Topic:Absorption
Absorption in horses refers to the process by which drugs and nutrients are taken up from the gastrointestinal tract into the bloodstream. This page compiles peer-reviewed research that examines the mechanisms underlying uptake, bioavailability, and the factors influencing absorption rates in horses. The studies explore pharmacokinetic profiles, the impact of different formulations, and how physiological conditions affect dietary absorption.
Chronic eosinophilic gastroenteritis in the horse. Four cases of chronic eosinophilic gastroenteritis in horses are described. The disease was manifested clinically by weight loss, malabsorption and diarrhea of soft, formless feces. A chronic inflammatory reaction, with diffuse and focal eosinophilic infiltrates, was present in the esophagus, stomach, small and large intestine, and mesenteric lymph nodes. The cause of the lesion was not determined but was thought to the due to an ingested allergen, as the lesion is indicative of an on-going, immediate hypersensitivity reaction. One horse had generalized acanthosis, hyperkeratosis, and ulcerati...
Bioavailability of phenylbutazone preparations in the horse. Plasma phenylbutazone concentrations were determined for up to 12 h in 6 horses following intravenous and oral phenylbutazone administration. To evaluate the bioavailability of different oral preparations, phenylbutazone was administered in a paste as well as the traditional powder form. The effect of the state of stomach contents on the absorption of phenylbutazone was investigated by administering the paste before and after feeding; the powder was given in a small bran mash and a full feed of lucerne chaff, wheaten chaff and bran. Despite great variability among individual horses both the pa...
Factors affecting absorption of non-steroidal anti-inflammatory agents in the horse. The absorption of orally administered phenylbutazone (5 mg/kg) was studied in 10 thoroughbreds, eight ponies and four pony foals. Large variations in area under the curve (AUC) and peak plasma concentrations were found both within an animal and within groups of animals. Administration of phenylbutazone (5 mg/kg) following an overnight fast resulted in no difference among the three groups of animals with respect to AUC (0 to 24 hours), mean (+/- sd) values of which were 132 +/- 68, 107 +/- 48 and 98 +/- 6, respectively. Absorption characteristics of two oral phenylbutazone preparations (Equipal...
Serum concentrations of trimethoprim and sulfadiazine following oral paste administration to the horse. Two fasted and 2 fed horses were dosed orally with a combined trimethoprim and sulfadiazine paste formulation at a dose of 35 mg (1:5 combined active ingredients)/kg. Serum concentrations of each drug were determined periodically for 3 consecutive days for the 4 horses. The extent and rate of absorption for trimethoprim were variable, but peak serum concentrations occurred generally within 3 hours; sulfadiazine absorption was slower, reaching peak concentrations by 6 hours. Fasting did not have a consistent effect on the serum concentration profiles for either drug. Both drugs achieved serum c...
The pharmacokinetics of meclofenamic acid in the horse. The pharmacokinetics of meclofenamic acid were studied in Thoroughbred horses and in ponies. After intravenous (i.v.) administration of either 2 mg/kg or 4 mg/kg sodium meclofenamate the elimination half-life was of the order of 0.9 h while the volume of distribution was found to be 0.128 litre/kg. Elimination was in accordance with a one-compartment model. Following oral administration of either meclofenamic acid (4 mg/kg) or sodium meclofenamate (4 mg/kg) a much longer terminal half-life than that calculated for Kel from i.v. data was found. This anomaly indicated that the 'flip-flop' phenom...
[Methods for the evaluation of the intestinal function in the horse (author’s transl)]. Diagnostic tests in horses showing signs of gastrointestinal diseases are reviewed. The use of rectal exploration is emphasized, and paracentesis as a diagnostic aid is mentioned. Special attention is given to the absorption tests as they are easy to conduct and give a relative measure of the absorptive capability of the intestinal epithelium. Glucose, D(+)-xylose and carbohydrate digestion-absorption tests are compared, and the D(+)-xylose absorption test is preferred because of the univocal curve of absorption (see Figure 1 and 2). The absorption curve in a horse suffering from alimentary ly...
Influence of dietary molybdenum on copper metabolism in ponies. The effects of molybdenum ingestion on copper metabolism were investigated in bile duct-cannulated ponies fed diets containing 1.01, 27.4 and 107.3 ppm molybdenum. Copper metabolism was assessed by examination of 64Cu and stable copper excretion in feces, bile and urine. The addition of molybdenum to the diet decreased copper absorption and retention as a consequence of increased excretion of dietary copper in feces and increased excretion of absorbed copper in bile. Only 5% or less of the absorbed copper was excreted in urine regardless of dietary treatment. Biliary molybdenum excretion was o...
