Fluorescent and Phosphorescent Nitrogen-Containing Heterocycles and Crown Ethers: Biological and Pharmaceutical Applications.

Fluorescent molecules absorb photons of specific wavelengths and emit a longer wavelength photon within nanoseconds. Recently, fluorescent materials have been widely used in the life and material sciences. Fluorescently labelled heterocyclic compounds are useful in bioanalytical applications, including in vivo imaging, high throughput screening, diagnostics, and light-emitting diodes. These compounds have various therapeutic properties, including antifungal, antitumor, antimalarial, anti-inflammatory, and analgesic activities. Different neutral fluorescent markers containing nitrogen heterocycles (quinolones, azafluoranthenes, pyrazoloquinolines, etc.) have several electrochemical, biological, and nonlinear optic applications. Photodynamic therapy (PDT), which destroys tumors and keeps normal tissues safe, works in the presence of molecular oxygen with light and a photosensitizing drugs (dye) to obtain a therapeutic effect. These compounds can potentially be effective templates for producing devices used in biological research. Blending crown compounds with fluorescent residues to create sensors has been frequently investigated. Florescent heterocyclic compounds (crown ether) increase metal solubility in non-aqueous fluids, broadening the application window. Fluorescent supramolecular polymers have widespread use in fluorescent materials, fluorescence probing, data storage, bio-imaging, drug administration, reproduction, biocatalysis, and cancer treatment. The employment of fluorophores, including organic chromophores and crown ethers, which have high selectivity, sensitivity, and stability constants, opens up new avenues for research. Fluorescent organic compounds are gaining importance in the biological world daily because of their diverse functionality with remarkable structural features and positive properties in the fields of medicine, photochemistry, and spectroscopy.

Fabrication and in vitro evaluation of chitosan-gelatin based aceclofenac loaded scaffold.

Scaffold development is a nascent field in drug development. The scaffolds mimic the innate microenvironment of the body. The goal of this study was to formulate a biocompatible and biodegradable scaffold, loaded with an analgesic drug, aceclofenac (Ace). The bioscaffold is aimed to have optimum mechanical strength and rheology, with drug released in a sustained manner. It was prepared via chemical cross-linking method: a chitosan (CS) solution was prepared and loaded with Ace; gelatin (GEL) was added and the mixture was cross-linked to get a hydrogel. 20 formulations were prepared to optimize different parameters including the stirring speed, drug injection rate and crosslinker volume. The optimal formulation was selected based on the viscosity, drug solubility, homogeneity, porosity and swelling index. A very high porosity and swelling index were attained. In vitro release data showed sustained drug delivery, with effective release at physiological and slightly acidic pH. SEM analysis revealed a homogeneous microstructure with highly interconnected pores within an extended polymer matrix. FT-IR spectra confirmed the absence of polymer-drug interactions, XRD provided evidences for efficient drug entrapment within the scaffold. Rheological analysis corroborated the scaffold injectability. Mathematical models were applied to in-vitro data, and the best fit was attained with Korsmeyer-Peppas.