Patents by Inventor Zhong Zhao

Zhong Zhao 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).

  • Publication number: 20020091230
    Abstract: Biodegradable terephthalate polymers are described comprising the recurring monomeric units shown in formula I: 1
    Type: Application
    Filed: August 2, 2001
    Publication date: July 11, 2002
    Inventors: Hai-Quan Mao, Kam W. Leong, Wenbin Dang, Hungnan Lo, Zhong Zhao, David P. Nowotnik, James P. English
  • Patent number: 6403675
    Abstract: Biodegradable, flowable or flexible polymer compositions are described comprising a polymer having the recurring monomeric units shown in formula I: wherein: each of R and R′ is independently straight or branched alkylene, either unsubstituted or substituted with one or more non-interfering substituents; L is a divalent cycloaliphatic group; R″ is selected from the group consisting of H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and n is 5 to 1,000, wherein said biodegradable polymer is biocompatible before and upon biodegradation. In one embodiment, one or more of R, R′ or R″ is a biologically active substance. Amorphous compositions containing a biologically active substance, in addition to the polymer, and methods for controllably releasing biologically active substances using the compositions, are also described.
    Type: Grant
    Filed: April 30, 1998
    Date of Patent: June 11, 2002
    Assignees: Guilford Pharmaceuticals, Inc., Johns Hopkins University
    Inventors: Wenbin Dang, Hai-quan Mao, Irina Kadiyala, Kam W. Leong, Zhong Zhao, James P. English
  • Patent number: 6376644
    Abstract: Biodegradable polymers are described comprising the recurring monomeric units shown in formula I or II: wherein X is —O— or —NR′—, where R′ is H or alkyl; L is a branched or straight chain aliphatic group having from 1-20 carbon atoms; M1 and M2 are each independently (1) a branched or straight chain aliphatic group having from 1-20 carbon atoms; or (2) a branched or straight chain, oxy-, carboxy- or amino-aliphatic group having from 1-20 carbon atoms; Y is —O—, —S— or —NR′—, where R′ is H or alkyl; R is H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; the molar ratio of x:y is about 1; the molar ratio n:(x or y) is between about 200:1 and 1:200; and the molar ratio q:r is between about 1:99 and 99:1; wherein said biodegradable polymer is biocompatible before and upon biodegradat.
    Type: Grant
    Filed: September 1, 2000
    Date of Patent: April 23, 2002
    Assignees: Guilford Pharmaceuticals, Inc., Johns Hopkins University School of Medicine
    Inventors: Hai-Quan Mao, Kam W. Leong, Zhong Zhao, James P. English
  • Publication number: 20020028911
    Abstract: The present invention provides improved processes for purifying polymer preparations by removing contaminants, such as metal contaminants. The present invention also provides improved processes for producing phosphopolymers, which can yield improved polymers in terms of molecular weight, homogeneity, consistency and purity. Polymers and polymer preparations also are provided. The present invention is time, labor and energy efficient, and thus marks an improvement over past approaches.
    Type: Application
    Filed: June 21, 2001
    Publication date: March 7, 2002
    Inventors: Deborah Barnette, James English, Keith Branham, Donna Hall, Reuben Land, Doug Mink, Zhong Zhao
  • Patent number: 6322797
    Abstract: Biodegradable terephthalate polymers are described comprising the recurring monomeric units shown in formula I: wherein R is a divalent organic moiety; R′ is an aliphatic, aromatic or heterocyclic residue; x is ≧1; and n is 0-5,000, wherein the biodegradable polymer is biocompatible before and upon biodegradation. Processes for preparing the polymers, compositions containing the polymers and biologically active substances, articles useful for implantation or injection into the body fabricated from the compositions, and methods for controllably releasing biologically active substances using the polymers, are also described.
    Type: Grant
    Filed: April 2, 1998
    Date of Patent: November 27, 2001
    Assignees: Guilford Pharmaceuticals, Inc., Johns Hopkins University
    Inventors: Hai-Quan Mao, Kam W. Leong, Wenbin Dang, Hungnan Lo, Zhong Zhao, David P. Nowotnik, James P. English
  • Patent number: 6166173
    Abstract: Biodegradable polymers are described comprising the recurring monomeric units shown in formula I or II: wherein X is --O-- or --NR'--, where R' is H or alkyl; L is a branched or straight chain aliphatic group having from 1-20 carbon atoms; M.sub.1 and M.sub.2 are each independently (1) a branched or straight chain aliphatic group having from 1-20 carbon atoms; or (2) a branched or straight chain, oxy-, carboxy- or amino-aliphatic group having from 1-20 carbon atoms; Y is --O--, --S-- or --NR'--, where R' is H or alkyl; R is H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; the molar ratio of x:y is about 1; the molar ratio n:(x or y) is between about 200:1 and 1:200; and the molar ratio q:r is between about 1:99 and 99:1; wherein said biodegradable polymer is biocompatible before and upon biodegradat.
