Biomedical subjects

C Yomota

Publications and source records attributed to C Yomota.

32 records · Page 2Linked to original sources

PubMed1992

[Quality tests for ibuprofen preparations].

Ibuprofen preparations were tested with a view to checking their quality by physical methods such as determination, disintegration and dissolution tests. These studies were carried out on 48 kinds of commercial ibuprofen preparations. The drug content of each preparation was measured by spectrophotometry (264nm), and the values were in the range of 90-110%. In the disintegration tests of 36 tablets, a few tablets of two preparations failed to disintegrate completely after 60 minutes. However the number of such tablets was within the limit specified in JP. The dissolution test described in the USP monograph was also applied to the 36 tablets, and it was found that 9 tablets failed the test provision that over 70% of the tablets must be dissolved within 30 minutes.

Ibuprofen↗

PubMed1991

In-vitro dissolution properties of indomethacin extended-release capsules.

In-vitro dissolution properties of indomethacin extended-release capsules, from samples available on the Japanese market, have been investigated using a continuous flow, column-type dissolution apparatus and the results compared with those obtained by the paddle and the rotating basket methods. A plot of the percent of drug dissolved against the square root of time gave a straight line with the flow-through method but not with the paddle or the rotating basket methods. The results suggest an advantage of the flow-through method over the other two methods when extended-release products are tested by in-vitro dissolution.

Chemistry, Pharmaceutical↗

PubMed1990

[Studies on the degradation of chitosan films by lysozyme and release of loaded chemicals].

Chitosan films with or without chemicals of interest were prepared and degradation properties of chitosan films of themselves by lysozyme and releases of the loaded chemicals from the films were investigated. Enzymatic degradation rate of the films was dependent on the degree of deacetylation of chitosan used and decreased with an increase in its deacetylation. The acidic conditions accelerated the degradation compared to the neutral pH. Most of the water-soluble chemicals used in the present experiments except Coomassie Brilliant Blue with a strong acidic group and pullulan with a high molecular weight (5.8 x 10(4)-38.0 x 10(4], were rapidly released from the films within 1 h. The two chemicals described above were released only in the presence of lysozyme, and their release rates were controlled by the degradation rate of the films.

Biotransformation↗

PubMed1990

[Usage of chitosan as a pharmaceutical material effectiveness as an additional additives of sodium alginate].

Application of chitosan, a deacetylated compound of chitin obtained from shells of shrimps, was investigated with reference to the pharmaceutical excipient for directly compressed tablets. Several drugs were chosen as model compounds and their in vitro dissolution tests were carried out according to the JP XI dissolution test. When chitosan was used alone as an excipient, immediate-release tablets were obtained, as already reported. But when more than 5% of sodium alginate, 1000 cps, was added as excipient, tablets showed an extended-release property under the present experimental conditions.

Adjuvants, Pharmaceutic↗

PubMed1989

Comparison of R- and S-form lipopolysaccharides fractionated from Escherichia coli UKT-B lipopolysaccharide in pyrogen and Limulus tests.

Different LPS was shown to have a relatively different proportion of O-specific chain-less (R-form) LPS by polyacrylamide gel electrophoresis (PAGE) with sodium deoxycholate (DOC). By using DOC-PAGE, S-form LPS having O-chain with approximately 11 repeating units on average (S-Fr) and O-chain-less LPS (R-Fr) were separated from Escherichia coli UKT-B S-form LPS. Significantly stronger pyrogenicity was observed in R-Fr than in S-Fr when measured on the weight basis. Similar result was observed in Limulus test. Comparing biological activities of different S-form LPS, attention should be given to the amounts of co-existing R-form LPS.

Deoxycholic Acid↗

PubMed1989

[Urokinase Reference Standard of National Institute of Hygienic Sciences (Control 881)].

The National Institute of Hygienic Sciences Standard for Urokinase (Control 881) was established in collaboration with five laboratories. This standard contains 1100 international units of urokinase and 1.17 mg of human serum albumin in each ampoule. Urokinase used for the standard is constituted of 1 part of high molecular weight species (M. W. 54000) and 4 parts of low molecular weight species (M. W. 33000).

Drug Stability↗

PubMed1989

[Lysozyme Reference Standard (Control 871) of the National Institute of Hygienic Sciences].

A candidate for the Lysozyme Reference Standard (Control 871) of the National Institute of Hygienic Sciences was prepared. Purity of the standard material examined electrophoretically was more than 99.5%. Lysozyme potency of the standard material was assayed turbidimetrically using dry-cells of Micrococcus luteus as a substrate and compared with that of the Lysozyme Reference Standard (Control 865). Potency of the standard material was in satisfactory agreement with that of the standard and was defined as 1 mg [potency] per mg.

Amino Acids↗

PubMed1989

[Collaborative study of Japanese Pharmacopoeia Heparin Sodium Reference Standard (Control 871)].

Heparin Sodium Reference Standard for Japanese Pharmacopoeia (JP) is replaced with new material derived from porcine mucosa. The material was dissolved in water, distributed to vials and freeze-dried. The anticoagulant activity of the freeze-dried product was determined in collaboration with four laboratories employing JP method. The weighted mean potency of 101 assays was 1515 international units per vial, and this value was adopted for the potency of new JP Heparin Sodium Reference Standard (Control 871). By the antiheparin test of protamine sulfate, 0.712 mg of the new standard was neutralized by 1 mg of protamine sulfate. Molecular weight distribution of this standard was also measured by means of gel permeation chromatography and compared with those of the former reference standard and bovine heparin.

Anticoagulants↗

PubMed1988