WASHINGTON -- The Liposome Co. on Tuesday was awarded aU.S. patent covering a broad category of multilamellarliposomes.

The patent covers the first viable technique for large-scaleproduction of multilamellar liposomes, said Marc Ostro, vicechairman and chief science officer at the Princeton, N.J.,company. In addition, he said, the company has improved thestability of multilamellar liposomes

Drugs are dissolved in the compartments of the liposomes fordelivery to disease sites. Multilamellar liposomes havemultiple layers. Another liposome form, unilamellar, is asmaller molecule with one bilayer.

The patent, No. 5,030,453, also covers therapeutic substancesencapsulated in the liposomal vehicle, as well as non-pharmaceutical materials such as cosmetics.

The company's stock (NASDAQ:LIPO) closed at $9, down 13cents, on Tuesday.

The company's TLC G-65, which is in Phase II trials forMycobacterium avium-intracellulare (MAI) in AIDS patients, isthe only multilamellar liposome product in clinical trials. Itcontains gentamicin, an aminoglycoside antibiotic, and iscovered by the patent.

The patent "offensively protects TLC G-65, providing anotherlayer of protection" on top of other patents and the drug'sorphan status, according to Ostro. "Defensively, it also createsa fence around a whole class of liposomes which have a lot ofother applications," he said.

Several other companies, including Liposome Technology Inc.(NASDAQ:LTIZ) and Vestar Inc. (NASDAQ:VSTR), are developingliposomal products.

Liposome Co.'s patent on multilamellar liposomes "does notintersect our technologies," according to Paul Schmidt, vicepresident of research and development at Vestar. "We'vedifferentiated ourselves in this area in that our emphasis is onthe small, unilamellar liposomes. We did this in part becauseof (the Liposome Co.'s) demonstrated advantages in the largerliposomes," Schmidt said.

-- Steve Usdin BioWorld Washington Bureau

(c) 1997 American Health Consultants. All rights reserved.