SEARCH · PubMed Health

Results for “availability”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,351 records · Page 75Linked to original sources

PubMedDate not supplied

Effect of various vehicles on diclofenac sodium and indomethacin pharmaceutical availability.

The aim of the study was to determine the pharmaceutical availability of various ointment systems containing antirheumatic substances and to establish an optimal system for cutaneous application. Topical application permits elimination or at least reduction of side effects connected with oral administration. Three systems were evaluated: emulsion W/O (ointment), emulsion O/W (cream) and gel, all of them containing diclofenac sodium or indomethacin. The investigated systems are characterized by proper rheological parameters and long physicochemical stability. Studies on diclofenac and indomethacin pharmaceutical availability show a good release of the substances from cream and hydrogel bases, but a very poor release from the ointment base.

Biological Availability↗

PubMed2003

Effect of lime stabilisation of enhanced biological phosphorus removal sludges on the phosphorus availability to plants.

This study investigates the phosphorus (P) availability in lime stabilised biological phosphorus removal sludges. Lime-stabilised sludge amendments (LS), non-stabilised sludge amendments (S) and amendments with a chemical fertiliser (TSP) were compared through plant uptake of P and Olsen-extractable P for this purpose. In the first part of the study, pot experiments were performed, where a dewatered biological phosphorus removal sludge was applied to pots at increasing rates of P. A P-deficient, alkaline soil was used in the experiments and Lollium perenne was the testing plant. In the second part (incubation tests), the waste activated sludge from an Enhanced Biological Phosphorus Removal (EBPR) process was mixed with the same soil at a pre-determined P-based rate. The pot experiments showed that, the efficiency of the fertilising materials, based on the minimum P applied to reach the maximum yield, was in the following order: S approximately equal to LS > TSP. However, the P concentration in the plant tissue was in the order of TSP > S >LS for all P application rates. In the incubation tests, the EBPR sludge raised the soil P-level from the low range to the medium range. The P-availability in TSP decreased rapidly with time whereas that in S and LS remained almost constant.

Biological Availability↗

PubMed2004

[Biological availability of zinc lignosulfonate on calcareous soil of north Guoangdong Province].

Zinc lignosulfonate (Zn-LS) is a kind of organic fertilizers made from the by-products of paper industry. With leach and plot treatments, this paper studied the difference of the biological availability between Zn-LS and an inorganic Zn-fertilizer on calcareous soil of north Guangdong Province. The results indicated that the Zn of Zn-LS was less absorbed by calcareous soil. In soil B, when applying 10 mg x kg(-1) Zn, the dissolved amount of Zn-LS was 65.2% higher than that of inorganic Zn-fertilizer, corn grew well, and its biomass was higher. In soil A, when applying 10 mg x kg(-1) Zn of Zn-LS, the biomass of corn increased by 16.3%, and its Zn content was 81.2% higher. Therefore, biological availability of Zn-LS was better than that of inorganic Zn fertilizer.

Biological Availability↗

PubMedDate not supplied

Dental gel viscosity parameters and pharmaceutical availability of non-steroidal anti-inflammatory drugs.

Model prescription for dental anti-inflammatory gels with carboxymethylcellulose sodium salt and non-ionic surfactants have been worked out. Viscosity parameters of 10 variant gel forms were investigated and an attempt on their interpretation was undertaken in relation to pharmaceutical availability of non-steroidal anti-inflammatory drugs (diclofenac, ibuprofen sodium). Viscosity tests demonstrated higher pharmaceutical availability of ibuprofen sodium than of diclofenac sodium particularly from model gels with surfactants of low number of oxyethylene segments in the structure. The above has been confirmed by in vitro studies on the kinetics of therapeutic agent penetration into external compartment.

Algorithms↗

PubMed2006

Effect of rheological parameters on pharmaceutical availability of ketoprofen from hydrogel products made on Carbopol base.

