Validation of high performance liquid chromatographic and spectrophotometric methods for the determination of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products

The antiparkinson agent pramipexole dihydrochloride monohydrate was quantified in pharmaceutical products by high performance liquid chromatography (HPLC) and derivative spectrophotometry. The first method was based on HPLC using tamsulosin HCl as an internal standard. In this method, chromatographic separation was achieved using a LiChrospher 60 RP column at 25°C, with a flow rate of 1.0 mL/min at 263 nm. The eluent comprised 0.01 mol/L ammonium acetate (pH 4.4) and acetonitrile (35:65 by volume). The linearity range was found to be 10.0-30.0 µg/mL with a mean recovery of 100.5 ± 1.10. The limit of detection (8 ng/mL) and limit of quantification (50 ng/mL) were calculated. In the second method, the first derivative spectrophotometric technique for the determination of pramipexole dihydrochloride monohydrate was performed by measuring the amplitude at 249 and 280 nm. In the first derivative technique, the absorbance and concentration plot was rectilinear over the 5.0-35.0 µg/mL range with a lower detection limit of 1.5 ng/mL and quantification limit of 4.5 ng/mL. The typical excipients included in the pharmaceutical product do not interfere with the selectivity of either method. The developed methods were validated for robustness, selectivity, specificity, linearity, precision, and accuracy as per the ICH and FDA guidelines (ICH Q2B, 1996; FDA,2000). In conclusion, the developed methods were successful in determining the quantity of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products. The RSD values for the pharmaceutical product used in this study were found to be 0.97% for the HPLC method and 0.00% for the first derivative spectrophotometric method.O fármaco antiparkinsoniano, dicloridrato de pramipexol monoidratado, foi quantificado no produto farmacêutico por cromatografia líquida de alta eficiência (CLAE) e espectrofotometria derivada. No primeiro método baseado na CLAE, o cloridrato de tansulosina foi usado como padrão interno. Nesse método, a separação cromatográfica foi realizada usando uma coluna Lichrosper 60 RP a 25 °C e acetato de amônio 0,01 mol/L (pH:4.4): acetonitrila (35:65 em volume) como eluente com fluxo de 1,0 mL /min a 263 nm. A faixa de linearidade foi de 10.0-30.0 µg/mL com média da recuperação 100.5 ± 1.10. O limite de detecção (8 ng/mL) e o limite de quantificação (50 ng/mL) foram calculados. Por outro lado, a primeira técnica de espectrofotometria derivada para a determinação de dicloridrato de pramipexol monoidratado foi realizada através da medida da amplitude a 249 e 280 nm. Na técnia da primeira derivada, a absorvância e a plotagem da concentração foi retilínea na faixa de 5.0-35.0 µg/mL com limite inferior de detecção de 1.5 ng/mL e limite de quantificação de 4.5 ng/mL. Os excipientes típicos incluídos no produto farmacêutico não interferem com a seletividade dos métodos. Os métodos desenvolvidos foram validados quanto à robustez, seletividade, especificidade, linearidade, precisão e exatidão de acordo com as diretrizes do ICH e FDA (ICH Q2B,1996; FDA,2000). Concluindo, os métodos propostos foram aplicados com sucesso para a determinação quantitativa do agente antiparkinsoniano dicloridrato de pramipexol monoidrato em produtos farmacêuticos. Os valores de RSD para o produto farmacêutico utilizado neste estudo foi 0.97% para a CLAE e 0.00% para o método de espectrofotometria de primeira derivada

Construction of a simple and selective electrochemical sensor based on Nafion/TiO2for the voltammetric determination of olopatadine

A selective and facile voltammetric method based on titanium dioxide nanoparticles and Nafion (Nafion/TiO2NPs) on the screen-printed electrode (SPE) was proposed forolopatadinedetermination. Followed by the synthesis of TiO2nanoparticles, various methods, including high-resolution transmission electron microscopy (HR-TEM), ultraviolet-visible spectroscopy (UV-Vis),energy-dispersive X-ray (EDX) Raman spectrum, and electrochemical impedance spectroscopy (EIS) wereutilized tocharacterize the nanomaterials. Nafion/TiO2on the screen-printed electrode (NFN/TiO2/SPE) was used to determine olopatadine in concentration ranges of 0.01 to 0.07 and 0.07 to 14.6 μM with a limit of quantification as low as 7.0 nM, via differential pulse voltammetry technique. The NFN/TiO2/SPE offered a high-performance ability to determine olopatadine in the eye drop sample with satisfactory recovery data of 98.2–99.0 %. Also, the developed electrode showed good reproducibility, repeatability, and high selectivity features. The obtained results indicate that NFN/TiO2/SPE could be utilized as an appropriate candidate for electrochemical olopatadine sensing

