US4994281A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polylactic acid microspheres and process for producing the same
Assignee: Biomaterials Universe Inc
•
Filing: 1987-11-10
•
Granted: 1991-02-19
•
Expires: 2007-11-10
Abstract
Abstract Polylactic acid microspheres having an average particle diameter of about 0.1 to 10 μm which are produced from solution containing a physiologically active substance by the solvent-evaporation drying process. The microspheres are produced by emulsifying the solution in a non-solvent by the aid of ultrasonic wave. The microspheres produce a sustained release effect of the physiologically active substance.
Inventors
- 👤 Shozo Muranishi
- 👤 Yoshito Ikada
- 👤 Hiroshi Yoshikawa
- 👤 Shokyu Gen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:19
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/48; A61K9/50; A61K9/51; A61K9/5107; A61K9/513; A61K9/5146; A61K9/5153; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1641; A61K9/1647; A61K9/1682; A61K9/1694; A61K9/5192
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
80 words
A method of enhancing phagocytosis during the controlled sustained release of a physiologically-active substance in a pharmaeutical preparation comprising administering to a host an effective amount of a pharmaceutical preparation comprising spherical microspheres of polylactic acid, said microspheres having entrapped therein said physiologically-active substance, and utilizing said microspheres in a form having an average particle diameter of 1 to 2 μm to enhance phagocytosis as said physiologically-active substance is being released from said microspheres in a sustained manner over time.
Claim 2
Independent Claim
80 words
A method of enhancing phagocytosis during the controlled sustained release of a physiologically-active substance in a pharmaeutical preparation comprising administering to a host an effective amount of a pharmaceutical preparation comprising spherical microspheres of polylactic acid, said microspheres having entrapped therein said physiologically-active substance, and utilizing said microspheres in a form having an average particle diameter of 1 to 2 μm to enhance phagocytosis as said physiologically-active substance is being released from said microspheres in a sustained manner over time.
Claim 3
Dependent Claim
14 words
A method as in claim 1, wherein said physiologically-active substance is an anticancer drug.
Claim 4
Dependent Claim
44 words
A method as in claim 2, wherein said pharmaceutical preparation comprises a solution having said microspheres suspended therein, and wherein said pharmaceutical preparation is administered to said host intraperitoneally, whereby said microspheres provide a directionality of said anticancer drug toward lymph in said host.
Claim 5
Dependent Claim
26 words
A method as in claim 1, wherein said physiologically-active substance has a concentration of 5 to 25% w/w based on the amount of said polylactic acid.
Claim 6
Dependent Claim
18 words
A method as in claim 1, said polylacitic acid having a molecular weight of about 3000 to 7500.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-18 | 1994-08-20 | 1995-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-18 | 1998-08-20 | 1999-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-18 | 2002-08-20 | 2003-02-19 | $7700.00 | Window Closed / Lapsed |