PubMed Health⌕ Search

Biomedical subjects

T Arita

Publications and source records attributed to T Arita.

At least 91 records · Page 5Linked to original sources
PubMed1986

Sustained release of nifedipine from granules.

Two kinds of granules were prepared: one with pH-dependent release and the other with pH-independent release. The former was composed of nifedipine, hydroxypropyl methylcellulose phthalate, ethylcellulose, and microcrystalline cellulose, while the latter was composed of nifedipine, hydroxypropyl methylcellulose, ethylcellulose, and corn starch. The effects of the mixing ratios of the polymers and the drug contents in the granules were examined in vitro. In both granules, the release was decreased with the increment of ethylcellulose. These sustained-release granules and the commercial fine granules were orally administered to rabbits. In the plasma levels of nifedipine detected from rabbits orally administered sustained-release granules, a reduced but sustained level was observed. This indicates the sustained release of the drug from the granules in vivo. Furthermore, the plasma profiles of nifedipine indicated that the granules with pH-independent release were superior to that with pH-dependent release with respect to prolonging the effective plasma levels and to minimizing the intersubject variations.

Animals↗
PubMed1986

Interaction of tertiary amines and quaternary ammonium compounds with gastrointestinal mucin.

The binding property of some tertiary amines (chlorpromazine, promethazine and imipramine) and quaternary ammonium compounds (propantheline, mepenzolate and butylscopolamine) for gastric mucin was investigated. All tertiary amines tested bound gastric mucin to varying extents, and the binding of chlorpromazine was especially strong. Moreover, the absorption behaviors of chlorpromazine in rat intestinal loops was significantly inhibited in the presence of gastric mucin. On the contrary, all quaternary ammonium compounds tested did not bind gastric mucin and the absorption of propantheline was not affected in the presence of gastric mucin. These results suggested that gastrointestinal mucin produced a significant effect on the bioavailability of these tertiary amines after oral administration.

Amines↗
PubMed1986

In vitro system of corneal endothelium.

A method for preparation of highly ordered monolayer cultures of the corneal endothelium was described. The technique of agar and palladium double-coating of culture plates was utilized for demarcation of the haptotactic area. The culture plate was prepared by precoating with agar and subsequent coating with palladium to define areas where growth of corneal endothelial cells was allowed. A micro-mass culture of corneal endothelial cells on the area defined by the palladium coating demonstrated their active growth and their reconstitution of the typical cellular pattern of the corneal endothelium.

Animals↗
PubMed1985

Effect of clavulanic acid on inactivated amoxicillin excretion in urinary tract infection.

Oral amoxicillin was taken with and without clavulanic acid by normal subjects and by patients with chronic complicated urinary tract infection to examine the in vitro protective effect of clavulanic acid on amoxicillin degradation. When amoxicillin alone was taken, urinary excretion of the penicilloic acid of amoxicillin in bacteria-positive patients was higher than that in bacteria-negative patients and in normal subjects. There was no comparable change in urinary penicilloic acid excretion in the presence of clavulanic acid. There were significant in vitro protective effects of clavulanic acid on beta-lactamases in the urine.

Administration, Oral↗
PubMed1985

Uptake of amino beta-lactam antibiotics into rat intestinal brush border membrane vesicles.

Uptake of amino beta-lactam antibiotics into rat intestinal brush border membrane vesicles has been examined for characterization of the transport of the antibiotics through the gut wall of the rat. The uptake of cephradine, cephalexin and ampicillin into membrane vesicles was similar, and there were no significant changes in the uptake in the presence of a NaCl or a KCl gradient. These results suggested that the carrier-mediated transport systems relating to amino acids and glucose were not concerned with the intestinal absorption mechanism of amino beta-lactam antibiotics.

Ampicillin↗
PubMed1984

Intestinal absorption of several beta-lactam antibiotics. V. Effect of amino beta-lactam analogues and dipeptides on the absorption of amino beta-lactam antibiotics.

The absorption mechanism of amino beta-lactam antibiotics was investigated by using the whole small intestine of a rat. Mutual inhibition among amino beta-lactam analogues and the effects of dipeptides were studied. The influences of glycylglycine on the absorption of cephradine at the four different parts of intestine were also studied. Similarly to the case of cephalexin and cephradine, the absorption of amoxicillin was significantly inhibited by cyclacillin, cephradine, and cephalexin, but the absorption of ampicillin was not reduced by all tested antibiotics. In the experiments using dipeptides (6.0 mM), the absorption of cyclacillin was reduced significantly by glycylglycine, not by L-carnosine. And cephalexin absorption was influenced by L-carnosine (6.0, 10 mM), not by glycylglycine (6 mM). On the contrary, the absorption of cephradine was not reduced at all by these dipeptides. And from the experiment using the four different parts of intestine, it was shown that the transport interaction of glycylglycine with cephradine was observed in only one segment (the upper part of jejunum). These result suggest that the carrier-mediated transport system correlated to dipeptides participates only to a small degree in the common absorption mechanisms of these amino beta-lactam antibiotics.

Amoxicillin↗