Patents by Inventor Masayuki Yokoyama

Masayuki Yokoyama has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5510103
    Abstract: The present invention relates to drug carriers composed of a block copolymer having hydrophilic and hydrophobic segments, a polymeric micelle type drug comprising hydrophobic drugs trapped by physical treatments in said drug carrier and methods for trapping hydrophobic drugs in the drug carrier. The drugs carrier composed of the block copolymer according to the invention forms a stable polymeric micelle structure with which hydrophobic drugs can be incorporated very efficiently via physical trapping. It was found that the incorporated drug is stably maintained in micelles even in the presence of serum. In addition, a drug difficult to administer into the living body owing to sparing water-solubility for its high hydrophobicity can be administered in the form of polymeric micelle drug.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: April 23, 1996
    Assignee: Research Development Corporation of Japan
    Inventors: Masayuki Yokoyama, Yasuhisa Sakurai, Teruo Okano, Kazunori Kataoka
  • Patent number: 5483008
    Abstract: The present invention relates to a bifunctional polyether having groups different from each other at both ends, with a polymerization degree of 5 to 10000 and consisting of repeating units each represented by the following formula (I): ##STR1## (wherein R.sub.1, represents a hydrogen atom, halogen atom, or a lower alkyl group optionally substituted by a halogen atom, and R.sub.1 in each repeating unit may be the same or different), as well as to a process for the preparation thereof and a polymerization initiator therefor. The process of production and polymerization initiator of the present invention enable 100% introduction of a primary amino group into one of the ends of polyether.
    Type: Grant
    Filed: February 5, 1993
    Date of Patent: January 9, 1996
    Assignee: Research Development Corporation of Japan
    Inventors: Yasuhisa Sakurai, Teruo Okano, Masayuki Yokoyama, Kazunori Kataoka, Yukio Nagasaki, Nobuyuki Ohsako, Masao Kato
  • Patent number: 5478575
    Abstract: The present invention provides a polymer complex of a sugar response type having boronic acid groups in the polymer. Medicines may be contained or linked, preferably, the medicines have hydroxy groups. The polymer having boronic acid groups and the medicine having hydroxy groups may be linked by boronic acid ester bonds. The complex may also comprises polymers having boronic acid groups and polymers having hydroxy groups, and these polymers may be cross-linked.
    Type: Grant
    Filed: March 26, 1993
    Date of Patent: December 26, 1995
    Assignee: Nippon Oil & Fats Co., Ltd.
    Inventors: Tsuyoshi Miyazaki, Yoshishige Murata, Daijiro Shiino, Kazunori Waki, Yasuhisa Sakurai, Teruo Okano, Kazunori Kataoka, Yoshiyuki Koyama, Masayuki Yokoyama, Shigeru Kitano
  • Patent number: 5449513
    Abstract: The present invention relates to drug carriers composed of a block copolymer having hydrophilic and hydrophobic segments, a polymeric micelle type drug comprising hydrophobic drugs trapped by physical treatments in said drug carrier and methods for trapping hydrophobic drugs in the drug carrier. The drugs carrier composed of the block copolymer according to the invention forms a stable polymeric micelle structure with which hydrophobic drugs can be incorporated very efficiently via physical trapping. It was found that the incorporated drug is stably maintained in micelles even in the presence of serum. In addition, a drug difficult to administer into the living body owing to sparing water-solubility for its high hydrophobicity can be administered in the form of polymeric micelle drug.
    Type: Grant
    Filed: August 11, 1993
    Date of Patent: September 12, 1995
    Assignee: Research Development Corporation of Japan
    Inventors: Masayuki Yokoyama, Yasuhisa Sakurai, Teruo Okano, Kazunori Kataoka
  • Patent number: 5412072
    Abstract: This invention is a water-soluble high molecular polymerized drug comprising a water-soluble clock copolymer having a hydrophilic segment and a hydrophobic pharmacological-functioning segment to side chain of which a drug is bonded. The hydrophilic first segments of the present invention include polyethylene glycol, polysaccharides, polyacrylamide, and so on. The hydrophobic segments being attached to a drug include polyaspartic acid, polyglutamic acid, polylysine, or derivatives thereof. Drugs to be attached to the hydrophobic segment include anti-cancer drugs, drugs for central nerve, drugs for circulatory organs, and so on.
    Type: Grant
    Filed: March 21, 1990
    Date of Patent: May 2, 1995
    Assignee: Research Development Corp. of Japan
    Inventors: Yasuhisa Sakurai, Teruo Okano, Kazunori Kataoka, Noriko Yamada, Shohei Inoue, Masayuki Yokoyama