Rusian Science News

Source: www.informnauka.ru/eng

NANOSOMAL DRUG FORMS - NEW POTENTIAL OF KNOWN SUBSTABCES

01/15/2009

Russian researchers are developing drug forms that can significantly
improve the action of known substances. The finest particles of an
innocuous polymer enable to increase the drug efficiency, to reduce its
toxicity, and if necessary, to deliver the drug into the brain.
 
Further information: Svetlana Gelperina, Ph.D. (Chemistry), Director for
Science, “Scientific-Production Complex Nanosystem” Ltd., Moscow, Tel: + 7
(495)-679-8733, Svetlana.gelperina@gmail.com 

The nanotechnologies forum, which has recently taken place in Moscow,
introduced the work entitled «Nanosomal drug forms – new potential of known
substances". The results presented by Svetlana Gelperina, Ph.D.
(Chemistry), Director for Science, "Scientific-Production Complex
Nanosystem” Ltd., aroused interest of colleagues - chemists and
pharmaceutists. The outcomes obtained by specialists of the company and
their colleagues from Russia and Germany prove clearly: the offered
technology does allow not only to increase efficiency and to reduce
toxicity of drugs but also to develop new drug forms for "inconvenient"
substances.

Nanoparticles can help to produce, for example, intravenous drug forms for
the substances practically insoluble in water. It is common knowledge that
more than a half of compounds that potentially possess excellent
pharmacologic properties do not become drugs just because they poorly
dissolve in water.

The opportunities that can be provided by utilization of such drug forms
have been demonstrated by the authors by the example of well-known
substances applied in treatment of various diseases. These are the
antitumor antibiotic doxorubicine, antibiotics recommended for treatment of
tuberculosis - rifampicin and rifabutin, the preparation for fighting
alcoholic dependence - disulfiram. 

For each of them, the own nanosomal drug form was developed, which is able,
as had been proved by the experiments carried out in vitro and in vivo, to
solve the problems that are inevitable if medical practice uses traditional
drug forms of these compounds.

The technology is based on the concept of "address delivery" of the active
ingredient with the help of the so called polymeric nanoparticles, globules
with a diameter less than a micron, made of non-toxic polymers. The drug
substance is introduced into the organism in the "transportation facility",
the functions of which are performed by polymeric nanoparticles. At that,
the properties of the substance itself do not change fundamentally – its
molecules are simply traveling in the polymeric particles matrix like
people in a tram. However, the distribution of such nanoparticles in the
organism is different from than in a free substance, the distribution is
manageable.

In the course of time, the polymer decomposes in the organism, the drug
combined with the particles releases gradually, non-uniformly across the
entire organism but predominantly in the target organ – the lungs, which
are rich in macrophages, the liver and spleen – which is particularly
important in treatment of tuberculosis. Therefore, efficiency of
antituberculous antibiotics combined with nanoparticles of specially
selected composition, is higher than that of traditional ones. In the
organism, nanoparticles practically follow the way of tubercule bacilli –
the former and the latter get into macrophages, where the pathogenic
organism finds itself "face to face" with the drug that is sufficient to
cope with harmful bacteria.

By using the nanoparticles developed by the authors, it is possible to
"pull" the drug into the area where it would not get otherwise, for
example, into the brain protected from penetration of "unallowed"
substances by the so-called hematoencephalic barrier. This is necessary in
treatment of brain tumors – the most efficient antitumoral preparations
either fail to get through this barrier or do not practically dissolve in
water. Nanoparticles ensure drug delivery to the tumor.

The researchers have proved that the nanosomal drug form developed by them
enables to reduce toxicity of doxorubicine, which is by itself very
efficient in struggling against tumors, including brain tumors, but it
practically does not get from the bloodstream into the brain and results in
heavy lesions of the heart and testicles. The drug combined with
nanoparticles works more efficiently – the tumor diminished significantly
with part of laboratory animals, and it disappeared entirely with other.
Such nanosomal doxorubicine causes much less damage to the heart and
testicles. So far, all the above has been shown only in experiments on
rats, however, the data presented in the report is very convincing. 

The investigation is being carried out by the researchers in cooperation
with their colleagues from the Institute of Human Morphology (Russian
Academy of Medical Sciences), the G.F. Gause Research Institute of New
Antibiotics (Russian Academy of Medical Sciences), the Goethe Institute of
Pharmaceutical Technology, Frankfurt am Main, Germany.

While such drug forms are going thought the stage of development and tests
on animals, clinical trials are still several years ahead. However, it is
clear already that the technology does work and its potential is enormous.

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