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BN/CC isosterism is an effective strategy to build hybrid functional molecules with unique properties. In contrast to the alkynyl iminium salts derived from cyclic (alkyl)(amino)carbenes (CAACs) that feature only one reversible reduction wave, the isoelectronic cationic CAAC-iminoboryl adducts could be singly and doubly reduced smoothly. Both the resultant neutral radical and anionic azaborataallenes bear NBC-mixed allenic structures. The former radical has a high spin-density of 0.55eat CCAACcarbon, yet exhibits formal boron-centered radical reactivity. The latter azaborataallenes feature the nucleophilic CCAACcenter and polar N(δ–)═B(δ+)═C(δ–) unit, and readily undergo nucleophilic substitution, isocyanide insertion, dipolar addition and cycloaddition reactions etc. The N-substituents have been shown to have a significant influence on the solid-state structure, thermal stability, and reactivity of azaborataallenes. This work showcases the allenic BN-unsaturated species as versatile building blocks in organic synthesis.

Azithromycin eye drops with a bioadhesive ocular drug‐delivery system can offer a simplified dosing regimen. In this study, we compared the pharmacokinetic properties and assessed the bioequivalence of a newly developed generic azithromycin eye drop with a branded formulation. This open‐label, single‐dose, randomized, crossover, sparse‐sampling ocular bioequivalence study was conducted on 48 healthy Chinese volunteers. Tear samples were collected for up to 36 hours, and each participant was randomly allocated to one of the prespecified sampling times. Tear drug concentrations were determined using a validated liquid chromatography‐tandem mass spectrometry method. The pharmacokinetic parameters were calculated via noncompartmental analysis. A nonparametric bootstrap method was used to obtain 90% confidence intervals (CIs) for the ratios of the test and reference drugs. Tolerability was evaluated for adverse events (AEs). After bootstrapping (1000 iterations), the 90%CIs for the log‐transformed ratios of Cmax, AUC0‐t, and AUC0–∞were within the acceptable bioequivalence range (80%–125%). No moderate‐to‐severe AEs were reported for either formulation. Bioequivalence was demonstrated between the two formulations. The sparse‐sampling design with the bootstrapping technique is promising for bioequivalence studies of topical ophthalmic drugs.

Linezolid, an oxazolidinone antibacterial agent with several formulations, has been widely used for over 20 years. This study aimed to compare the bioequivalence, pharmacokinetics, and safety of test and reference linezolid tablets after a single oral dose under fasting/fed conditions. In this open‐label, randomized, two‐period, crossover, bioequivalence study, 48 healthy volunteers were enrolled equally to fasting or fed groups to receive one 600‐mg test or reference linezolid tablet in each period. Pharmacokinetic parameters were calculated using noncompartmental methods. Adverse events (AEs) were recorded to assess safety. The geometric mean terminal half‐lives of test and reference formulations were 3.8 and 3.6 hours, respectively, under both fasting and fed conditions. The median time to reach the maximum observed concentration was 1.0 hour (both formulations) in the fasting group, and 2.0 hours (test formulation) and 2.5 hours (reference formulation) in the fed group. No substantial differences were observed in the area under plasma concentration–time curve (AUC) from time 0 to the last sampling time (AUC0‐t) and the maximum observed concentration (Cmax) between formulations. Geometric least square mean ratios for Cmax, AUC0‐t, and AUC from time 0 to infinity were approximately 100%, and the corresponding 90% confidence intervals for bioequivalence were within 80%–125%. Ten participants reported 11 AEs; AEs were mild, except for one pregnancy event with an outcome of induced absorption. Bioequivalence between the two linezolid formulations was demonstrated under fasting and fed conditions, and a similar safety profile was observed among healthy Chinese volunteers.

Misoprostol is a synthetic prostaglandin E1 derivative that has been used to treat duodenal and gastric ulcers, and to prevent ulcers caused by nonsteroidal anti‐inflammatory drugs in many countries. Misoprostol can also be used for medical abortion. This study aimed to investigate the pharmacokinetic profiles of misoprostol tablets (test product) by comparing them with Cytotec (200 μg) (reference product). To assess the bioequivalence between test and reference products, a two‐sequence, two‐period crossover study was conducted with 48 healthy Chinese subjects enrolled under fasting conditions. A validated liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) assay was used to determine the concentration of misoprostol acid in plasma. A mixed model analysis of variance was used to calculate the bioequivalence of pharmacokinetic (PK) parameters. The point estimate of geometric mean ratios with 90% confidence intervals for the maximum observed concentration (Cmax) and the area under the concentration‐time curve (AUC0‐t) for misoprostol acid in reference and test products were 107.8% and 106.5%, respectively (range 80%–125%). Additionally, none of the secondary PK parameters presented significant differences. No severe or more than moderate adverse events were detected in the 48 subjects. However, one subject discontinued the treatment due to drug‐related gastrointestinal reactions. All adverse events were mild with rates of 19.2% and 22.9% after the administration test and reference products, respectively. Overall, the bioequivalence between the two misoprostol products was demonstrated in fasting conditions, and all subjects tolerated both treatments.

Anionic oxoboranes and neutral iminoboranes, which are isoelectronic to ketones and alkynes, respectively, have attracted much attention because of their unique structures and various reactivity. However, acid/base-free oxoboranes and iminoboranes are still limited, and readily accessible examples with diverse electronic and steric characteristics are highly desirable. Herein, we report the first syntheses of the acyclic anionic oxoborane 2and iminoborane 4bearing two boryl ligands, both of which are acid/base-free. Spectroscopic analysis, X-ray crystallography, and theoretical calculations reveal that 2and 4possess a polarized terminal B═O double bond and central B≡N triple bond, respectively.

Although pincer-type main group complexes have attracted considerable attention owing to their unique structures and intriguing reactivity, the isolation of pincer-type dianionic dialane(6) is still elusive. Herein we report the first synthesis of the dianionic dialane(6) species 4bearing novel redox-active trinitrogen pincer ligands by reduction of the aluminum diiodide precursor 3with excess potassium graphite. The structure of 4has been investigated by spectroscopic analysis, X-ray crystallography, and density functional theory calculations, which reveal that 4possesses an Al–Al single covalent bond and twisted trianionic pincer ligands.