There was a time in medicinal history when activated charcoal was considered the universal antidote. Since then it has been touted to reduce flatulence, prevent hangovers, and lower cholesterol. Its effectiveness at neutralizing ingested poisons or medication overdoses is well established, but less so is activated charcoal’s ability to increase the efficacy of certain drugs. Now, investigators at the University of Illinois at Chicago have found that combining acyclovir—a commonly prescribed topical herpes medication—with particles of activated carbon improves the drug’s effectiveness.
This new approach allows for less frequent dosing and overall course of treatment while providing some protection from infection by the virus as well, opening the possibility of using the combination in prophylactic products. Findings from the new study were published recently in Science Advances through an article entitled “Drug-encapsulated carbon (DECON): A novel platform for enhanced drug delivery.”
“Combing herpes medication with activated charcoal makes the drug much more efficient so less of the drug is needed to achieve the same effect,” explained senior study investigator Deepak Shukla, PhD, professor of ophthalmology, microbiology, and immunology in the UIC College of Medicine. “Using less of the drug can help reduce the risk of kidney damage, which can be significant when these drugs are used over long periods of time.”
There are two types of herpes simplex virus: herpes simplex 1, which infects the eyes and mouth and is a leading cause of blindness, and herpes simplex 2, a genital infection that causes warts and can seriously impair quality of life.
Moreover, treatment for both infections often includes acyclovir—a systemic medication taken orally. However, long-term use often results in resistance to the drug as well as kidney damage. Activated carbon is known to have purifying effects by trapping toxins in its highly porous structure. Particles tend to bind to charcoal easily and it is often used in filters for water for this reason.
“In our quest to inhibit herpes simplex virus infection via the compounds found in commonly used cosmetic products, we found that activated carbon particles inhibit infection and, in addition, substantially improve topical delivery and, hence, the efficacy of a common antiviral drug, acyclovir (ACV),” the authors wrote. “Our in vitro studies demonstrate that highly porous carbon structures trapped virions blocked infection and substantially improved efficacy when ACV was loaded onto them. Also, using murine models of corneal and genital herpes infections, we show that the topical use of drug-encapsulated carbon (DECON) reduced dosing frequency, shortened treatment duration, and exhibited higher therapeutic efficacy than currently approved topical or systemic antivirals alone.”
The research team looked at the effect of both plain activated carbon and activated carbon plus acyclovir on HSV-1 and HSV-2. Dilutions of plain activated carbon were able to reduce the infection of cells in the lab when applied to the cells prior to exposure to HSV-1 or HSV-2. The scientists saw a 4% to 60% reduction in infections compared with when they exposed the cells to the virus without activated carbon present.
When they combined acyclovir with activated carbon and tested the mixture in mice infected with either HSV-1 or HSV-2, applying it to either the eyes or genitals, they saw that it was more effective and faster at reducing inflammation and viral load than topical or systemic acyclovir alone. Additionally, they found that the drug seemed to be working much more efficiently when combined with activated carbon, and they could achieve the same reductions in viral load and inflammation using far fewer doses than with acyclovir alone.
“We think that the charcoal releases particles of acyclovir slowly over time because the herpes virus, as well as other organic molecules and particles, are more attracted to the charcoal than the drug, and as these particles interact with the charcoal they displace and release the drug,” noted lead study investigator Tejabhiram Yadavalli, PhD, a postdoctoral fellow studying herpes viruses at UIC and a co-inventor of the technology. “The activated carbon acts like a slow-release drug capsule. Because it likes to bind with the virus, this gives it additional anti-viral properties.”
The researchers were excited by their findings and call the new charcoal delivery system DECON for Drug Encapsulated Carbon.
“Activated carbon is known to be safe for use by humans and has been used for thousands of years for its purifying properties. We think that using it as a novel drug delivery system could help reduce dosing, cost, and risk of toxicity to the kidneys and could eventually be used in lubricants prophylactically to help prevent new HSV genital infection,” Shukla concluded.