction patterns and the infrared absorption spectrum of products showed that these granules still contained both salicylic acid and sodium salicylate, in contrast to granules prepared using other binders, where only sodium salicylate remained, the salicylic acid having sublimed. They are microcapsules containing salicylic acid and sodium salicylate of grain size of about 20–80 and 13–17 nm respectively, and amorphous contents of about 50–80%. The thickness of the encapsulating film was 1–3 μm. The change in appearance of a drying slurry droplet is discussed and two typical drying processes are described.
Structure of an iron-dextran complex
Authors: COX J S G , KENNEDY G R , KING J , MARSHALL P R , RUTHERFORD D 
Published: April 2011

Abstract
An iron-dextran complex* from which most of the uncomplexed dextran present had been removed by ultracentrifugation has been examined by electron microscopy and by gel chromatography. In the first technique, freeze-drying to prevent aggregation and distortion followed by shadow-casting with platinum-iridium gave a clear impression of the particulate nature of the complex. The chromatographic experiments on Sephadex G200 confirmed the particle size and showed that the particle size distribution was not wide. The iron-dextran component is thus seen as a small particle of approximately 3 nm diameter when examined only as the FeOOH ‘core’ and of approximately 13 nm diameter when the attached dextran is also observed. A structural model of the particle is presented with the dextran attached by the terminal metasaccharinic acid units to the FeOOH component.
Application of orthogonal functions to spectrophotometric analysis: The Δpj method
Authors: ABDINE H , WAHBI A M , KORANY M A 
Published: April 2011

Abstract
A general method is outlined for the use of orthogonal functions to eliminate interference in differential spectrophotometric analysis. The method is particularly useful when (i) the optimum conditions of the ΔA method are not fulfilled and (ii) the irrelevant absorption is linearly dependent upon the spectrum of the pure compound or its shape is completely unknown. The results obtained for the determination of clemizole in tablets are encouraging and suggest that the method warrants a careful study over a wide field of applications.
The antinociceptive activities of oxotremorine, physostigmine and dyflos
Authors: COX B , THA S J 
Published: April 2011

Abstract
Oxotremorine and physostigmine caused dose-related increases in the hot plate reaction time (HPRT) of mice, but dyflos did not. Physostigmine did not potentiate a low dose of oxotremorine (0.025 mg/kg) in the HPRT test, but some potentiation of higher doses of oxotremorine (0.05 and 0.1 mg/kg) may have occurred. Dyflos did not potentiate any dose of oxotremorine. Physostigmine and dyflos inhibited mouse brain cholinesterase but oxotremorine was without effect. The relation between change of HPRT and cholinesterase inhibition was different for physostigmine and dyflos.
α-Adrenoceptors of aortae from genetically hypertensive rats: reaction with 2-halogenoethylamines
Authors: JANIS R A , TRIGGLE D J 
Published: April 2011

Abstract
The responses of aortic rings from adult spontaneously hypertensive and Carworth normotensive Wistar rats to noradrenaline were compared. The former developed slightly more tension at low, and markedly less tension at high concentrations (&gt; 10−8m) of noradrenaline. The α-adrenoceptors of these tissues were probed using 2-halogenoethylamines to compare quantitatively α-adrenoceptors in normotensive and hypertensive tissue. The kinetics of the recovery of response to noradrenaline from the short-lived antagonism produced by NN-dimethyl-2-bromo-2-phenylethylamine were identical in aortae from both strains of rat. The rate of recovery of response was the same as the rate of loss of tritium from the tissues, suggesting the absence of spare receptors in rat aorta. An estimation of the number of α-adrenoceptors in aortic tissue did not show a difference between normotensive and hypertensive tissues. Evidence is presented that 2-halogenoethylamines react at two kinetically distinguishable sites in rat aorta. The rates of return of response to noradrenaline after receptor blockade with N-(2-bromoethyl)-N-ethyl-N-1-naphthylmethylamine (SY-28) in tissues pretreated with NN-dimethyl-2-bromo-2-phenylethylamine were the same in aortic smooth muscle from both strains of rat. No significant difference was found in the reactions of 2-halogenoethylamine α-adrenoceptor antagonists in aortic tissue from either strain of rat.
The influence of some aliphatic alcohols on the enzymic hydrolysis of methyl hippurate
Authors: DICKINSON N A , REES JUDITH A , COLLETT J H 
Published: April 2011

