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Biomedical subjects

Y Machida

Publications and source records attributed to Y Machida.

At least 127 records · Page 7Linked to original sources
PubMed1987

Double-layered stick-type formulation of bleomycin for treatment of uterine cervical cancer.

The possibility of continuous release over one week of drugs applied topically was investigated using new stick-type formulations of Brilliant Blue (BB) or bleomycin hydrochloride (BLM). Double-layered sticks of BB or BLM able to adhere to mucosa were prepared by direct compression of the drug, hydroxypropylcellulose-H (HPC) and a carboxyvinyl polymer (Carbopol 934). Drug release in vitro from the sticks was delayed by increasing the weight of the outer layer or the amount of HPC in the outer layer. The sustained release achieved with a double-layered stick having a core coated with an acrylate copolymer (MPM) suggests the possibility of once-a-week treatment of uterine cervical cancer.

Benzenesulfonates↗
PubMed1987

Enhanced percutaneous absorption of ionizable water-soluble drugs.

The percutaneous absorption of diltiazem hydrochloride (DIL) and disodium cromoglycate (DSCG) [representative, respectively, of cationic and anionic water-soluble drugs] was studied in rabbits, using films prepared from water-soluble components. When corresponding fat-soluble counter-ions were added to films prepared using the electrically neutral components polyvinylalcohol and glycerol, the percutaneous absorption of the drugs was enhanced. Furthermore, when non-electrolytes such as BL-9EX or urea were added to the films together with the counter-ions, the bioavailability of the drugs increased. Consequently, it is postulated that ionizable water-soluble drugs are absorbed through skin by forming fat-soluble ion-pairs and additionally that the barrier function against absorption is reduced by non-electrolytes such as BL-9EX or urea. Such non-electrolytes must not hinder the formation of ion-pairs between the drugs and corresponding counter-ions.

Animals↗
PubMed1987

Preparation of polylactic acid-polylipoic acid nanospheres as drug targeting carriers.

Polylactic acid-polylipoic acid nanospheres (PLA-PLIA-NS) were prepared, and their properties as drug targeting dosage forms were evaluated. A computer optimization technique was applied to obtain particles with nanometer order diameters and spherical shapes. Optimum preparative conditions involved the use of 2.4% hydroxypropyl cellulose (HPC), as a stabilizing agent, 24 min ultrasonication time, and 20% PLIA content. PLIA, containing a thiol group, was used for the conjugation of antibodies with the PLA-PLIA-NS surface. In this way, fairly spherical particles of PLA-PLIA-NS with a mean diameter of about 500 nm were obtained. The conjugation was investigated to determine targeting ability more precisely. Using rabbit antihuman IgG (Fab' fragment) antibodies, conjugation with PLA-PLIA-NS was accomplished by a disulphide binding reaction. The PLA-PLIA-NS-antibody conjugates were found to recognize IgG antigen bound to the surface of Sepharose beads.

Drug Carriers↗
PubMed1987

Use of soybean protein for controlled release of drugs administered orally.

The influence of soybean protein (SBP) on the release of drugs from per-oral formulations was investigated, using dl-propranolol as model drug. Directly compressed tablets of SBP/lactose containing more than 40% of SBP did not disintegrate and kept their shape for long periods. Then, dissolution tests (JPX) were carried out with similar tablets containing dl-propranolol hydrochloride as active ingredient. The dissolution profiles showed sustained release of the drug, the dissolution rate being prolonged with increasing amounts of added SBP. Dissolution was affected by the pH of the test medium and accelerated by addition of pancreatin to the test medium. Our results suggest that interaction between SBP, drug and lactose may influence the dissolution rate. Dissolution was unaffected by varying compressional pressure (100-300 kg/cm2) in the preparation of tablets.

Administration, Oral↗
PubMed1987

Per-oral controlled release dosage form of theophylline using soybean protein.

The potential of powdered soybean protein (SBP) as a vehicle for controlled drug release was investigated, using theophylline as the model drug, an in vitro dissolution test and in vivo absorption studies in beagle dogs. The results of the dissolution test demonstrated that the addition of SBP to the tablet brought about retarded dissolution of theophylline. In the in vivo absorption study, Tmax values for theophylline-SBP tablets were larger than those for tablets containing only theophylline; there was no difference in AUC between the two tablets. In addition, there was no detectable difference in the results with theophylline-SBP and Theodur tablets. The practical usefulness of SBP as a vehicle for controlled release tablets was confirmed not only from our in vitro experiment, but also from our in vivo absorption test using beagle dogs.

Administration, Oral↗
PubMed1987

Gel ointment of verapamil for percutaneous absorption.

A gel ointment of verapamil designed for systemic action by transdermal absorption was prepared. The amount of drug released in vitro decreased progressively when increasing amounts (from 20 to 50%) of ethanol-propylene glycol (2:1, v/v) were incorporated into the ointment. Transdermal absorption of the drug in vivo was studied in rats. Verapamil was found in the systemic circulation, and plasma drug levels were maintained at a plateau for 12 hours after application. The effect of two additives on absorption was also examined. Azone, a cycloheptanone derivative, increased plasma levels of verapamil up to tenfold, the effect being greatly dependent on the amount of alcohols in the formulation. Isopropyl myristate did not influence systemic absorption, but it effectively increased absorption into skin. We conclude that the gel ointment can be used for transdermal drug delivery when an adequate absorption promoter is added.

Administration, Cutaneous↗