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At least 37 records · Page 2Linked to original sources
PubMed1982

The pharmaceutical and biological availability of commercial preparations of furosemide.

The pharmaceutical and biological availability of 8 commercial furosemide preparations (6 tablets and 2 preparations with modified release of active ingredient) have been investigated. Two of the tablet preparations showed different rates of drug release in vitro. Additionally they were found to differ significantly in their bioavailability with respect to the maximal plasma concentrations attained after oral administration to healthy volunteers. Bioavailability of the preparations with modified release properties--an enteric-coated tablet and a sustained release preparation in the form of a capsule containing diffusion pellets--was calculated to 80% of that of the rapid releasing tablet used as a standard. Correlations were obtained between the rate of dissolution measured with different techniques and the area under the plasma concentration time curve.

Adult↗
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↗
PubMed2002

Sustained release and biological availability of dalarelin from the biodegradable coacervate microcapsules.

A complex coacervation method was used to prepare microcapsules containing 74.8 +/- 1.5% of the 125I labelled dalarelin incorporated in the gelatine-algin coating. Microcapsules (62 +/- 1.7%) formed, did not exceed a size of 108 microm. The high content of the small size allowed this formulation to be administered by intramuscular injection to rats. It was found that the 125I labelled dalarelin in the form of microcapsules had better bioavailability and was active longer in the rat when compared with the 125I labelled dalarelin solution injections. Dalarelin administered in the microcapsular form was characterised by a higher biological availability. The degree of relative biological availability was calculated as 123% for the dalarelin in the microcapsular form.

Alginates↗
PubMed1996

Measurement of biologically available organic material in intertidal sediments subject to inputs of sea coal or colliery wastes.

A method for the measurement of biologically available organic matter in intertidal or subtidal marine sediments subject to an input of sea coal or colliery wastes is described. The method involves boiling sediment in hydrogen peroxide (H2O2) for 4 h at 160 degrees C to dissolve non-colliery waste organic matter which is then recorded as weight lost after rinsing and drying. Samples are then ashed at 495 degrees C to determine the weight of coal or colliery wastes present. Although H2O2 shows a slight reaction with colliery wastes (overall mean of 0.86% weight loss), it is appropriate to use this technique for the determination of organic matter available to sediment-dwelling biota. We show that shore organic content should not be determined merely by ashing sediment, even on shores which do not appear to contain wastes, since even visibly 'clean' shores in north-east England generally contain some coal fragments in their sediment. Our method is suitable anywhere where biologically available organic matter needs to be measured independently of waste content, e.g. in terrestrial systems close to centres of mining activity.

Journal Article↗
PubMed1984

Biological availability of manganese sources and effects of high dietary manganese on tissue mineral composition of broiler-type chicks.

An experiment was conducted with male broiler-type chicks to study tissue uptake of Mn as a measure of biological availability of Mn sources. A basal corn-soybean meal diet (116 ppm Mn) was supplemented with 0, 1000, 2000, or 4000 ppm Mn as either reagent grade sulfate, carbonate, or monoxide and fed ad libitum for 26 days. No toxic effects were noted as expressed by feed intake, weight gain, feed conversion, hematocrit, hemoglobin, or mortality. Analysis of Mn in tissues revealed a highly linear relationship between liver or bone Mn concentration and dietary Mn for all three sources. Manganese concentration in all tissues increased (P less than .01) as dietary Mn increased. Liver and bone Mn accumulation appeared to be excellent indicators of relative biological availability. On the basis of tissue uptake and solubility tests, MnSO4 X H2O was the most available, followed by MnO and MnCO3, respectively. There were no effects of Mn source or level on concentration of Ca, P, Mg, Cu, Zn, or Fe in tissues studied.

Animals↗
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↗
PubMed1979

[Biological availability of spironolactone in two different galenic forms (author's transl)].

The biological availability of spironolactone in two different galenic preparations (Spiro-Tablinen and Aldactone-100 Caps) was investigated in a single-blind, randomised, cross-over study in six healthy probands. The serum concentration of canrenone after oral intake of spironolactone (100 mg) was investigated in the steady state as well as the renal excretion of canrenone. There were no statistically significant differences between the two preparations either in the course of the serum concentration of canrenone or in the cumulative renal excretion.

Adult↗
PubMed2002

Biological availability of traffic-related platinum-group elements (palladium, platinum, and rhodium) and other metals to the zebra mussel (Dreissena polymorpha) in water containing road dust.

