Ionic Liquids Can Permanently Modify Porous Silicon Surface Chemistry

To develop ionic liquid/porous silicon (IL/pSi) microarrays we have contact pin‐printed 20 hydrophobic and hydrophilic ionic liquids onto as‐prepared, hydrogen‐passivated porous silicon (ap‐pSi) and then determined the individual IL spot size, shape and associated pSi surface chemistry. The results reveal that the hydrophobic ionic liquids oxidize the ap‐pSi slightly. In contrast, the hydrophilic ionic liquids lead to heavily oxidized pSi (i.e., ox‐pSi). The strong oxidation arises from residual water within the hydrophilic ILs that is delivered from these ILs into the ap‐pSi matrix causing oxidation. This phenomenon is less of an issue in the hydrophobic ILs because their water solubility is substantially lower.     

An assessment of the impact of green tea extract on palbociclib pharmacokinetics using a validated UHPLC–QTOF–MS method

Green tea extracts (GTE) has been reported to be a kinase inhibitor and modulator for various drug metabolizing enzymes. It may give synergetic antioncogenic effect, but with a possibility of pharmacokinetic interactions with various co‐administered anticancer agents like palbociclib (PAL), a selective inhibitor of CDK‐4/6 primarily metabolized by CYP3A enzyme. To explore the impact of GTE on PAL pharmacokinetics in Sprague–Dawley rats, a rapid and sensitive UHPLC–QTOF–MS method was established. Chromatographic separation was carried out on an Acquity UPLC BEH C₁₈ (100 × 2.1 mm, 1.7 μm) column using a gradient mobile phase system consisting of 0.1% formic acid and acetonitrile. Sample preparation was based on a simple protein precipitation method. Estimation of target ions [M + H]⁺ at m/z 448.2455 for PAL and m/z 441.2044 for ibrutinib (IS) was performed in selective ion mode ESI–HRMS. Good sensitivity (1.0 ng/mL) and linearity over a wide concentration range of 1–2000 ng/mL was exhibited by the method. The results indicated that the administration of GTE resulted in decreased oral bioavailability of PAL in both short‐ and long‐term conditions. However, when both conditions were compared, the variation was less for the peak concentration and area under the concentration–time curve level of PAL.     

Multidisciplinary Role of Mesoporous Silica Nanoparticles in Brain Regeneration and Cancers: From Crossing the Blood–Brain Barrier to Treatment

Mesoporous silica nanoparticles (MSNs) have gained wide attention for their role in biomedicine and as drug delivery vehicles. Their structural tunability, high surface area, and easy functionalization impart significant advantages over conventional materials. In this Review, recent advances in the synthesis, drug delivery, and therapeutic roles of MSNs in the treatment of various neurodegenerative and neuroinflammatory diseases are presented. The intention is to understand how MSN formulations that are capable of encapsulating drug molecules can enhance drug delivery by overcoming the blood–brain barrier (BBB) mediated by specific transport processes. The composition and characteristics of the BBB, and how alterations are observed in neurodegenerative diseases including Alzheimer's, epilepsy, and intracerebral hemorrhage are reviewed. Finally, the factors affecting efficient delivery of MSNs into the brain are summarized, and their most promising functional outcomes are discussed.     

Endocrine disruption: molecular interactions of chlorpyrifos and its degradation products with estrogen receptor

Structural Chemistry - Chlorpyrifos is an extensively used organophosphate pesticide showing broad-spectrum effectiveness on various target pests. Long-term sublethal exposure to this pesticide is...     

Greener approach for process intensification of iron haematinics by membrane nanofiltration

Iron haematinics are high-volume, low-cost drug products used to treat anaemia. For the preparation of iron haematinics, the manufacturers depend heavily on multipurpose-batch or semi-batch reactors. Here, process intensification of haematinics was carried out using membrane nanofiltration as a major operation. A total of three haematinics namely, iron (III) hydroxide polymaltose, iron gluconate, and iron sucrose complex were prepared, and the process intensified on dead-end filtration set up by using a polymeric membrane. Iron (III) hydroxide polymaltose experimental results were compared with commercially available standard. The membrane performance was characterized by various parameters such as flux, permeability, flux decline ratio, flux recovery ratio, percentage retention, fouling, etc., at different transmembrane pressures. The membrane surface was analysed by Scanning Electron Microscopy (SEM) to understand its morphology and fouling. The iron concentration was detected in the permeate stream using inductively coupled plasma optical emission (ICP-OES) spectroscopy to detect %retention (>99.99%) under all experimental conditions tested. The study led to optimized conditions for haematinics concentration by a membrane at a 10-bar trans-membrane pressure, which was applied for the preparation of iron gluconate salt. Overall, the study resulted in a green process with increased productivity.     

Application of ionic-liquid supported cloud point extraction for the determination of microcystin-leucine-arginine in natural waters

A cloud point extraction method has been developed using an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, BMiM PF(6)) for the determination of a widely studied cyanotoxin (microcystin leucine-arginine, MCLR) in natural waters. Extraction parameters such as sample pH, extraction temperature, extraction time, the amount of ionic liquid and the amount of extraction volume were investigated and optimized to achieve the maximum extraction efficiency. The results obtained indicated a good linearity with the correlation coefficient of 0.995 over the range of 0.5-50 μg L(-1). The relative standard deviation (RSD) of the method was 7.5% (n=6). The calculated method detection limit was 0.03 μg L(-1) (n=6). The practical applicability of the technique was demonstrated by analyzing water samples (n=9) collected from three different sites in local reservoirs.     

Unusual solvatochromism within 1-butyl-3-methylimidazolium hexafluorophosphate + poly(ethylene glycol) mixtures

Hybrid "green" solvent systems composed of room-temperature ionic liquids (ILs) and poly(ethylene glycols) (PEGs) may have enormous future potential. Solvatochromic absorbance probe behavior is used to assess the physicochemical properties of the mixture composed of IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) and PEG (average molecular weights of 200, 400, 600, and 1500) at ambient conditions. Lowest energy intramolecular charge-transfer absorbance maxima of a betaine dye, i.e., E(T)(N), indicates the dipolarity/polarizability and/or hydrogen-bond donating (HBD) acidity of the [bmim][PF 6] + PEG mixtures to be even higher than that of neat [bmim][PF(6)], the solution component with higher dipolarity/polarizability and/or HBD acidity. Dipolarity/polarizability (pi*) obtained separately from the electronic absorbance response of probe N, N-diethyl-4-nitroaniline shows a trend similar to E(T)(N ) thus confirming the unusually high dipolarity/polarizability of the [bmim][PF(6)] + PEG mixtures. Similar to E(T)(N ) and pi*, the HBD acidity (alpha) of [bmim][PF(6)] + PEG mixtures is also observed to be anomalously high. Contrary to what is observed for E(T)(N ), pi*, and alpha, the hydrogen-bond accepting (HBA) basicity (beta) of the [bmim][PF(6)] + PEG mixtures is observed to be lower than that predicted from ideal additive behavior indicating diminished HBA basicity of the mixture as compared to its neat components. A four-parameter simplified combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation is shown to satisfactorily predict the solvatochromic parameters within [bmim][PF(6)] + PEG mixtures. It is demonstrated that [bmim][PF(6)] + PEG mixtures possess physicochemical properties that are superior to those of either the neat IL or the neat PEG.     

Existence and regularity of solutions to nonlocal retarded differential equations

In this paper the existence and uniqueness of different types of solutions to a class of semilinear retarded differential equations with nonlocal history conditions are obtained by a fixed point argument. Also finite dimensional approximation of these solutions in a Hilbert space is established.