    Type: Grant
    Filed: April 2, 1998
    Date of Patent: December 26, 2000
    Assignees: Guilford Pharmaceuticals Inc., Johns Hopkins University
    Inventors: Hai-Quan Mao, Kam W. Leong, Zhong Zhao, James P. English
  • Patent number: 6153212
    Abstract: A medical device is described comprising a biodegradable terephthalate copolymer comprising the recurring monomeric units shown in formula I below: ##STR1## wherein R is a divalent organic moiety; R' is an aliphatic, aromatic, or heterocyclic residue; x is .gtoreq.1; and n is 3-7,500, and where the biodegradable terephthalate copolymer is sufficiently pure to be biocompatible and is capable of forming biocompatible residues upon biodegradation. In addition, compositions containing the copolymers and biologically active substances, articles useful for implantation or injection into the body fabricated from the compositions, and methods for controllably releasing biologically active substances using the copolymers, are also described.
    Type: Grant
    Filed: October 2, 1998
    Date of Patent: November 28, 2000
    Assignees: Guilford Pharmaceuticals Inc., Johns Hopkins University School of Medicine
    Inventors: Hai-quan Mao, Kam W. Leong, Zhong Zhao, Wenbin Dang, James P. English, David P. Nowotnik
  • Patent number: 6028163
    Abstract: A process for making a high molecular weight poly(phosphoester) comprising the recurring monomeric units: ##STR1## wherein X is --O-- or --NR"--, where R" is H or alkyl; L is a divalent organic moiety, with the proviso that L cannot have the formula ##STR2## R' is H, alkyl, alkoxy, aryl, aryloxy, heterocyclic, or heterocycloxy; and n is from about 25 to 2000,is described. The process comprises the steps of:(a) substantially dissolving p moles of a di-XH compound in a solvent comprising more than 75% toluene at a first temperature between about -75.degree. C. and 60.degree. C. to form a reaction mixture;(b) while maintaining the reaction mixture at the first temperature, adding q moles, where p.apprxeq.q, of a phosphorodihalo compound;(c) gradually increasing said first temperature at a rate of less than about 2.degree. C. per minute as necessary to achieve a second temperature between about 0.degree. C. and 110.degree. C.
    Type: Grant
    Filed: June 27, 1997
    Date of Patent: February 22, 2000
    Assignee: Guilford Pharmaceuticals Inc.
    Inventor: Zhong Zhao
  • Patent number: 6008318
    Abstract: A process for making a phosphoester polymer comprising the recurring monomeric units of formula I: ##STR1## wherein: X is --O-- or --NR"--, where R" is H or alkyl;L is a divalent organic moiety;R' is H, alkyl, alkoxy, aryl, aryloxy, heterocyclic, or heterocycloxy; andn is between about 25 to 2,000,is described. The process comprises the steps of:(a) polymerizing in the presence of a solvent p moles of a di-XH compound having formula II:H--X--L--X--H IIwherein X and L are as defined above, with q moles, where p.apprxeq.q, of a phosphorodihalo compound to form a polymer of formula I, wherein n is about 12 to 1000, having a first molecular weight Mw.sub.
    Type: Grant
    Filed: June 17, 1998
    Date of Patent: December 28, 1999
    Assignees: Guilford Pharmaceuticals Inc., Johns Hopkins University
    Inventors: Zhong Zhao, Hai-quan Mao, Kam W. Leong
  • Patent number: 5952451
    Abstract: A process for making a high molecular weight poly(phosphoester) composition comprising:(i) a biologically active substance; and(ii) a poly(phosphoester) with the recurring monomeric units: ##STR1## wherein X is --O-- or --NR"--, where R" is H or alkyl; L is a divalent organic moiety, with the proviso that L cannot have the formula ##STR2## R' is H, alkyl, alkoxy, aryl, aryloxy, heterocyclic, or heterocycloxy; and n is from about 25 to 2000,is described. The process comprises the steps of:(a) substantially dissolving p moles of a di--XH compound in a solvent comprising more than 75% toluene at a first temperature between about -75.degree. C. and +60.degree. C. to form a reaction mixture;(b) while maintaining the reaction mixture at the first temperature, adding q moles, where p.apprxeq.q, of a phosphorodihalo compound;(c) gradually increasing said first temperature at a rate of less than about 1.5.degree. C. per minute as necessary to achieve a second temperature between about 0.degree. C. and 150.degree. C.
    Type: Grant
    Filed: June 23, 1998
    Date of Patent: September 14, 1999
    Assignee: Guilford Pharmaceuticals Inc.
    Inventor: Zhong Zhao