The uptake and bioaccumulation of 15 road dust metals by the zebra mussel (Dreissena polymorpha) were investigated in laboratory exposure studies with emphasis on the traffic-related platinum-group elements (PGEs) palladium (Pd), platinum (Pt), and rhodium (Rh). The biological availability of the metals may depend on water characteristics, so the mussels were maintained in two types of water: nonchlorinated tap water and humic water of a bog lake, both of which contained dust of a moderately frequented road. After an exposure period of 26 weeks, soft tissues of the mussels were freeze-dried and analyzed for the metals. The metal concentrations in the mussel soft tissue ranged from several hundred micrograms per gram (e.g., for iron [Fe]) to less than 10 ng/g (for PGEs). Metal uptake from the road dust by the mussels was found for the PGEs and silver (Ag), bismuth (Bi), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), Fe, lead (Pb), and antimony (Sb). After maintenance of mussels in road dust-contaminated tap water, bioaccumulation factors (BAF = (C(exposed mussels) - C(control mussels))/C(total metal, water), where c is concentration) decreased in the following order: Cu > Cd > Ag > Pd > Sb > Pb > Fe > Pt > Rh. The biological availability of most metals was enhanced by humic water as compared to tap water. Our results show a hitherto unrecognized high availability of Pd for the mussels. Thus, this metal should be monitored more intensively in the environment to assess its distribution in the biosphere.

Animals↗
PubMed1984

Effects of source and particle size on the biological availability of calcium in calcium supplements for growing pigs.

Five experiments were conducted to determine the biological availability of the Ca in high-Ca (calcitic) limestone, dolomitic limestone, oyster shell flour, gypsum, marble dust and aragonite for the growing pig, and to determine the influence of particle size of the Ca source on the bioavailability of Ca. A low-Ca, fortified, corn soybean meal basal diet calculated to contain .2% Ca and .6% P was used. This diet was supplemented with 0 or .3% Ca from either CaCO3 precipitate (the standard) or the test source of Ca. Diets were fed on an ad libitum basis to three to eight replicate pens of pigs (one or two/pen) for 35 to 42 d. Average initial weight of the pigs was 15 kg. At the end of each experiment the pigs were killed, the third and fourth metacarpals and metatarsals and the femurs were removed, and breaking strength and ash were determined. The increase in bone strength from feeding the test source of Ca relative to the increase in bone strength from feeding the CaCO3 standard was used to calculate the relative availability of Ca in the supplements. The bioavailability of Ca in calcitic limestone (two sources), oyster shell flour, gypsum, marble dust and aragonite was similar, ranging from 93 to 102%. However, the Ca in two sources of dolomitic limestone was less available (51 and 78%) than in the other sources. Particle size of the Ca sources (geometric mean diameter of .10 to .54 mm) did not influence the availability of Ca.

Animals↗
PubMed1994

Biological availability and nuclease resistance extend the in vitro activity of a phosphorothioate-3'hydroxypropylamine oligonucleotide.

Augmented biological activity in vitro has been demonstrated in oligonucleotides (oligos) modified to provide nuclease resistance, to enhance cellular uptake or to increase target affinity. How chemical modification affects the duration of effect of an oligo with potent activity has not been investigated directly. We postulated that modification with internucleotide phosphorothioates and 3' alkylamine provided additional nuclease protection which could significantly extend the biological activity of a 26 mer, (T2). We showed this analog, sT2a, could maximally inhibit interferon gamma-induced HLA-DR mRNA synthesis and surface expression in both HeLa and retinal pigmented epithelial cells and could continue to be effective, in the absence of oligo, 15 days following initial oligo treatment; an effect not observed with its 3'amine counterpart, T2a. In vitro stability studies confirmed that sT2a conferred the greatest stability to nucleases and that cellular accumulation of 32P-sT2a in both cell types was also greater than other T2 oligos. Using confocal microscopy, we revealed that the intracellular distribution of sT2a favored greater nuclear accumulation and release of oligo from cytoplasmic vesicles; a pattern not observed with T2a. These results suggest that phosphorothioate-3'amine modification could increase the duration of effect of T2 oligo by altering nuclease resistance as well as intracellular accumulation and distribution; factors known to affect biological availability.

Base Sequence↗
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↗
PubMed2001

Chemical and biological availability of sediment-sorbed benzo[a]pyrene and hexachlorobiphenyl.

This study examined the chemical and biological availability of two nonpolar organic compounds, benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP), from a spiked sediment that was aged for varying amounts of time. Chemical availability was evaluated using four different solvent combinations to extract chemicals from the sediment. The extractability of BaP and HCBP from sediment using traditional solvents was then compared to the transfer efficiency (TE) of a benthic invertebrate (Lumbriculus variegatus) to relate chemical extractability to bioavailability in the organisms. Results indicated that water was the solvent that best approximated bioavailability for BaP, whereas comparisons for HCBP were inappropriate, because TE values exceeded 100%. The inability to obtain a reasonable TE estimate for HCBP was most likely due to the fact that the oligochaetes received a major portion of their uptake from interstitial water instead of ingestion of sediment particles, which invalidated an important assumption of the TE model. Overall, the results of this study indicate that exhaustive chemical extractions may be an inaccurate representation of the bioavailable fractions for some contaminants.

