ESA Analytical has produced an application note that describes a method using isocratic HPLC with electrochemical array detection, for measuring acyclovir in human plasma
Acyclovir is an antiviral drug used in the treatment of human viruses, such as herpes simplex types 1 and 2, the varicella-zoster virus (chicken pox and shingles) and has been prescribed for and used by people with HIV infection.
Unlike alternative methods which suffer from poor sensitivity (HPLC-UV), operating conditions which lead to poor reproducibility (HPLC-fluorescence) or difficulty in obtaining the specific monoclonal antibody (Elisa) the electrochemical array detection method described is simple, reliable and sensitive to low picogram levels.
The new ESA method uses a simple protein precipitation step, which gives nearly 100% extraction efficiency eliminating the need for an internal standard.
Chromatograms for extracted plasma and spiked plasma illustrate a peak for Acyclovir at 7.2 minutes clear of any interferences.
Using ESA's CoulArray electrochemical detector for HPLC provides the superior sensitivity and selectivity required for measuring low picogram levels of anti-viral drugs in human plasma.
Compared with techniques such as photodiode array UV detection, coulometric array detection gives typically three orders of magnitude better sensitivity.
