A nanoformulation of a photosensitive molecule and a chemiluminescent substrate that acts as a molecular flashlight to activate the photosensitive molecule to kill HIV inside the body

Antiviral Drug Development Difficulties

The development of new antiviral agents is an important and difficult task. In general, compared to other classes of anti-infectives, there are far fewer drugs available in the field of antiviral therapy. The difficulties of developing antivirals result, in part, from viral replication taking place inside the infected cell while utilizing the cell’s molecular machinery.

Some viral diseases are virtually untreatable (Hepatitis C, hemorrhagic fevers induced by flaviviruses, Ebola, Lassa, and related viruses). Moreover, a number of new and emerging viral agents (HIV, West Nile, Hantavirus and Influenza [H5N1]) have either entered or are threatening to enter the human population, some of which have caused or can cause serious epidemics and pandemics.

Shedding Light on The Problem

Currently, there are no drugs that are generally effective against different viral agents. Several compounds with broad antiviral activity have been reported, but none of them has attracted commercial development because of toxicity.

There is, however, one class of compounds that do not produce substantial toxicity while at the same time having strong antiviral activity; compounds in this class all require light to exert their virucidal activity. Such compounds include the light-sensitive plant pigment hypericin isolated from St. John’s Wort (Hypericum perforatum) and many chemically related compounds.

Hypericin Alone Is Ineffectual

The efficiency of hypericin-induced, light-mediated viral inactivation is so high that even relatively short exposure times, which occur during routine tissue culture infection procedures, were sufficient for nearly complete inactivation of the exposed virus, notably HIV and other retroviruses. In contrast, if a virus is treated with hypericin in complete darkness, then the virucidal effects are minimal, if at all detectable.

Obviously, one should not expect any benefits from hypericin administration to patients afflicted by viral diseases since there’s no light inside the organism. Despite this reasonable assumption, clinical studies of hypericin benefits for HIV and hepatitis C-infected individuals have been performed with the predictable negative result. These compounds do not work in the dark and thus, by themselves are not effective within the human body.

Chemiluminescence Is The Key

We have circumvented this limitation by coupling light-sensitive compounds such as hypericin with chemiluminescence generated by native enzymes such as alkaline phosphatase present in normal tissues within the body.

Additionally, we have enhanced antiviral efficacy by the addition of various anti-quenchers and wavelength-shifting compounds (US Patent).