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A computational approach was developed to find a suitable functional monomer to design a new molecularly imprinted polymer (MIP), based on which methacyrlic acid (MAA) was selected as a functional monomer to synthesize the molecular imprinted and non‐imprinted polymers. All calculations were carried out using Gaussian 03 software based on the application of Hartree−Fock (HF) method with 6‐31G (d) basis set. The performance of the MIPs prepared with different ratios of MAA was then evaluated using equilibrium rebinding assays. The MIP with the highest binding capacity was chosen as recognition material for the fabrication of new PVC sensors and their responses were compared with each other and with previously reported modifiers in literature. The addition of the ionic surfactant (TFPB) was found to have a synergistic effect on the response mechanism of the electrodes. The results of the MIP modified sensors show that they provide an improved electrode slope, wider pH range and a highly extended life time reaching 7 months compared to 2–4 weeks in case of traditional ion‐exchangers reported in literature, besides, being successfully applied for measurements in biological samples.

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Ivabradine hydrochloride (IVR) is a medically important drug because of its ability to lower the heart rate. Techniques reported for IVR determination were expensive, laborious, besides being of poor selectivity. In this study, iron oxide @ carbon nanotube (Fe2O3@MWCNTs) nanocomposite and molecularly imprinted polymer (MIP) were synthesized and used in the fabrication of carbon paste electrodes (CPEs) for the potentiometric detection of IVR in biological and pharmaceutical samples. CPEs of the best sensor were formulated from graphite (41 wt%) as a carbon source, MIP (3 wt.%) as an ionophore, Fe2O3@MWCNTs (5 wt%) as a modifier, and nitrophenyl octyl ether (NPOE, 51 wt.%) as a conductive oil so-called plasticizer. The best sensor exhibits a Nernstian slope (response) of 56 mV decade–1 within the IVR concentration range from 1.0 × 10–3 M to 9.8 × 10–8 M with high selectivity against interfering species (ascorbic, maltose, glucose, lactose, dopamine, glycine) over those reported earlier. The use of Fe2O3@MWCNTs together with MIP in the electrode formulation was found to improve the limit of detection (LOD) from 630 to 98 nM along with high reversibility, a short response time of 30 s, and a good lifetime of more than 2 weeks. The sandwich membrane (SMM) method was used to quantify the H-bonding complexing strength of the MIP binding sites for IVR with Log βILn = 11.33. The constructed sensors were successfully applied for the IVR determination in blood serum, urine, and commercial formulations (Savapran®) with high sensitivity.

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A molecularly imprinted polymer (MIP) was rationally synthesized with the aid of computer based studies. The computational studies were used to screen for the most suitable template to functional monomer molar ratio. Two functional monomers were involved in the study (methacrylic acid and 4‐vinylpyridine). Four MIP ratios were synthesized in accordance with the results of the computational studies and their performance was evaluated using equilibrium rebinding assays. The MIP with the best performance was used as an additive in carbon paste electrodes for the voltammetric determination of valaciclovir (VCV). Following the optimization of voltammetric parameters, a linear response was obtained in the range of 1.0x10−6–7.0x10−4 M with a limit of detection at 4.45x10−7 M. The MIP modified carbon paste electrode was successfully applied for the determination of VCV in pure solutions and dosage form.

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