Rheological parameters were tested in market hydrogel products of anti-inflammatory activity. Their prescription was worked out on Carbopol base. The rate of volatile components loss from pharmaceutical preparations was estimated with gravimetric method, while their viscosity parameters (structural viscosity, yield stress, the area of hysteresis loop) were determined with cone-plate digital rheometer. The kinetics of the therapeutic agent (ketoprofen) release through a standard Viscing membrane to external compartment was tested in hydrogels in vitro. The aim of the study was to determine the relationship between rheological parameters dependent on the prescription of the tested hydrogels and pharmaceutical availability of ketoprofen. Pharmaceutical preparations of anti-inflammatory activity made on Carbopol base are non-Newtonian liquids diluted with shear. Due to ethanol content in their prescription, after application on skin, the increase of structural viscosity and the decrease of ketoprofen pharmaceutical availability accompany the process of volatile components loss from the surface layer of the preparation. Ketoprom hydrogel, having propylene glycol in its composition, is characterized by higher values of viscosity, hysteresis pool area and yield stress than Fastum preparation. Insignificant differences between experimentally determined in vitro areas under the curves of ketoprofen release are associated with rheological parameters of the investigated hydrogels, which was anticipated on the basis of Einstein-Smoluchowski's equation. Ketoprofen penetration from the tested pharmaceutical products on Carbopol base to the external compartment is in accordance with kinetics of "0" order and is diffusion-controlled.

Acrylic Resins↗

PubMed2006

Erythropoiesis activity, iron availability and reticulocyte hemoglobinization during treatment with hemodialysis and in subjects with uremia.

In hemodialysis subjects correction of anemia is facilitated by combined supplementation of intravenous iron and recombinant human erythropoietin. Reticulocyte hemoglobin content (RET-He) is considered to be an actual indicator reflecting functional iron availability for erythropoiesis. In the present study, interdependence between biochemical analytes reflecting iron status and hemocytometric parameters indicating the degree of hemoglobinization of reticulocytes and red blood cells, respectively, is established. Participants of the study were reference subjects (n=75), subjects with iron deficiency anemia (n=52), subjects with uremia (n=19) and subjects undergoing hemodialysis treatment (n=43). If compared with the reference subjects the results for RBC counts and MCHC are statistically significantly decreased in case of subjects with hemodialysis and uremia, whereas increased results are established with regard to RDW-sd values. Significantly increased results for absolute reticulocyte counts and immature reticulocyte fractions (IRF) are also observed in case of subjects with hemodialysis and uremia. Slightly increased values for the ZPP/heme ratio in combination with elevated reticulocyte count reflect increased activity of erythropoiesis. At a definite MCV value, decreased levels for the hemoglobin content of reticulocytes (RET-He) and hemoglobin content of red blood cells (RBC-He) are observed in case of subjects treated with hemodialysis and in subjects with uremia if compared with identical MCV values of the group of reference subjects. For the ratio of RET-He and RBC-He obviously decreased results are demonstrated in case of subjects with iron deficiency anemia (1.02 +/- 0.08, mean +/- SD), hemodialysis (1.05 +/- 0.05) and uremia (1.02 +/- 0.10) if compared with the group of reference subjects (1.11 +/- 0.02). From the combined interpretation of the MCV values within the reference range and decreased values for RET-He and RET-He/RBC-He ratios, respectively, a decreased degree of hemoglobinization is concluded in the case of subjects with hemodialysis or uremia. The conclusion implicating the presumption of reduced functional availability of iron for hemoglobin synthesis is supported by the detection of increased results for sTfR concentrations and ZPP/heme ratios.

Adult↗

PubMed1989

The influence of different formula diets and different pharmaceutical formulations on the systemic availability of paracetamol, gallbladder size, and plasma glucose.

The influence of two liquid formula diets on the systemic availability of paracetamol was investigated in 12 healthy normal volunteers using a liquid and a solid paracetamol dosage form. The diets contained the same balanced amounts, but different patterns of nutrients and different amounts of dietary fiber. Plasma glucose and gallbladder response to the standard meal were used as indicators of gastric emptying. Paracetamol plasma concentrations following application of the liquid dosage form also served as a marker for the gastroduodenal transport of liquid gastric contents. For the liquid dosage form, the plasma concentration time curves did not vary with diet composition. However, with the tablets, a differential effect was observed. Following coingestion with the fiber depleted diet, the rate of systemic availability was reduced more than with the liquid preparation. A further delay was obvious, when the tablets were combined with the meal enriched in dietary fiber. Plasma glucose and gallbladder response did not vary with diet composition. Variations of gastric emptying are unlikely to account for the variability of food effects. Consequently our results illustrate that an interaction of certain meal components with a particular drug dosage form determines the rate of intragastric release of the active compound. This could be shown due to a high standardization of nutrition by using liquid formula diets. Because of the variation of drug release, paracetamol cannot be used as a marker of gastric emptying without taking into account the vehicle necessary for drug application. In contrast to previous studies, our data provide evidence that even balanced test meals retard paracetamol absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗

PubMed1986

[Biological availability of glutamine from N-acetyl-L-glutamine in intravenous administration. Studies in the rat].