Abstract
The hydrolysis of methyl hippurate under the influence of α-chymotrypsin and some aliphatic alcohols has been investigated. Methanol, ethanol, n-propanol, n-butanol and n-pentanol were found to inhibit the rate of hydrolysis. The dissociation constants KI for an assumed enzyme-inhibitor complex and KSI for an assumed (enzyme-substrate)-inhibitor complex have been evaluated. In all cases KSI &gt; KI with a ratio of 1·1 to 1 for methanol and 2 to 1 for other alcohols. From the relation between the pK values it is calculated that the free energy change accompanying loss of bound water from each -CH2- group was -2mD1 kJ mol−1.
Effects of narcotic analgesics on contractions of the chick isolated, innervated oesophagus
Authors: BOWMAN W C , BUWEMBO J B 
Published: April 2011

Abstract
The effects of the analgesics, morphine, diacetylmorphine, etorphine, methadone, pethidine, propoxyphene, pentazocine, cyclazocine and phenazocine were studied on contractions of the isolated innervated oesophagus of chicks. All of the analgesics depressed contractions of the oesophagus evoked by coaxial stimulation, the effect being greater the lower the frequency of stimulation. Tachyphylaxis and cross tachyphylaxis to and between the drugs developed rapidly. During the depressant effect on the electrically evoked contractions, responses to acetylcholine and 5-hydroxytryptamine were not depressed, except in the cases of pethidine, propoxyphene and pentazocine which depressed responses to acetylcholine. Nalorphine added during the depressant action antagonized the effects of morphine, diacetylmorphine, etorphine, methadone and phenazocine, partially antagonized those of pethidine and propoxyphene but did not antagonize those of pentazocine or cyclazocine.
Gas-liquid chromatographic estimation of tolbutamide and chlorpropamide in plasma
Authors: PRESCOTT L F , REDMAN D R 
Published: April 2011

Abstract
An improved method for the gas-liquid chromatographic estimation of tolbutamide and chlorpropamide in plasma is described. The drugs are extracted into toluene, back-extracted into alkali and methylated with dimethylsulphate. The methylated derivatives are extracted into n-hexane, concentrated by evaporation and chromatographed on 3·8% UC W98 or 1% Carbowax 20M columns. The standard deviation of replicate analyses of plasma samples containing 20–100 μg/ml of either drug was about 4%. There is no interference from known metabolites of tolbutamide or chlorpropamide.
Measurement of dissolution rates of potassium chloride from various slow release potassium chloride tablets using a specific ion electrode
Authors: Thomas W H 
Published: April 2011

Abstract
The in vitro rates of release of potassium ions from slow-release potassium chloride tablets from 12 sources have been compared. Dissolution rates were determined using a modified non-sink method and a modified sink method. Medicament release in both methods was continuously monitored using a potassium ion specific electrode. The release rate constants were derived and the applicability of the Noyes-Whitney equation, Hixson and Crowell's cube root law and Higuchi's equation was studied.
The adrenoceptors mediating catecholamine effects in frog isolated skin
Authors: Ambalavanar Sivakamy , Foster R W , Schnieden H 
Published: April 2011

Abstract
The short circuit current (s.c.c), potential difference (p.d.) and resistance of the frog skin have been studied. Sympathomimetics increased the s.c.c. in order of relative potency: isoprenaline &gt; salbutamol &gt; noradrenaline. The sympathomimetic-induced increase in s.c.c. was antagonized by propranolol and not by phentolamine. A large concentration of practolol was needed to antagonize the isoprenaline-induced increase in s.c.c. The antidiuretic hormone (ADH)-induced increase in s.c.c. was unaffected by propranolol, practolol or phentolamine. The results suggest that the sympathomimetic-induced increase in s.c.c. is mediated by β2-adrenoceptors.