Little-Cost Potentiometric and Spectrophotometric Procedures for Cephalothin Assessment in Pure and Biological Fluids

Low-cost potentiometric and spectrophotometric procedures for cephalothin (CPI) determination in pure and biological fluids were investigated. The potentiometric technique is created through titration of CPI with an aqueous medium of 0.1 M NaOH at an ionic strength of μ = 0.3 M sodium chloride and room temperature by a combined glass pH electrode. Using the standard addition method, we found that the detection and quantitative limits were 0.042 mg/mL, with the standard deviation SD = 0.011, correlation coefficient R = 0.9880 (n = 5), and linear concentration ranges from 0.042 to 0.82 mg/mL. This technique was utilized to assess CPI in pure solutions, urine, and serum with suitable results. No interference was exposed in the presence of public components of the samples under study. Recovery of CPI for pure and biological fluids is in the range of 98.2-101%. Also, the spectrophotometric method has been performed through the formation of the Prussian Blue (PB) complex. The reaction between the acidic hydrolysis product of CPI (T = 60 °C) and the mixture of Fe3+ with hexacyanoferrate (III) ions (HCF(III)) was detected for the spectrophotometric determination of the drug. The maximum absorbance of the formed complex was measured at λ = 283 nm with 2.0 × 103 L mol-1 cm-1 molar absorptivity. Reaction states have been advanced to acquire the PB complex of great sensitivity and longer stability. In optimal states, the absorbent of the PB compound was attained to grow linearly with the increase in the concentration of CPI, which agrees with the correlation coefficient values. The detection and quantitative limits were 0.000036 and 0.0012 mg/mL, respectively, with the standard deviation, SD = 0.0005, correlation coefficient, R = 0.9955 (n = 5), and the linearity range of the calibration plot 0.0005-0.02 mg/mL CPI. The planned technique was positively utilized for the detection of CPI in both urine and serum models. The results fit well with the data found from the potentiometric method.

Exploring the binding behavior mechanism of vitamin B12 to α-Casein and β-Casein: multi-spectroscopy and molecular dynamic approaches

The aim of this study was to investigate the behavior interaction of α-Casein-B12 and β-Casein-B12 complexes as binary systems through the methods of multiple spectroscopic, zeta potential, calorimetric, and molecular dynamics (MD) simulation. Fluorescence spectroscopy denoted the role ofB12as a quencher in both cases of α-Casein and β-Casein fluorescence intensities, which also verifies the existence of interactions. The quenching constants of α-Casein-B12 and β-Casein-B12 complexes at 298 K in the first set of binding sites were 2.89 × 104 and 4.41 × 104 M-1, while the constants of second set of binding sites were 8.56 × 104 and 1.58 × 105 M-1, respectively. The data of synchronized fluorescence spectroscopy at Δλ = 60 nm were indicative of the closer location of β-Casein-B12 complex to the Tyr residues. Additionally, the binding distance between B12 and the Trp residues of α-Casein and β-Casein were obtained in accordance to the Förster's theory of nonradioactive energy transfer to be 1.95 nm and 1.85 nm, respectively. Relatively, the RLS results demonstrated the production of larger particles in both systems, while the outcomes of zeta potential confirmed the formation of α-Casein-B12 and β-Casein-B12 complexes and approved the existence of electrostatic interactions. We also evaluated the thermodynamic parameters by considering the fluorescence data at three varying temperatures. According to the nonlinear Stern-Volmer plots of α-Casein and β-Casein in the presence of B12 in binary systems, the two sets of binding sites indicated the detection of two types of interaction behaviors. Time-resolved fluorescence results revealed that the fluorescence quenching of complexes are static mechanism. Furthermore, the outcomes of circular dichroism (CD) represented the occurrence of conformational changes in α-Casein and β-Casein upon their binding to B12 as the binary system. The experimental results that were obtained throughout the binding of α-Casein-B12 and β-Casein-B12 complexes were confirmed by molecular modeling.Communicated by Ramaswamy H. Sarma.

Cellulose nanocrystals derived from chicory plant: an un-competitive inhibitor of aromatase in breast cancer cells via PI3K/AKT/mTOP signalling pathway