Glutamine may be important especially in the catabolic patient, due to its universal role in transamination reactions. Because of its instability, until presently, glutamine is not included in amino acid solutions for parenteral nutrition. The availability of glutamine from the stable derivate N-acetyl-L-glutamine is investigated under the condition of a long-term parenteral nutrition by means of growth, N-balance, and amino acid concentrations in plasma, muscle and urine. For this purpose 2 groups of young healthy male rats (n = 6) are maintained entirely by parenteral nutrition for 12 days. Both groups are given 0.8 g N/kg/24 h as an amino acid solution without containing glutamine. Only one of the groups was supplied additionally with 0.4 g N as N-acetyl-L-glutamine. This resulted in a weight gain of 33 +/- 1.5 g and a cumulative N-balance of 1.5 +/- 0.045 g. In the group in which no acetyl-L-glutamine is given, weight gain is 27 +/- 1.8 g (p less than 0.05) and cumulative N-balance amounts only 1.16 +/- 0.034 g (p less than 0.001). In plasma and urine the amino acid concentrations are significantly elevated for the essential one in this group. The results indicate a good availability of glutamine from N-acetyl-L-glutamine when given intravenously to the rat.

Amino Acids↗

PubMedDate not supplied

[Evaluation of the biological availability of 2 carbamazepine preparations].

The biological availability was determined of two carbamazepine preparations: Amizepin POLFA and Tegretol GEIGY in tablets. The study was carried out in 10 patients giving them the drug in doses of 400 mg by the crossover method at an interval of 3 weeks. The statistical analysis of the mean maximal values, mean times of reaching of maximal concentrations, and mean areas under the curve of serum carbamazepine concentration changes for both forms of the drug showed a comparable biological availability of Amizepin and Tegretol. The relative degree of bioavailability of Amizepin amounted to 98% of that of Tegretol. The values of pharmacokinetic parameters of both drugs were compared. The value of distribution volume was greater in the case of Tegretol, and the difference was statistically significant. No significant differences were found between the remaining calculated parameters.

Adult↗

PubMed1985

Comparative bio-availability of four formulations of furosemide.

Twelve healthy white male volunteers participated in a randomized double-blind cross-over study to compare the bio-availability of four brands of furosemide marketed in the RSA. A 40 mg tablet of each of the following formulations, purchased at random, was administered: Aquasin; Furetic; Lasix; and Puresis. Blood specimens were taken up to 5 hours and urine specimens collected up to 6 hours after medication. The following parameters were used to compare the formulations: (i) area under the plasma concentration time curve (AUC); (ii) maximal plasma concentration of furosemide (Cmax); (iii) time to maximal furosemide plasma concentration; (iv) cumulative urine volumes; and (v) cumulative excretion of furosemide in urine. Lasix was significantly superior to the other three products in respect of AUC and Cmax. With regard to cumulative urine volumes Lasix was significantly (P less than 0,05) superior to Aquasin in the first 3 hours after medication, significantly superior (P less than 0,05) to Puresis and comparable to Furetic over the entire 6-hour collection period. Lasix resulted in a significantly greater cumulative urinary excretion of furosemide than Puresis and Aquasin over the entire collection period. Lasix was superior to Furetic at 6 hours after medication. It is concluded that the bio-availability of Lasix is superior to that of the other products tested.

Adolescent↗

PubMed1979

[Comparison of bio-availability, antianaemic efficacy, tolerance and drug costs in oral iron(II) and iron(III) preparations (author's transl)].

In addition to a clinical study which investigated the bio-availability of three oral iron preparations S, L and X by using postabsorption serum iron concentration curves, the same drugs were compared in order to study their antianaemic efficacy, tolerance and drug costs arising during and iron therapy. Moreover, these iron drugs were related to other current clinical reports. Within all three iron preparations a very good correlation was found between bio-availability and haematopoietic efficacy: The very good absorbability of the bivalent quick release stick capsule preparation S (= 100%) corresponded with a very good capacity of haemoglobin regeneration (2,6 +/- 0,4 g Hb/1/day) whereas due to a very low absorbability (10% to 16%) the antianaemic efficacy of both iron(III) preparations L and X had to be rated as moderate to predominantly poor. In normal therapeutic dosis all three iron preparations showed no differences in tolerance. The ratio of side effects was similar to that after ingestion of placebo. In comparing the drug costs during a therapy leading to a real absorption of 1 g of iron the most effective iron(II)sulfate preparation S is 3.6 to 12.6 times cheaper than the compared trivalent preparations L and X. Therefore, there is no justification for the further production or introduction on the market of trivalent iron preparations.

