STRUCTURE OF CHEMICAL COMPOUNDS, METHODS OF ANALYSIS AND PROCESS CONTROL HPLC DETERMINATION OF PURINE BASES POSSESSING ANTIHERPETIC ACTIVITY (A REVIEW)

Aciclovir, or 9-(2-hydroxyethoxymethyl)-9H-guanine, is an acyclic analog of the natural nucleoside 2-deoxyguanosine. For many years, aciclovir occupies the leading position in the group of drugs used for the treatment of infectious diseases caused by herpes simplex virus (HSV) of types 1 and 2. The mechanism of the antiherpetic action of aciclovir is based on the inhibition of viral DNA synthesis. Penetrating into an HSV-infected cell, aciclovir is converted by viral thymidine kinase into aciclovir monophosphate. Under the action of cell enzymes, this product is sequentially converted into acilovir diphosphate and triphosphate. Aciclovir triphosphate is capable of selectively blocking the assembly of viral DNA while practically not influencing the replication of human cell DNA. A disadvantage of aciclovir is the low bioaccessibility of the parent compound with respect to peroral administration. Various methods are used for increasing the bioaccessibility of this drug in various medicinal forms: (i) The formation of aciclovir esters [1 – 5]. Valaciclovir, representing aciclovir valine ester, is well absorbed in the organism upon peroral administration and metabolized with