Novel therapeutic biosensor for indinavir—A protease inhibitor antiretroviral drug

An amperometric drug metabolism biosensor consisting of cytochrome P450-3A4 (CYP3A4) encapsulated in a didodecyldimethylammonium bromide (DDAB) vesicular system on a Pt disk electrode was developed for the determination of indinavir, a protease inhibitor antiretroviral drug. Cyclic, square wave and pulse voltammetric responses of the bioelectrode showed quasi-reversible electrochemistry of the Fe³⁺/Fe²⁺ redox species of the heme thiolate CYP3A4 enzyme under aerobic and anaerobic conditions. The biosensor exhibited excellent response to indinavir with a detection limit and response time of 6.158 × 10⁻² mg L⁻¹, and 40 s, respectively. The detection limit is well below the plasma concentration of indinavir (8 h after intake) which range from 0.13 to 8.6 mg L⁻¹.