Absorption↗

PubMed1985

[Availability of propylphenazocine from suppositories. 1. In vitro bioavailability].

Comparing examinations of the in-vitro availability of propyphenazone from suppositories of different fat bases (Rosupol U, Witepsol H 15) did not display any differences in the release behaviour. Compared with propyphenazone preparations, aminophenazone suppositories of the same concentration exhibit a significantly increased in-vitro availability.

Antipyrine↗

PubMed1979

[Biological availability of digoxin from a combination drug].

In a randomized cross-over study with 14 voluntary test persons the absolute biological availability of digoxin in Card-Dusodril 1/8 and 1/4 respectively was investigated. 6 test persons received 4 drag. Card-Dusodril 1/8 (= 0.5 mg digoxin), 8 test persons 4 drag. Card-Dusodril 1/4 (= 1 mg digoxin) orally, in comparison to the corresponding group with intravenously applied digoxin as standard. Based on the cumulative digoxin excretion in the urine an absolute biological availability of Card-Dusodril 1/8 of 79%, of Card-Dusodril 1/4 of 76% could be demonstrated. With regard to an average resorption of oral digoxin preparations of approx. 70%, the present values, which correspond in direct comparison to those of acetyl digoxin, can be considered good. Maximum serum levels were achieved after 86 +/- 6.8 minutes which also indicates a quick resorption.

Administration, Oral↗

PubMed1979

Studies on the phytate: zinc molar contents in diets as a determinant of Zn availability to young rats.

1. Studies were carried out in vitro to examine the effects of phytate on the solubility of the trace elements zinc, copper and manganese. Appropriate volumes of a solution of sodium phytate were added to a mineral solution to achieve phytate: Zn values of from 0 : 1 to 45 : 1. In a second series the same values for phytate: Zn were achieved by varying the amount of added Zn at a fixed phytate concentration. 2. In both experiments greater than 85% of the Zn was rendered insoluble at pH 6.5 even at the lowest value for phytate: Zn (5 : 1). The effect of phytate on Zn solubility was greater than effects on Cu or Mn. 3. In a dietary study, rats were offered a semi-synthetic egg-albumin-based diet with added phytate. Two series of diets were prepared, the first had a constant Zn content (18.5 mg Zn/kg) and the amount of sodium phytate varied so as to achieve values for phytate: Zn of from 0 : 1 to 40 : 1 (series 1). In the second series, the same values for phytate: Zn were achieved by adding a fixed amount of phytate (7.4 g phytic acid/kg) while the amount of Zn was varied (series 2). 4. Dietary phytate caused significant reductions in growth rates, plasma Zn concentrations and hair Zn concentrations and greying of the coat at values for phytate: Zn of 15 : 1, 10 : 1, 15 : 1 and 15 : 1, respectively. 5. While phytate was apparently slightly more effective in reducing Zn status when phytate: Zn values were achieved at the lower absolute levels of phytate and zn (series 1 diets), the differences at equivalent phytate: Zn values were small. It was concluded that phytate: Zn values can be used as an indicator of Zn availability from phytate-rich diets. 6. Rats offered three diets containing soya-bean-based textured-vegetable-protein (TVP) exhibited low rates of weight gain compared with rats offered an egg-albumen-based diet of similar Zn content (14.5 mg Zn/kg). Additional Zn supplied in drinking-water (25 mg Zn//l) was without effect on rats consuming the egg-albumin diet but significantly improved the weight gain of rats on the TVP diets. 7. It was concluded that phytate naturally present in TVP behaves similarly to phytate added to an otherwise phytate-free diet and that the reduced availability of Zn in TVP diets can be accounted for entirely by their phytate contents.

Animals↗

PubMed1984

Availability of amino acids in monogastric animals. Variations of digestive origin.

