Electrochemical behavior and analytical application of acyclovir using a β-Cyclodextrin / TiO2 nanoparticles composite film- carbon paste electrode

Acyclovir (ACV) is a synthetic deoxyguanosine analog. ACV is widely used in treatment of herpes simplex, herpes zoster infections, primary genital herpes, herpetic encephalitis, and varicella zoster virus infections in immunosuppressed patients. It is also helpful in inhibiting HSV infections in renal allograft receptors and its anti-hepatitis B virus activity has been demonstrated [1, 2]. ACV may lead to nephrotoxicity (crystallization of ACV within renal tubules, enhancement of serum creatinine, transient), and neurotoxicity [3]. Based on above description the quantitative determination of ACV become very important. In this work we developed an accurate and sensitive sensor for electrochemical detection of ACV with a high-conductivity β-Cyclodextrin / TiO2 nanoparticles composite film modified carbon paste electrode (β-CD /TiO2 NPs-CPE). The surface and electrochemical characterization of the modified electrode was performed by field emission scanning electron microscopy, chronocoulometry, cyclic voltammetry and differential pulse voltammetry. A significant enhancement in the peak current response of ACV was observed accompanied with a negative shift in peak potential at the composite modified electrode compared to the unmodified electrode. The effective surface area (0.55 cm2) which is 5 times as much as that of the unmodified CPE, electron transfer coefficient (0.39) and number of electrons involved in the rate determining step (2.03) for ACV were also determined using electrochemical approaches. Under optimal conditions, the prepared β-CD /TiO2 NPs-CPE film exhibits excellent DPV response towards ACV and the peak current increased linearly with respect to ACV concentration in the linear range between 0.09 to 2.98 and 2.98 to 47.61 μM at physiological pH 7.0 with detection limit of 21 nM. Real sample analysis has been successfully carried out in blood serum sample, which revealed good recovery results, 97.2–102.3%. The proposed sensor also displayed good selectivity, repeatability and reproducibility with appreciable long-term stability.