A significant contributing factor in the development of breast cancer is the estrogens. The synthesis of estrogens is primarily facilitated by aromatase (CYP19), a cytochrome P450 enzyme. Notably, aromatase is expressed at a higher level in human breast cancer tissue compared with the normal breast tissue. Therefore, inhibiting aromatase activity is a potential strategy in hormone receptor-positive breast cancer treatment. In this study, Cellulose Nanocrystals (CNCs) were obtained from Chicory plant waste through a sulfuric acid hydrolysis method with the objective of investigating that whether the obtained CNCs could act as an inhibitor of aromatase enzyme, and prevent the conversion of androgens to estrogens. Structural analysis of CNCs was carried out using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), while morphological results were obtained using AFM, TEM, and FE-SEM. Furthermore, the nano-particles were found to be spherical in shape with a diameter range of 35-37 nm and displayed a reasonable negative surface charge. Stable transfection of MCF-7 cells with CYP19 has demonstrated the ability of CNCs to inhibit aromatase activities and prevent cell growth by interfering with the enzyme activities. Spectroscopic results revealed the binding constant of CYP19-CNCs and (CYP19-Androstenedione)-CNCs complexes to be 2.07 × 103 L/gr and 2.06 × 104 L/gr, respectively. Conductometry and CD data reported different interaction behaviors among CYP19 and CYP19-Androstenedione complexes at the presence of CNCs in the system. Moreover, the addition of CNCs to the solution in a successive manner resulted in the enhancement of the secondary structure of the CYP19-androstenedione complex. Additionally, CNCs showed a marked reduction in the viability of cancer cells compared to normal cells by enhancing the expression of Bax and p53 at protein and mRNA levels, and by decreasing mRNA levels of PI3K, AKT, and mTOP, as well as protein levels of PI3Kg-P110 and P-mTOP, in MCF-7 cells after incubation with CNCs at IC50 concentration. These findings confirm the decrease in proliferation of breast cancer cells associated with induction of apoptosis through down-regulation of the PI3K/AKT/mTOP signaling pathway. According to the provided data, the obtained CNCs are capable of inhibiting aromatase enzyme activity, which has significant implications for the treatment of cancer.Communicated by Ramaswamy H. Sarma.

Pretreatment and analysis techniques development of TKIs in biological samples for pharmacokinetic studies and therapeutic drug monitoring

Tyrosine kinase inhibitors (TKIs) have emerged as the first-line small molecule drugs in many cancer therapies, exerting their effects by impeding aberrant cell growth and proliferation through the modulation of tyrosine kinase-mediated signaling pathways. However, there exists a substantial inter-individual variability in the concentrations of certain TKIs and their metabolites, which may render patients with compromised immune function susceptible to diverse infections despite receiving theoretically efficacious anticancer treatments, alongside other potential side effects or adverse reactions. Therefore, an urgent need exists for an up-to-date review concerning the biological matrices relevant to bioanalysis and the sampling methods, clinical pharmacokinetics, and therapeutic drug monitoring of different TKIs. This paper provides a comprehensive overview of the advancements in pretreatment methods, such as protein precipitation (PPT), liquid-liquid extraction (LLE), solid-phase extraction (SPE), micro-SPE (μ-SPE), magnetic SPE (MSPE), and vortex-assisted dispersive SPE (VA-DSPE) achieved since 2017. It also highlights the latest analysis techniques such as newly developed high performance liquid chromatography (HPLC) and high-resolution mass spectrometry (HRMS) methods, capillary electrophoresis (CE), gas chromatography (GC), supercritical fluid chromatography (SFC) procedures, surface plasmon resonance (SPR) assays as well as novel nanoprobes-based biosensing techniques. In addition, a comparison is made between the advantages and disadvantages of different approaches while presenting critical challenges and prospects in pharmacokinetic studies and therapeutic drug monitoring.

Spectroscopy and molecular simulation on the interaction of Nano-Kaempferol prepared by oil-in-water with two carrier proteins: An investigation of protein-protein interaction

In this work, the interaction of human serum albumin (HSA) and human holo-transferrin (HTF) with the prepared Nano-Kaempferol (Nano-KMP) through oil-in-water procedure was investigated in the form of binary and ternary systems by the utilization of different spectroscopy techniques along with molecular simulation and cancer cell experiments. According to fluorescence spectroscopy outcomes, Nano-KMP is capable of quenching both proteins as binary systems by a static mechanism, while in the form of (HSA-HTF) Nano-KMP as the ternary system, an unlinear Stern-Volmer plot was elucidated with the occurrence of both dynamic and static fluorescence quenching mechanisms in the binding interaction. In addition, the two acquired Ksv values in the ternary system signified the existence of two sets of binding sites with two different interaction behaviors. The binding constant values of HSA-Nano KMP, HTF-Nano-KMP, and (HSA-HTF) Nano-KMP complexes formation were (2.54 ± 0.03) × 104, (2.15 ± 0.02) × 104 and (1.43 ± 0.04) × 104M-1at the first set of binding sites and (4.68 ± 0.05) × 104 M-1 at the second set of binding sites, respectively. The data of thermodynamic parameters confirmed the major roles of hydrogen binding and van der Waals forces in the formation of HSA-Nano KMP and HTF-Nano KMP complexes. The thermodynamic parameter values of (HSA-HTF) Nano KMP revealed the dominance of hydrogen binding and van der Waals forces in the first set of binding sites and hydrophobic forces for the second set of binding sites. Resonance light scattering (RLS) analysis displayed the existence of a different interaction behavior for HSA-HTF complex in the presence of Nano-KMP as the ternary system. Moreover, circular dichroism (CD) technique affirmed the conformational changes of the secondary structure of proteins as binary and ternary systems. Molecular docking and molecular dynamics simulations (for 100 ns) were performed to investigate the mechanism of KMP binding to HSA, HTF, and HSA-HTF. Next to observing a concentration and time-dependent cytotoxicity, the down regulation of PI3K/AkT/mTOR pathway resulted in cell cycle arrest in SW480 cells.