The supply of amino acids to the organism, required for maximum protein synthesis, results from several interdependent digestive processes: the sequential degradation of dietary proteins during their passage in the gastro-intestinal tract, and the absorption of their hydrolysis products. In this paper we survey the possible variations in these phenomena which are liable to affect amino acid availability. Concerns the transit of amino acids, we first examine gastric emptying which determines the length of stay of digestion products in the stomach and their passage to the small intestine. Thereafter the transit of digesta at the ileo-caeco-colic junction where the quantitative, qualitative and kinetic aspects of digestion in the small intestine may be investigated. The influence of the nature of proteins, and of their technological treatments is studied as well as the possible occurrence of a differential transit of free amino acids as compared to that of proteins and of proteins as compared to that of the carbohydrate fraction. With respect to enzyme hydrolysis, two kinds of problems may be considered: the accessibility of proteins to enzymes (due to the structure of proteins or of the other dietary components, or due to antinutritional factors), and the mode of action of some of the proteases (in particular trypsin, in relation with the involvement of technological treatments). The mechanisms thought to operate for normal absorption of free amino acids and oligopeptides are discussed, followed by some data concerning the absorption of amino acid derivatives, appearing during technological processing, and their influence on the absorption of normal forms of amino acids. The fate of the residual nitrogenous fraction in the large intestine, that is after the sites of amino acids release and absorption, is surveyed. A fundamental knowledge of these physiological processes may lead to development of methods estimating the yield of protein utilization in the digestive tract, based on the measurement either of amino acid disappearance from the lumen or of amino acid appearance in the portal blood. Digestion is a key step in the availability of amino acid, but it only gives a partial picture of this process. Therefore, its study should also be related to that of amino acid metabolism and overall protein synthesis.

Amino Acids↗

PubMed1983

[Effect of adjuvants on the pharmaceutical and biological availability of chlorpromazine hydrochloride].

It is reported of the influence of adjuvants upon the pharmaceutical and biological availability of chlorpromazine hydrochloride from tablets. Sodium carboxymethyl cellulose, microcrystalline cellulose (Heweten 40) and potato starch have been used for tabletting. The adjuvants added act on the pharmaceutical availability, certain differences being due to a discriminate swelling behaviour. The differences observed in vitro exert no effect on the bioavailability of the drug in the rabbit. Thus, the tablets produced with the adjuvants mentioned have proved to be preparations of almost equivalent similar biopharmaceutical behaviour.

Animals↗

PubMed1984

The availability of therapeutic hydroxocobalamin to cells.

Hydroxocobalamin (OH-Cbl), when used to treat vitamin B12 deficiency, is better retained by the body than is cyanocobalamin (CN-Cbl), but the availability to cells has not been studied systematically. In a series of experiments, we compared the uptake and internalization of OH-Cbl and CN-Cbl bound to transcobalamin II (TCII) by a human cell model, the HeLa cell. TCII-OH-Cbl was: (1) taken up in larger amounts per unit time, (2) the greater uptake was not a consequence of more effective attachment to receptors of TCII-Cbl nor to a more rapid regeneration of receptors, (3) the difference was expressed during the phase of internalization of TCII-Cbl, (4) with CN-Cbl, the stages of binding to receptors plus internalization were more readily reversed, and (5) larger amounts of OH-Cbl were internalized and converted to active coenzyme forms of Cbl. When injected into a healthy person, 200 micrograms of OH-Cbl was better retained in the circulation than 200 micrograms of CN-Cbl. When added in vitro in equivalent amounts, more OH-Cbl was bound to nonspecific plasma proteins. This greater and broader binding neither enhanced nor interfered with the uptake of Cbl by cells, which was determined by the amount of Cbl bound physiologically to TCII. It was concluded that OH-Cbl is a more efficient form of treatment of the common types of Cbl deficiency, principally because of the better retention, which requires less frequent injections, but also because of greater availability to cells.

Animals↗

PubMed1983

The pharmacokinetics and availability of niflumic acid in humans.

The pharmacokinetic parameters and relative availability of niflumic acid in two different pharmaceutical preparations were studied in 12 subjects after a single oral administration. Total plasma clearance averaged 45 ml/min, and the half-life of elimination approximately 2 h, giving a distribution volume of 0.12 l/kg on the average. The values of these pharmacokinetic parameters were in agreement with the general characteristics of this type of substance, a weak acid strongly bound to plasma proteins. Comparison of the systemic availability of the two oral forms showed no difference; they were probably close to 100%.

Absorption↗