Animals↗
PubMed1978

[Biologic availability and metabolic transit of amino acids modified by technological processing].

The biological availability of amino acids modified by industrial processes has been measured in trials on rats, and their metabolic transit (urinary and faecal excretions, transformation into CO2 and retention in organs) has been studied using molecules labelled with 14C. Maillard reaction products. epsilon-fructose-lysine is not utilized as lysine source. However, less than 10 p. 100 of this substance, bound to proteins, is excreted unmodified in the urine. Intestinal flora destroys most of the fraction which is not absorbed. Premelanoidins are partially absorbed and "burnt" in the organism, whereas high molecularightwe melanoïdins are totally excreted in the faeces. epsilon-(gamma-glutamyl)-lysine and epsilon-(beta-aspartyl)-lysine isopeptides. 80 to 100 p. 100 of free epsilon-(gamma-glutamyl)-lysine are utilized by the Rat. It seems to be absorbed by the intestine, and subsequently hydrolyzed by the kidney, thus releasing lysine. Utilization of this isopeptide bound to proteins has not been shown till now. Free epsilon-(beta-aspartyl)-lysine is not utilized as lysine source. Methionine sulfoxyde and methionine sulfone. Methionine sulfone is not utilized as methionine source whereas most of the free and bound methionine sulfoxide is, in part, it is "reduced" by the liver (perfused liver). Lysino-alanine. Formation of lysino-alanine reduces the availability of lysine and cystine. It is partially excreted in urines, mainly as free lysino-alanine, but also as acetylated derivatives and unknown catabolites.

Amino Acids↗
PubMed2001

Botulinum A toxin: Dysport improvement of biological availability.

We investigated the efficacy and potency of Dysport, a botulinum neurotoxin type A complex approved for therapy, under various conditions. Conditions for maximal expression of biological activity were explored in vitro in the phrenic nerve-hemidiaphragm preparation, while conditions for optimal distribution of the toxin were tested in vivo in a double blind trial involving volunteers, using the foot Muscles extensor digitorum brevis. In contrast to the recommendations of the manufacturer, the biological availability of Dysport could be enhanced by (1) lowering its concentration, (2) supplementing with albumin, and (3) increasing the injection volume. On the basis of these experimental findings Dysport was diluted to a final concentration of 50 U/ml for therapeutic purposes. In a blind, single crossover study patients suffering from various forms of dystonia were treated with Dysport, first diluted and dosed as suggested by the manufacturer and then with doses cut by approximately 70% in accordance with the experimental findings. The low-dose treatment was as effective as the treatment with the recommended higher doses, but side effects were considerably less apparent. The benefits to be derived from these adjustments include a low risk of antibody formation, which could preclude continued or future treatment and substantial cost savings.

Action Potentials↗
PubMed1976

Relationship between the biological availability and solubility rate of reduced iron.

Solubility rate determinations were conducted on electrolytic iron and hydrogen reduced iron and carbonyl iron samples to study the correlation of biological availability and solubility. There was excellent correlation for the hydrogen reduced iron and electrolytic iron samples,. The carbonyl iron samples showed a direct relationship between solubility and bioavailability, but these data were not numerically equivalent to data from other types.

Biological Availability↗
PubMed1985

Biopharmaceutical investigation of rectal suppositories. Part 2(1): Pharmaceutical and biological availability of phenobarbital and phenobarbital-sodium.

The influence of the suppository base and drug solubility on the release an absorption of phenobarbital and phenobarbital-sodium from model suppositories was investigated. It was established that the pharmaceutical and biological availability of phenobarbital is higher from a hydrophilic base because of its improved solubility. The rate and the degree of release of phenobarbital-sodium are more significant from lipophilic bases. The bioavailability of two drug forms-phenobarbital and phenobarbital-sodium--is almost equal after rectal and oral administration.

Animals↗
PubMed1990

[Biological availability of ibuprofen in Imbun 500 suppositories].

Concentration of ibuprofen in rabbit blood was found to be considerably higher after application of Imbun-500 suppositories, containing 500 mg of ibuprofen lysine salt equivalent to 292.6 mg of free ibuprofen, than after application of ibuprofen dragees containing 400 mg of the free drug. Parameters characterizing biological availability of ibuprofen in Imbun-500 suppositories (AUC, Cmax, tmax) were determined. Ibuprofen lysine salt proved to be considerably more easily absorbed from suppositories than ibuprofen from dragees of either home or foreign production.

Absorption↗