A sensitive voltammetric sensor for specific recognition of vitamin C in human plasma based on MAPbI3perovskite nanorods

A novel and sensitive electrode was suggested for the rapid determination of ascorbic acid (AA) using a glassy carbon electrode (GCE) modified with synthesized MAPbI3and L-cys (L-cys/MAPbI3/GCE). Determination of ascorbic acid as an important component of the human diet due to help in decreasing blood pressure and improving endothelial function is crucial. The synthesized MAPbI3was characterized by different methods, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The fabricated electrode exhibited superior electrical conductivity and fast electron transfer kinetics. The results illustrated that the developed electrode had an outstanding electrocatalytic activity towards the oxidation of AA in0.1 MBritton–Robinson buffer(B-R) as a supporting electrolyte. The modified electrodedemonstrated a linear range in differential pulse voltammetry of 0.02–11.4 μM with a low detection limit of 8.0 nM for ascorbic acid. It can be stated that the proposed sensor can be successfully applied to the determination of ascorbic acid in human plasma samples

Electrochemical Sensing of Favipiravir with an Innovative Water-Dispersible Molecularly Imprinted Polymer Based on the Bimetallic Metal-Organic Framework: Comparison of Morphological Effects

Molecularly imprinted polymers (MIPs) are widely used as modifiers in electrochemical sensors due to their high sensitivity and promise of inexpensive mass manufacturing. Here, we propose and demonstrate a novel MIP-sensor that can measure the electrochemical activity of favipiravir (FAV) as an antiviral drug, thereby enabling quantification of the concentration of FAV in biological and river water samples and in real-time. MOF nanoparticles’ application with various shapes to determine FAV at nanomolar concentrations was described. Two different MOF nanoparticle shapes (dodecahedron and sheets) were systematically compared to evaluate the electrochemical performance of FAV. After carefully examining two different morphologies of MIP-Co-Ni@MOF, the nanosheet form showed a higher performance and efficiency than the nanododecahedron. When MIP-Co/Ni@MOF-based and NIP-Co/Ni@MOF electrodes (nanosheets) were used instead, the minimum target concentrations detected were 7.5 × 10−11 (MIP-Co-Ni@MOF) and 8.17 × 10−9 M (NIP-Co-Ni@MOF), respectively. This is a significant improvement (>102), which is assigned to the large active surface area and high fraction of surface atoms, increasing the amount of greater analyte adsorption during binding. Therefore, water-dispersible MIP-Co-Ni@MOF nanosheets were successfully applied for trace-level determination of FAV in biological and water samples. Our findings seem to provide useful guidance in the molecularly imprinted polymer design of MOF-based materials to help establish quantitative rules in designing MOF-based sensors for point of care (POC) systems

Electrochemical Sensing of Favipiravir with an Innovative Water-Dispersible Molecularly Imprinted Polymer Based on the Bimetallic Metal-Organic Framework: Comparison of Morphological Effects

Molecularly imprinted polymers (MIPs) are widely used as modifiers in electrochemical sensors due to their high sensitivity and promise of inexpensive mass manufacturing. Here, we propose and demonstrate a novel MIP-sensor that can measure the electrochemical activity of favipiravir (FAV) as an antiviral drug, thereby enabling quantification of the concentration of FAV in biological and river water samples and in real-time. MOF nanoparticles' application with various shapes to determine FAV at nanomolar concentrations was described. Two different MOF nanoparticle shapes (dodecahedron and sheets) were systematically compared to evaluate the electrochemical performance of FAV. After carefully examining two different morphologies of MIP-Co-Ni@MOF, the nanosheet form showed a higher performance and efficiency than the nanododecahedron. When MIP-Co/Ni@MOF-based and NIP-Co/Ni@MOF electrodes (nanosheets) were used instead, the minimum target concentrations detected were 7.5 x 10(-11) (MIP-Co-Ni@MOF) and 8.17 x 10(-9) M (NIP-Co-Ni@MOF), respectively. This is a significant improvement (>10(2)), which is assigned to the large active surface area and high fraction of surface atoms, increasing the amount of greater analyte adsorption during binding. Therefore, water-dispersible MIP-Co-Ni@MOF nanosheets were successfully applied for trace-level determination of FAV in biological and water samples. Our findings seem to provide useful guidance in the molecularly imprinted polymer design of MOF-based materials to help establish quantitative rules in designing MOF-based sensors for point of care (POC) systems

