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Inorganic lead-halide perovskite, cesium lead bromide (CsPbBr3), shows outstanding optoelectronic properties. Both solution- and melt-based methods have been proposed for CsPbBr3 crystal growth. The solution-based growth was done at low-temperature, whereas the melt-based growth was done at high-temperature. However, the comparison of optical, physical, and defect states using these two different growth conditions has been scarcely studied. Here, we have compared the thermal and optical properties of solution-grown and melt-grown single crystals of CsPbBr3. Positron Annihilation Lifetime Spectroscopy (PALS) analysis showed that melt-grown crystal has a relatively smaller number of defects than the chemical synthesis method. In addition, crystals grown using the chemical method showed a higher fluorescence lifetime than melt-grown CsPbBr3.

A simple and robust high‐performance liquid chromatography (HPLC) method was developed for organic impurities of hydroxyzine hydrochloride in pharmaceuticals. The developed method was designed to estimate all organic impurities of hydroxyzine. The HPLC separation was achieved using C18 column (150 × 3.9 mm, 5 μm) along with a binary gradient consisting of mobile phases A (0.1%, trifluoroacetic acid in purified water) and B (0.05%, trifluoroacetic acid in acetonitrile), a flow rate of 0.7–mL/min, a column temperature of 30°C and a sample temperature of 25°C. The detection wavelength used was 230 nm for the estimation of impurity‐A, impurity‐B, and all unspecified impurities and degradation products, whereas impurity‐C was quantitated using 254 nm. The stability‐indicating property of the developed HPLC technique was assessed using stress testing conditions of hydrolysis, oxidation, thermal, photo‐light, and humidity. The validation study was performed for the limit of detection and limit of quantification, linearity, and recoveries were 0.03%, 0.05%, and 0.1132–2.9920 μg/mL (R2 > 0.999), and 84.09%–109.74%, respectively. The proposed method is highly suitable for the determination of assay, organic impurities, and degradation products of the hydroxyzine. The chemical structure of degradation product 1 (hydroxyzine N‐Oxide) and degradation product 2 (O‐Acetyl hydroxyzine) were identified with the supporting data of LC‐mass spectrometry (LC‐MS) and high‐resolution MS. [ABSTRACT FROM AUTHOR]

The R,S‐enantiomer impurity and diastereomer impurities (S,S‐isomer and R,R‐isomer) of the solifenacin (S,R‐enantiomer) were effectively separated and quantified simultaneously utilizing normal‐phase high‐performance liquid chromatography with a chiral stationary phase consisting of amylose tris (3,5‐dimethylphenylcarbamate) coated on silica‐gel (Chiralpak, AD‐H). The enantiomeric and stereo‐selective separation was achieved within a run time of 35 minutes using a mobile phase of 'n‐hexane, ethanol, and diethylamine' in an isocratic elution mode with a detection wavelength of 220 nm. The validation attributes assessed were accuracy (which showed excellent recoveries between 97.5% and 100.4%) and linearity (which was proven in the range of 0.081–1.275 μg.mL−1, with a linear regression of 0.999). The stress testing experiments proved that the developed methodology by the HPLC technique has stability‐indicating characteristics, as all closely eluting peak pairs were separated well with a resolution of 2.3 and without any interference. The proposed methodology was highly efficient in separating and simultaneously determining the chiral impurities (enantiomers and diastereomers) of the solifenacin in the release and stability sample analyses of drug substances and tablets in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Propranolol hydrochloride (PPH) is a medication of beta‐adrenergic receptors. It is used to treat pediatric hemangiomas that are growing and need systemic therapy. A reversed‐phase high‐performance liquid chromatography (HPLC) was made to separate and estimate the amounts of ten known organic impurities of propranolol in bulk drugs, tablets, and capsule dosage forms. The chromatographic separation was achieved on a C18 column (100 × 4.6 mm, 2.7 μm) using a binary gradient mixture of pH 2.3 phosphate buffer and organic modifiers of acetonitrile, methanol, and isopropyl alcohol as the mobile phase. The stability‐indicating character of the proposed method was proven using stress testing study. The test method was validated for specificity, limit of detection, limit of quantitation, linearity, precision, accuracy, and robustness. For the propranolol and its ten organic impurities, the limit of quantitation, linearity, and recoveries were found in a range of 0.0123–0.4266 μg/mL (R2 > 0.9982) and 89.2–98.9%, respectively. The proposed liquid chromatography method is found to be highly suitable for impurity profiling of propranolol in bulk drugs and pharmaceutical formulations (tablets and capsules). [ABSTRACT FROM AUTHOR]

