RESULTS
The MEPS experiment
on the International
Space Station consisted
of 8 samples processed
using various methods
to mix dissimilar liquids
to form micro-
balloons/microcapsules.
The recovered micro-
balloons were analyzed
for size and drug
content. Additionally,
studies included the
effects of temperature
and mixing fluid shear
on the size of the micro-balloons and payload concentration of contrast and concentrated drug.
ON UF-2 several combinations of anti-cancer drugs, photodynamic therapy drugs, and a DNA
construct were successfully encapsulated. These results led to the invention and NASA Patent
for a Pulse Flow Microencapsulation Processing System that has been used to make these
microcapsules for ground-based studies on human tumors grown in a mouse model. Pre-clinical
investigations revealed that when only a few doses of microcapsules containing 5-Fluorouracil
are injected directly into human prostate tumors, the growth can be inhibited by up to 51%
within 3 weeks. When chemotherapy microcapsules are injected following cryo-surgery, the
combined treatment can greatly inhibit the growth of 1-2cm size prostate tumors by 72% in just
3 weeks (Morrison 2009). Other studies using 2 doses of 5-FU microcapsules injected into A549
human lung tumors inhibited growth by 45% and destroyed 18% of the lung tumors after 4
weeks of sustained release. In a parallel study, only 2 doses injected of microcapsules
containing Paclitaxel, injected on Day 0 and Day 7 produced macroscopic necrosis in 43% of the
tumors. After 26 days of sustained Paclitaxel release, lung tumor growth was inhibited by 82%
and 28% of the tumors had completely disappeared (Morrison 2013, in press).
A further study was carried out aiming to confirm the increased growth inhibition of human
prostate tumors produced by an intentionally palliative combination treatment of
cryochemotherapy (partial cryoablation followed by intratumor partial chemotherapy with
injection of microencapsulated 5-fluorouracil at the ice ball periphery). The results of this study
extend and confirm previous findings (Le Pivert 2009). The addition of 5-fluorouracil focal
chemoablation to partial cryoablation of a fast growing hormone resistant prostate cancer
enhances the directional destructive effect of cryosurgery and inhibits growth in peripheral
unfrozen tumor tissues (Le Pivert 2004 ).
The images shows some microcapsules produced on the International Space
Station in Microencapsulation Electrostatic Processing Systems during the UF-2
mission (July 18-19,2002). NASA Johnson Space Center image.