(−)-6-epi-Artemisinin, a Natural Stereoisomer of (+)-Artemisinin in the Opposite Enantiomeric Series, from the Endemic Madagascar Plant Saldinia proboscidea, an Atypical Source

Chemical and biological investigation of the Madagascar endemic plant Saldinia proboscidea led to the isolation of an isomer of artemisinin, (−)-6-epi-artemisinin (2). Its structure was elucidated using a combination of NMR and mass spectrometry. The absolute configuration was established by chemical syntheses of compound 2 as well as a new stereoisomer (3). The comparable bioactivities of artemisinin (1) and its isomer (−)-6-epi-artemisinin (2) revealed that this change in configuration was not critical to their biological properties. Bioactivity was assessed using an apoptosis induction assay, a SARS-CoV-2 inhibitor assay, and a haematin polymerization inhibitory activity (HPIA) assay. This is the first report of an artemisinin-related compound from a genus not belonging to Artemisia and it is the first isolation of an artemisinin-related natural product that is the opposite enantiomeric series relative to artemisinin from Artemisia annua.

STATISTICALLY OPTIMIZED AND BOX-BEHNKEN DESIGN ASSISTED METHOD DEVELOPMENT AND VALIDATION OF AN ANTIPSYCHOTIC MEDICATION OLANZAPINE AND ITS RELATED IMPURITIES BY REVERSE-PHASE HPLC-UV SPECTROSCOPY

Objective: Statistically designed and Box-Behnken design (BBD) assisted reversed-phase high-performance liquid chromatography-ultraviolet (HPLC-UV) method was developed and validated for the identification of an antipsychotic medication Olanzapine and its organic impurities in pure drug along with forced degradation studies. Methods: The present developed method employed BBD optimized chromatographic conditions comprising of an Inertsil ODS 3V analytical column with dimension 250 mm x 4.6 mm and particle size 5µ. The isocratic mobile phase was used as a mixture of monobasic sodium phosphate buffer (0.01 M, pH 6), methanol and acetonitrile in the proportion of 40/30/30, v/v. The mobile phase flow rate and UV λmax was 1 ml/min and 260 nm, respectively. The method was optimized by Box-Behnken design using design expert software, comprising of three factors for Olanzapine for instance flow rate (A), mobile phase composition (B) and pH (C) while resolution between Olanzapine related compound A and Olanzapine related compound B (Y1) and tailing of Olanzapine (Y2) were taken as a response. Results: Application of BBD yielded statistically designed method with excellent quality parameters achieved in terms of linearity with the coefficient of correlation (R2>0.9999), limit of detection (LOD, 0.0023-0.16 µg/ml), the limit of quantification (LOQ, 0.007-0.39 µg/ml), accuracy (99-100%) and precision ((2%, relative standard deviation (%RSD) were evaluated as per latest available procedures. Conclusion: Forced degradation conditions were carried out, demonstrated that the optimized method was stable and no any interfering peaks eluting at the similar retention time of the studied compounds. The method was found to be stable, easy, rugged and robust, could be applied for the similar types of the pure drug.

Tetralone Derivatives From a Deep-Sea-Derived Fungus Cladosporium Sp. HDN17-58

One new tetralone derivative, named aladothalen (1), and one known biogenetically related compound, (3 S,4 S)−3,4,8-trihydroxy-3,4-dihydronaphthalen-1(2 hours)-one (2), were isolated from a deep-sea-derived-fungal Cladosporium sp. HDN17-58. Their structures, including absolute configurations, were elucidated by extensive NMR, MS, and ECD analyses. Compound 1 exhibited potent bacteriostatic activity against Bacillus cereus, Mycobacterium phlei and methicillin-resistant coagulase-negative Staphylococci, with a MIC value of 25 µM.

Slow Relaxation of the Magnetization in Anilato-Based Dy(III) 2D Lattices

The search for two- and three-dimensional materials with slow relaxation of the magnetization (single-ion magnets, SIM and single-molecule magnets, SMM) has become a very active area in recent years. Here we show how it is possible to prepare two-dimensional SIMs by combining Dy(III) with two different anilato-type ligands (dianions of the 3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone: C6O4X22−, with X = H and Cl) in dimethyl sulfoxide (dmso). The two compounds prepared, formulated as: [Dy2(C6O4H2)3(dmso)2(H2O)2]·2dmso·18H2O (1) and [Dy2(C6O4Cl2)3(dmso)4]·2dmso·2H2O (2) show distorted hexagonal honeycomb layers with the solvent molecules (dmso and H2O) located in the interlayer space and in the hexagonal channels that run perpendicular to the layers. The magnetic measurements of compounds 1, 2 and [Dy2(C6O4(CN)Cl)3(dmso)6] (3), a recently reported related compound, show that the three compounds present slow relaxation of the magnetization. In compound 1 the SIM behaviour does not need the application of a DC field whereas 2 and 3 are field-induced SIM (FI-SIM) since they show slow relaxation of the magnetization when a DC field is applied. We discuss the differences observed in the crystal structures and magnetic properties based on the X group of the anilato ligands (H, Cl and Cl/CN) in 1–3 and in the recently reported derivative [Dy2(C6O4Br2)3(dmso)4]·2dmso·2H2O (4) with X = Br, that is also a FI-SIM.