Developing Metal Complexes for Captopril Quantification in Tablets Using Potentiometric and Conductometric Methods

Potentiometric and conductometric methods were successfully applied to elucidate the interaction of 10 ions, viz., Cr³⁺, Fe³⁺, La²⁺, Th⁴⁺, Co²⁺, Mn²⁺, Pd²⁺, Sr²⁺, Ti²⁺, and Zr²⁺, with the antihypertensive drug captopril (CAP) and its role to determine CAP in pure powder and tablet forms. The ionization constant of CAP and the generated complexes' stability constants (log K) were evaluated using potentiometric and conductometric methods at 25 ± 0.1 °C and 0.05 M ionic strength (I) of NaNO₃ aqueous solution, and CAP was then determined in pure powder and tablet forms. Complexes having metal:ligand ratios of 1:1, 1:2, and/or 1:3 were produced, regardless of the type of the ligand or metal ions. Both the suggested potentiometric and conductometric procedures were utilized to confirm the stoichiometry of the M-CAP binary complexes formed. These two different techniques were utilized successfully to determine CAP in pure powder and tablet forms. Using the standard addition method (SAM) based on the Gran plot, CAP was satisfactorily determined throughout the concentration range of 0.83-13.04 mg/mL (SD = 0.20, R = 0.9986 (n = 5)), with a detection limit of 0.64 mg/mL (SD = 0.20, R = 0.9986 (n = 5)). In the presence of common tablet excipients, no interferences were observed. The percentage of CAP recovered from various dosage formulations (tablets) varied from 95.88 to 99.92%.

A novel vision into the binding behavior of curcumin with human serum albumin-holo transferrin complex: molecular dynamic simulation and multi-spectroscopic perspectives

In this work, we investigated the simultaneous binding of curcumin (CUR) to human serum albumin (HSA) and human-holo transferrin (HTF) in the roles of binary and ternary systems. The binding affinity and binding site of protein-protein interaction were studied by the methods of multiple spectroscopic and molecular dynamics (MD) simulation. According to the results, the measurements for binding constant of HSA-CUR, HTF-CUR and (HSA-HTF) CUR complexes were observed to be 1.51 × 10⁵, 7.93 × 10⁴ and 1.44 × 10⁵ M^-1 respectively. Thermodynamic parameters were considered to be set at three varying temperatures including 298, 303, and 308 K. In conformity to the negative values of ΔH⁰ and ΔS⁰ the significant roles of hydrogen binding and van der-Waals forces in the formation of complexes are quiet evident. The binding distance between Trp residues of HSA, HTF and HSA-HTF upon interaction with CUR, were acquired by applying the Förster's theory of non-radioactive energy transfer and reported to be 2.04 nm, 1.78 nm, and 1.86 nm, respectively. In accordance with the conductometry and Resonance light scattering (RLS) results, there were different interaction behaviors among the HSA-HTF complex and CUR in ternary system when being compared to the outcomes of binary system. The secondary structure of all three cases increased as the CUR concentration was intensified, which confirmed the inducement of proteins conformational changes through the application of circular dichroism (CD) technique. The experimental results that were acquired throughout the binding of HSA-CUR, HTF-CUR, and (HSA-HTF) CUR complexes were approved by molecular modeling.Communicated by Ramaswamy H. Sarma.

Simple and efficient spectroscopic-based univariate sequential methods for simultaneous quantitative analysis of vandetanib, dasatinib, and sorafenib in pharmaceutical preparations and biological fluids

Six sequential spectrophotometric-based univariate methods were developed and validated for the simultaneous estimation of three novel anticancer drugs vandetanib (VAN), dasatinib (DAS), and sorafenib (SOR) in a mixture, without the requirement for separation. These methods are novel, simple, precise, and accurate. Different steps including zero crossing, ratio-based, and/or derivative spectra were utilized to develop these analytical methods, namely, ratio difference spectrophotometric method, constant center method, successive derivative ratio method, isoabsorptive method, mean centering of the ratio spectra method, and derivative ratio spectrum-zero crossing method. The calibration curve linearity was ranged from 2 to 9, 2-9, and 3-9 μgmL^-1 for VAN, DAS, and SOR, respectively. These established methods were applied for the quantification of the three selected drugs in different biological fluids (spiked human plasma and urine) and pharmaceutical preparations. The aforementioned methods were established for the concurrent estimation of ternary and binary mixtures to enhance the signal-to-noise ratio. The results did not statistically differ from the other reported methods, indicating no significant difference in accuracy and precision at p = 0.05.