Anti-AIDS Drug Becomes Ten Times Less Toxic

Outstanding antiviral action of multiple antibiotics remains unclaimed due to high drug toxicity. Russian physicians are trying to get nontoxic drug dosage form and have achieved success as regards to anit-AIDS antibiotic – Heliomycinum. Their effort has been funded by the International Science and Technology Center.

Specialists of the Lomonosov Moscow State Academy of Fine Applied Chemistry and Ivanovsky Scientific Research Institute of Virology (Russian Academy of Medical Sciences) have found the way to reduce by ten times toxicity of anit-AIDS antibiotic Heliomycinum (Resistomycinum). To this end, antibiotic was enclosed into an adipose (lipidic) bubble – liposome.

Utilization of liposomes as a carrier of drugs is increasingly attracts attention of researchers. Liposomes are non-toxic and get fully decomposed in the organism. As lipids’ disintegration occurs gradually, the drug enclosed in liposome is also released in small doses, thus allowing to create drugs with durable action and to reduce their toxicity.

Heliomycinum is one of the drugs whose toxicity the researchers are eager to reduce. This antibiotic blocks the action of several specific enzymes of human immunodeficiency virus, therefore, it has been considered a promising antiviral drug for a long time. However, Heliomycinum has not been widely accepted in medicine due to very poor solubility in water and high toxicity. Heliomycinum inclusion into liposomes would improve the drug quality and allow to create its injection form of low toxicity.

To obtain a liposomic drug, the researchers added the Heliomycinum solution in the chloroform and methanol mixture to the lipidic film. Samples were frozen in liquid nitrogen and stirred up at room temperature. The freezing/thawing cycle was repeated for five more times. As a result, antibiotic embedded into the lipidic film. Then, the mixture was forced through the filters with small interstices to separate non-bound Heliomycinum, and the medicinal mixture itself was smashed to small bubbles containing known concentration of antibiotic. The researchers sorted out such lipid composition that up to 97 percent of Heliomycinum is included into liposomes. Having hidden Heliomycinum into liposomes, the researchers succeeded to dissolve it in physiological solution, which is important for pharmaceutical purposes.

The liposome drug toxicity was tried on the culture of embryonic fibroblasts. Heliomycinum in aqueous solution destroyed every single cell already within 24 hours, and toxicity of liposomic form turned out to be ten times lower. Antiviral activity of liposomic Heliomycinum was tried on the culture of fibroblasts which were infected by cytomegalovirus. This human virus does not cause diseases and ideally fits for model experiments. A new drug has turned out to be active against virus, the drug being applied in such concentration that it is non-toxic for cells.