SPACE PRODUCT DEVELOPMENT EXPERIMENTS

Microencapsulation Electrostatic
Processing System

Objectives: In the future multi-layer microcapsules may hold the key to improving techniques of drug delivery during chemotherapy treatment, and researchers from the Institute for Research, Inc. in Houston, Texas, and NASA Johnson Space Center will use a new commercial payload -- the Microencapsulation Electrostatic Processing System (MEPS) -- to produce capsules for evaluation. The experiment is sponsored by NASA's Space Product Development Office of the Microgravity Research Program at the Marshall Space Flight Center in Huntsville, Ala.

A multi-layer capsule not only holds a dose of an FDA-approved anti-tumor drug, but also can hold a radio-trace medium. This will allow doctors to X-ray and monitor the accumulation and distribution of the capsules in the tumor to be sure that all regions of the tumor receive optimum treatment.

Microencapsulation Electrostatic Processing experiments conducted during STS-95 will include three specific manufacturing objectives:

• Study the formation of anti-tumor capsules containing two kinds of drugs
• Micro-encapsulate a photo-activated drug which, when exposed to red light, will destroy surrounding tumors
• Apply Electrostatic coating to anti-tumor capsules containing powerful chemotherapy drugs (Cis-Platinum & Floxuridine, Floxuridine & Levamisole, and Cis-Platinum & Photofrin) with a substance that resists attack by the body's immune system and increases its ability to destroy specific tumors.

Description: For many cancer patients, chemotherapy is one of the most feared parts of treatment because it can be so debilitating. With large, solid tumors, however, a special type of chemotherapy currently in use is called transcatheter chemoemobilization. In this process, the chemotherapy -- approximately five percent of the "normal" dose -- is placed directly into the tumor through a catheter in one of the many blood vessels that serve the tumor followed by an injection of GelfoamTM particles. These particles then swell to block the blood vessels in and around the tumor so that the treatment does not prematurely "wash out" of the tumor. Using this chemotherapy technique has improved the one-year survival rate of patients with non-operable liver tumors from 18 percent to between 55 and 69 percent, and reduced undesirable side effects.

The experiment facility will automatically control fluid flows, record video of fluid interfaces as the microcapsules are formed, harvest the capsules and use electrostatic deposition of a thin coating of an ancillary polymer.

The facility will process six research runs during the mission. Each run is contained in a Process Chamber Module that will activated by the crew, and removed and stored after each two-hour run. The data gathered during this effort will evaluate the performance of the system, and advance the production of multi-layer microcapsules on Earth.