Volatile Acid-Solvent Evaporation (VASE): Molecularly Homogeneous Distribution of Acyclovir in a Bioerodable Polymer Matrix for Long-Term Treatment of Herpes Simplex Virus-1 Infections

Treatment for herpes simplex virus-1 and -2 (HSV-1 and -2) patients who suffer from recurrent outbreaks consists of multiple daily doses of the antiviral drugs acyclovir (ACV), penciclovir, or their more orally bioavailable derivatives valacyclovir or famciclovir. Drug troughs caused by missed doses may result in viral replication, which can generate drug-resistant mutants along with clinical sequelae. We developed a molecularly homogeneous mixture of ACV with the bioerodable polymer polycaprolactone. Through scanning electron microscopy, infrared spectroscopy, gel permeation chromatography, 1H NMR, and differential scanning calorimetry, our method of combining drug and polymer, termed Volatile Acid-Solvent Evaporation (VASE), does not compromise the integrity of polymer or drug. Furthermore, VASE creates materials that deliver therapeutic amounts of drug consistently for approximately two months. Devices with high enough drug loads diminish primary infection of HSV-1 in Vero cells to the same level as seen with a single dose of ACV. Our data will lead to further experiments in animal models, demonstrating efficacy in preventing reactivation of these viruses with a single intervention, and with other antiviral drugs amenable to such manipulation. Additionally, this type of treatment would leave no trace after its useful lifetime, as drug is released and polymer matrix is degraded in vivo.