Absorption, excretion and tissue distribution of stable zinc and 65zinc in ponies. Absorption excretion and tissue distribution of stable Zn and 65Zn in mature ponies were studied in three experiments. In the first experiment, the metabolism of stable, dietary Zn and intravenously administered 65Zn was studied in three ponies in a 3 X 3 Latin square design. The ponies were fed a corn and beet pulp diet containing 35 mg Zn/kg or the same diet with 250 or 520 mg of supplemental Zn as ZnO. The ponies absorbed and retained more stable Zn when fed 250 mg of supplemental Zn that when fed the basal diet alone or the basal diet plus 520 mg of supplemental Zn. The ponies retained mor...
Inhibition of calcium absorption in ponies fed diets containing oxalic acid. The effects of dietary oxalic acid on absorption, excretion, and retention of calcium was determined in Shetland ponies in 2 experiments. In each experiment, the results of feeding a control diet consisting of oats, molasses, and a complete pelleted horse ration were compared with those of feeding the control diet plus 1% oxalic acid. The diets contained 0.6% calcium in the 1st experiment and 0.45% calcium in the 2nd experiment. Oxalic acid increased the fecal excretion of calcium and decreased calcium absorption. The endogenous fecal excretion of calcium determined in the 1st experiment, usin...
Absorption of sodium benzylpenicillin from the equine uterus after local Lugol’s lodine treatment, compared with absorption after intramuscular injection. Plasma concentrations of sodium benzylpenicillin following intrauterine infusion were increased by reducing the volume of solution and expelling air from the vagina after infusion. Instillation of 10 per cent Lugol's iodine solution into the uterus before penicillin infusion further increased the absorption rate, although peak plasma levels of penicillin were less than half those which resulted from intramuscular injection of the same dose.
The catalytic metal atoms of cobalt substituted liver alcohol dehydrogenase. The catalytic and non-catalytic Zn atom pairs of horse liver alcohol dehydrogenase (LADH) have been replaced sequentially either by 65Zn, Co or 65Zn and Co. The Co derivatives exhibit characteristic spectra. When Co replaces the Zn atoms which exchange secondly, enzymatic activity is altered, and both imidazole and 1,10-phenanthroline (OP) significantly modify the spectrum of the catalytic Co atoms. Further, due to the removal of cobalt, the instantaneous and reversible OP inhibition of the native enzyme becomes time-dependent and irreversible. Jointly, these data identify the pair of metal at...
Carbohydrate digestion and absorption in the equine small intestine. Dietary carbohydrates, which constitute a most important source of equine nutrition, are digested and absorbed by a series of complex processes principally in the small intestine, beginning with intraluminal starch hydrolysis by the action of pancreatic amylase. The continuous secretion of a copious volume of pancreatic juice, low in enzyme activity, presumably releases sufficient oligosaccharides for further hydrolysis at the intestinal cell surface by brush border enzymes. Active carrier mediated mechanisms then transport the final hexose products across the intestinal cell for uptake in the...
Cobalt metabolism in horse. Serum level and biosynthesis of vitamin B12. The levels of serum vitamin B were determined on 16 mature partly warm-blooded, partly Finnish rural-race horses by the radioisotopic competitive inhibition assay method. The mean value from three samplings carried out in dupli- or triplicate was 1.54 ± 0.16 ng/ml. The utilization of serum inorganic cobalt for cyanocobalamin synthesis was studied on two geldings, which received a dose of 200 µCi CoGl i.v. A Sephadex G-100 gel filtration was carried out with the serum proteins from serial blood samplings at different time intervals 15 min. to 48 hrs. after administration. The gel filtration s...
The D(+) xylose absorption test in the horse. SUMMARY
A D(+) xylose absorption test has been standardised for use in the horse. A dose of 2 g. xylose/Kg. body-weight is required to produce a maximum plasma xylose level of 30 mg./100ml. after two hours. There are limitations to the procedure being used as a routine clinical screening test of small intestinal dysfunction in the horse.
RÉSUMÉ
On a standardisé un test d'absorption du D(+) xylose pour le cheval.
Une dose de 2 gr de xylose par kilo de poids vif est nécessaire pour produire une élevation du xylose plasmatique jusqu'à 30 mg par 100 ml après deux heures.
Il y a d...