The present research developed and validated a new stability‐indicating technique for the stereo‐selectively enantiomers of the antiviral nucleoside analog Valacyclovir hydrochloride (VAL). The chiral separation was performed using normal‐phase high‐performance liquid chromatography (HPLC) with a chiral stationary phase consisting of amylose tris(3‐chloro‐5‐methylphenylcarbamate) and a mobile phase of "n‐hexane, methanol, ethanol, and diethylamine", flow rate of 0.60 mL/min, column temperature of 30°C, injection volume of 10‐μL, detection wavelength of 254‐nm, and run time of 25‐min. The enantiomers (S‐enantiomer, L‐isomer, R‐enantiomer, and D‐isomer) of Valacyclovir were separated with a resolution of 4.8 and no interference. The validation parameters verified for the proposed method, linearity in a range of 0.1002–24.3486 μg/mL (0.02–4.86%) with a regression coefficient of 0.999, and the accuracy was determined with excellent recoveries ranging from 94.38%–109.97%. The concentrations established for the detection limit and quantitation limit were 0.01% and 0.02%, respectively. The forced degradation experiments were used to assess the stability‐indicating qualities. D‐Valacyclovir impurity was successfully evaluated in release and stability samples of VAL in drug substance and tablet dosage forms using the proposed normal phase chiral HPLC approach. [ABSTRACT FROM AUTHOR]

Abstract Expansion of the glutamine tract (poly-Q) in the protein huntingtin (HTT) causes the neurodegenerative disorder Huntington’s disease (HD). Emerging evidence suggests that mutant HTT (mHTT) disrupts brain development. To gain mechanistic insights into the neurodevelopmental impact of human mHTT, we engineered male induced pluripotent stem cells to introduce a biallelic or monoallelic mutant 70Q expansion or to remove the poly-Q tract of HTT. The introduction of a 70Q mutation caused aberrant development of cerebral organoids with loss of neural progenitor organization. The early neurodevelopmental signature of mHTT highlighted the dysregulation of the protein coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2), a transcription factor involved in mitochondrial integrated stress response. CHCHD2 repression was associated with abnormal mitochondrial morpho-dynamics that was reverted upon overexpression of CHCHD2. Removing the poly-Q tract from HTT normalized CHCHD2 levels and corrected key mitochondrial defects. Hence, mHTT-mediated disruption of human neurodevelopment is paralleled by aberrant neurometabolic programming mediated by dysregulation of CHCHD2, which could then serve as an early interventional target for HD.

Inorganic lead-halide perovskite, cesium lead bromide (CsPbBr3), shows outstanding optoelectronic properties. Both solution- and melt-based methods have been proposed for CsPbBr3 crystal growth. The solution-based growth was done at low-temperature, whereas the melt-based growth was done at high-temperature. However, the comparison of optical, physical, and defect states using these two different growth conditions has been scarcely studied. Here, we have compared the thermal and optical properties of solution-grown and melt-grown single crystals of CsPbBr3. Positron Annihilation Lifetime Spectroscopy (PALS) analysis showed that melt-grown crystal has a relatively smaller number of defects than the chemical synthesis method. In addition, crystals grown using the chemical method showed a higher fluorescence lifetime than melt-grown CsPbBr3. [ABSTRACT FROM AUTHOR]