Drug delivery in a can

A student at Johns Hopkins University has developed tiny biodegradable plastic particles that could be used in an aerosol spray to carry DNA vaccines deep into human lungs.

A student at Johns Hopkins University has developed tiny biodegradable plastic particles that could be used in an aerosol spray to carry DNA vaccines and other medicines deep into human lungs.

The deep lung area, where oxygen enters the bloodstream, may be an effective entry point for DNA vaccines and other medications used to treat ailments ranging from cystic fibrosis to cancer.

Eric Krauland spent the summer of 2000 in a lab at Johns Hopkins, conducting experiments to produce drug-delivery vehicles, called cationic polymer microspheres.

Krauland began making the particles by forming nascent aerosol particles by emulsifying DNA-containing solutions into polymer-containing solutions.

Using freeze-drying equipment, he next removed the liquid, leaving behind hard polymer spheres that resemble a white powder. During this process, Krauland added a surfactant, a material that moved to the surface of the spheres, giving them a positive charge.

When they are mixed in a solution with dissolved DNA molecules, which have a negative charge, DNA clings to the surface of the particles.

More recently, Krauland has tinkered with his formula by changing mixing speeds, chemical concentrations and water-to-oil ratios. These variations are said to alter the size, density and surface charges of the particles.

Krauland’s goal is to produce microspheres that are light and do not stick together when shot out of an aerosol device. The spheres must be capable of carrying large molecules such as DNA and proteins deep into the lungs, where they can be released into the body over a prescribed period of time.

Krauland hopes to have results ready for submission to a peer-reviewed journal by the autumn of 2001and intends to seek a patent for his particles.