The quality of pharmaceutical products is critical for human health. Drug development requires tools to assess the presence of degradation products and contaminants during the manufacturing and storage processes. Accelerated stress degradation and kinetic studies play a vital role in predicting final product stability. This work describes the design of potentiometric sensor based on copper microfabricated electrodes for in‐line tracking the degradation kinetics of neostigmine. The proposed electrochemical technique provides a continuous profile for the hydrolysis of NEO under different temperatures and pH. The hydrolysis activation energy was found to be 18.88 kcal mol−1 which was aligned with the reported hydrolysable ester values. Consequently, the kinetic data analysis is crucial to predict the optimum analysis and storage conditions.

The microfabricated potentiometric electrodes have been used in the field of medicine and biological sciences in the last few decades due to their various in-vivo sensing applications in addition to the cost effectiveness and easy processing. The proposed microfabricated electrodes use a low cost copper (Cu) substrate material on sensitized printed circuit board (PCB) which is easily patterned and compatible with the microfabrication processing. In this study, we further introduce the chemically prepared poly(3octylthiophene) (POT) as an ion-to-electron transducer layer between the microfabricated Cu electrode and the ionophore-doped ion-selective membrane. The incorporation of POT reduced the potential drift from ∼7 mV h −1 for bare Cu electrodes to ∼1 mV h −1 for POT modified Cu electrodes because of its hydrophobic nature. In addition, the dynamic response time was obviously decreased from (11 ± 7 s) to (3 ± 2 s) due to the fast transduction. Furthermore, ionophore screening has been performed using calix[6]arene and calix [4]arene to enhance the membrane selectivity towards neostigmine (NEO) as a model drug analyte. The proposed sensors showed higher sensitivity, lower LOD when compared to the ionophore-free membrane. The incorporation of calix [4]arene ionophore improved the selectivity towards NEO in the presence of its potential impurities.

Nitroanilines are environmentally toxic pollutants which are released into aquatic systems due to uncontrolled industrialization. Therefore, it is crucial to convert these hazardous nitroanilines into a harmless or beneficial counterpart. In this context, we present the chemical reduction of 4-nitroaniline (4-NA) by NaBH 4 utilizing Prussian blue analogue (PBA) as nanocatalyst. PBAs can serve as inexpensive, eco-friendly, and easily fabricated nanocatalysts. PBA cobalt tetracyanonickelate hexacyanochromate (CoTCNi/HCCr) was stoichiometrically prepared by a facile chemical coprecipitation. Chemical, phase, composition, and molecular interactions were investigated by XRD, EDX, XPS, and Raman spectroscopy. Additionally, SEM and TEM micrographs were utilized to visualize the microstructure of the nanomaterial. The findings revealed the synthesized PBA of the cubic phase and their particles in nanosheets. The band gap was estimated from the optical absorption within the UV−vis region to be 3.70 and 4.05 eV. The catalytic performance of PBA for the reduction of 4-NA was monitored by UV−vis spectroscopy. The total reduction time of 4-NA by PBA was achieved within 270 s, and the computed rate constant (k) was 0.0103 s −1 . The synthesized PBA nanoparticles have the potential to be used as efficient nanocatalysts for the reduction of different hazardous nitroaromatics.

Background Hypertension is a key risk factor for ischemic heart disease and atherosclerosis. Most patients require a combination of antihypertensive medications to accomplish their therapeutic goals. Antihypertensive medicines such as calcium channel blockers and angiotensin receptor blockers are indicated for patients whose high blood pressure cannot be controlled with monotherapy. The combination of amlodipine besylate (AML) with irbesartan (IRB) is an example of this synergistic activity in lowering blood pressure. Objective In this regard, the goal of the research is to develop sensitive spectrophotometric methods for the simultaneous determination of amlodipine besylate and irbesartan. Methods Three simple ratio spectra-manipulating spectrophotometric methods namely, ratio difference, mean centering of ratio spectra, and derivative ratio, were developed for the simultaneous assay of the cited mixture. Results Linear correlations were attained over the concentration range of 1–35 μg/mL and 2–35 μg/mL for amlodipine besylate and irbesartan, respectively. The methods were validated according to the International Conference on Harmonization guidelines with good results. Conclusion The methods developed were successfully applied for the assay of the cited drugs in their marketed formulation. They could be efficiently used for routine analysis of the mentioned drugs in QC laboratories. Highlights The proposed approaches do not require expensive solvents or complex instruments. They could be used in routine laboratory tests where time and cost are crucial.

Five simple, sensitive, and eco-friendly LC and UV spectrophotometric methods have been developed for the simultaneous determination of phenylephrine hydrochloride (PHE) and prednisolone acetate (PRD) in their combined dosage form. The first method was reversed-phase (RP) LC using methanol-water-heptane-1-sulfonic acid sodium salt (75 + 25 + 0.1, v/v/w) as a mobile phase. Separation was achieved using an XSelect HSS reversed-phase C18 analytical column (250 × 4.6 mm, 5µm). The flow rate was 1.0 mL/min and UV detection was done at 230 nm. Quantification was achieved over the concentration ranges of 5-50 µg/mL for PHE and 2-90 µg/mL for PRD. Four spectrophotometric methods were proposed, namely dual wavelength, first derivative of ratio spectra, ratio difference, and mean-centering of ratio spectra. Linearity was observed in the concentration ranges of 10-120 and 5-35 µg/mL for PHE and PRD, respectively, for the spectrophotometric methods. Green solvents were used in the proposed methods because they play a vital role in the analytical methods' influence on the environment. The suggested methods were validated regarding linearity, accuracy, and precision according to the International Conference on Harmonization guidelines, with satisfactory results. These methods could be used as harmless substitutes for routine analysis of the mentioned drugs, with no interference from excipients.