Response Surface Method Aided Development and Validation of Stability Indicating RP-HPLC-UV Method for Impurities of Dextromethorphan Hydrobromide in API and Three Marketed Formulations

An innovative, specific, economical and precise method was developed and validated by employing reverse phase high performance liquid chromatography (HPLC) for contemporaneous estimation of dextromethorphan hydrobromide (DHB) along with its impurities in liquid formulation with forced degradation studies and confirmation of content of DHB in composition label in three market formulations along with their impurities were detected by this method. The optimized chromatographic conditions comprised of column (25 cm × 0.46 cm) × 5 μm Kromasil C8 bearing flow rate of 1.5 mL/min and wavelength 220 nm for UV-estimation. Design of experiments were implemented by following Box Behnken design with most optimum parameters selected as follows, column temperature (A), flow rate (B) and pH (C) with corresponding responses comprised of resolution between related compound A (RCA) and DHB (Y1), tailing of DHB (Y2) and resolution between related compound B (RCB) and DHB (Y3). Stress testing was performed and proved that method was stable as no interfering peaks were observed. All validation parameters including suitability, linearity, accuracy, specificity, limit of detection, limit of quantitation, ruggedness, robustness and stress study were evaluated as per updated ICH guidelines and found to be within limit for pure DHB and detected impurities.

Asymmetric Synthesis of Isoxazol-5-ones and Isoxazolidin-5-ones

Isoxazol-5-ones and isoxazolidin-5-ones represent two important classes of heterocycles, with several applications as bioactive compounds and as versatile building blocks for further transformations. Unlike the parent aromatic isoxazoles, the presence of one or two stereocenters in the ring renders their asymmetric construction particularly important. In this review, starting from the description of general features and differences between these two related compound families, we present an overview on the most important enantioselective synthesis strategies to access these heterocycles. Both chiral metal catalysts and organocatalysts have recently been successfully employed for this task and some of the most promising approaches will be discussed.1 Introduction2 Isoxazol-5-ones as Nucleophiles2.1 Isoxazol-5-ones as C-Nucleophiles2.2 Isoxazol-5-ones as N-Nucleophiles2.3 Isoxazol-5-ones as C-Nucleophiles in Cyclization Processes3 Asymmetric Construction of Isoxazolidin-5-ones3.1 Enantioselective α-Functionalizations of Isoxazolidin-5-ones4 Arylideneisoxazol-5-ones in Conjugated Addition5 Conclusions

Method Development and Validation of Famotidine Oral Suspension by RP-HPLC Method

For perseverance of a simple, fast and selective procedure were developed in drug substance and its pharmaceutical preparations. the proposed project, a successful attempt has been made to develop a simple, accurate, economic and rapid method for the estimation and to validate the method. As a result, a simple, economical, precise and accurate method was developed and validated by Reverse Phase High Performance Liquid Chromatography (RP-HPLC). The main objective for that is to improve the conditions and parameters, which should be followed in the development and validation. developed Reverse phase HPLC technique was done utilizing filtered and degassed pH-6.0 Acetate buffer as a Mobile phase-A and pH-6.0 Acetate buffer and organic mixture in the ratio of 30:70 as a Mobile phase-B. By using waters X-Bridge C18 (150*4.6mm), 3.5µm column separation was achieved. The flow rate and run time was 0.8mL/min and 45minutes. The detection wavelength was 265nm.The average percentage recovery for related compound-C was found to be 94.3%, 95.9%, 96.0% represents the accuracy of the method and for related compound-D was found to be 95.8, 95.4 and 96.4. The %RSD for related compound-C was found to be 5.576 and for related compound-D was found to be 1.588 represents the precision of the method. The correlation coefficient square for , related compound-C and related compound-D was found to be 0.999999, 0.9992 and 0.9991 respectively. Respective parameters met the acceptance criteria, from the results concluded that the developed method was precise and accurate.

Prediction of an MMP-1 inhibitor activity cliff using the SAR matrix approach and its experimental validation

A matrix metalloproteinase 1 (MMP-1) inhibitor activity cliff was predicted using the SAR Matrix method. Compound 4 was predicted as a highly potent activity cliff partner and found to possess 60 times higher inhibitory activity against MMP-1 than the structurally related compound 3. Furthermore, pharmacophore fitting of synthesized compounds indicated that the correctly predicted activity cliff was caused by interactions between the trifluoromethyl group at para position in compound 4 and residue ARG214 of MMP-1.