Innovative molecularly imprinted electrochemical sensor for the nanomolar detection of Tenofovir as an anti-HIV drug

© 2022 Elsevier B.V.Tenofovir (TNF) is an antiviral medicine that is utilized to treat the human immunodeficiency virus (HIV). However, its level must be controlled in the human body and environment at the risk of causing kidney and liver problems. Therefore, determining TNF concentration in real samples with more advanced, inexpensive, and accurate sensing systems is essential. In this work, a novel electrochemical nanosensor for TNF determination based on molecularly imprinted polymer (MIP) on the screen-printed electrode modified with functionalized multi-walled carbon nanotubes, graphite carbon nitride, and platinum nanoparticles (MIP-Pt@g-C3N4/F-MWCNT/SPE) was constructed through the electro-polymerization approach. The molecularly imprinted polymers were prepared on the electrode surface with TNF as the template molecule and 2-aminophenol (2-AP) as the functional monomer. Moreover, factors that affect sensor response were optimized. Pt@g-C3N4/F-MWCNT nanocomposite had an excellent synergistic effect on MIP, allowing rapid and specific identification of the test substance. The results demonstrated that the electro-polymerization of 2-AP supplies large amounts of functional groups for the binding of the template molecules, which remarkably enhances the sensitivity and specific surface area of the MIP sensor. This surface enlargement increased the analyte accessibility to imprinted molecular cavities. Under optimum conditions, the oxidation peak current had a linear relationship with TNF concentration ranging from 0.005 to 0.69 μM with a low detection limit of 0.0030 μM (S/N = 3). The results demonstrated that the designed MIP sensor possesses acceptable sensitivity, repeatability, and reproducibility toward TNF determination. Moreover, the developed sensor was applied to biological and water samples to determine TNF, and satisfactory recovery results of 95.6–104.8% were obtained (RSD less than 10.0%). We confirm that combining as-synthesized nanocomposite Pt@g-C3N4/F-MWCNT with MIP improves the limitations of MIP-based nanosensors. The proposed electrode is also compatible with portable potentiostats, allowing on-site measurements and showing tremendous promise as a point-of-care (POC) diagnostic platform

Construction of a novel sensor based on activated nanodiamonds, zinc oxide, and silver nanoparticles for the determination of a selective inhibitor of cyclic guanosine monophosphate in real biological and food samples

In the present work, we developed a highly sensitive and selective method for the determination of sildenafil (SIL) using a modified glassy carbon electrode (GCE) with activated nanodiamonds, zinc oxide, and silver nanoparticles nanocomposite (AND@ZnO-Ag/GCE). Various voltammetric techniques, including CV, DPV, and EIS, were employed to investigate the electrochemical process of SIL on the modified electrode. The resulting AND@ZnO-Ag/GCE electrode exhibited enhanced electron transfer between the electrode and the analyte, resulting in an excellent electrocatalytic performance for SIL oxidation under optimized conditions. The analytical performance of the AND@ZnO-Ag/GCE sensor demonstrated two linear responses within the concentration range of 0.01–0.08 μM and 0.08–14.6 μM, with a remarkably low detection limit of 7.08 nM. Moreover, the modified sensor (AND@ZnO-Ag/GCE) exhibited high selectivity and anti-interference capacity. It successfully detected trace amounts of SIL in biological and food samples, yielding satisfactory results. Furthermore, this work provides insights into the potential adulteration of energy drinks with sildenafil, addressing an area that has received limited attention in previous research