Cyclic organic compounds with several ether linkages in their structure are of much concern in our daily life applications. Crown ethers (CEs) are generally heterocyclic and extremely versatile compounds exhibiting higher binding affinity. In recent years, due to their unique structure, crown ethers are widely used in drug delivery, solvent extraction, cosmetics manufacturing, material studies, catalysis, separation, and organic synthesis. Beyond their conventional place in chemistry, this review article summarizes the synthesis, biological, and potential pharmacological activities of CEs. We have emphasized the prospects of CEs as anticancer, anti-inflammatory, antibacterial, and antifungal agents and have explored their amyloid genesis inhibitory activity, electrochemical, and potential metric sensing properties. The central feature of these compounds is their ability to form selective and stable complexes with various organic and inorganic cations. Therefore, CEs can be used in gas chromatography as the stationary phase and are also valuable for cation chromatographic to determine and separate alkali and alkaline-earth cations.
To look superior and acceptable in society, people from all over the world use various types of cosmetic products to enhance or alter their facial appearance and body texture. In recent times, an exponential surge in cosmetic use has been observed in Pakistan, and hence spending money on personal-care products is high. However, there are many reported facts about high loads of lead, mercury, copper, and others hazardous and cancerous elements in local Pakistani cosmetic brands. Consumers of these brands are at high risk of many clinical issues, including cancer. As such, it is a necessity to make people aware of the devastating harmful effects related to cosmetic use. The aim of this study was to provide information for stakeholders and raise awareness in the general public about the use of these local unauthorized personal-care cosmetic products, along with government strategies to stop this cosmetic blight on human health.
The present study deals with the isolation and modification of Salvia spinosa hydrogel (SSH) to investigate its thermal degradation profile. The SSH was modified chemically to its acetylated derivative (ASSH-1–4) with DS 1.05-2.79. After characterization by Fourier transform infrared (FTIR) and solid-state CP/MAS 13C-NMR spectroscopic techniques, both SSH and ASSH-4 were subjected to thermogravimetric analyses (TG) by the isoconversional method, i.e., the Flynn-Waal-Ozawa (FWO) and the Kissinger methods. TG curves showed that both SSH and ASSH-4 exhibited two-step degradation. The energy of activation (Ea) for each degradation step was calculated by fitting thermal degradation data to the FWO method, revealing greater stability of ASSH-4 than that of SSH. Analysis by Kissinger’s method revealed the second and one and a half order of thermal degradation (n) for SSH and ASSH-4, which also evidenced that ASSH-4 is more stable than SSH. The values of the thermodynamic triplet (ΔH, ΔG and ΔS) were calculated from thermal data. Positive values were found for ΔG, which showed the non-spontaneous nature of thermal degradation of SSH and ASSH-4. The values of integral procedural decomposition temperature (IPDT) and intrinsic thermal stability (ITS) for SSH and ASSH-4 were found comparatively greater than those of many other commercially available materials of the same kind, which revealed the higher stability of both materials. SSH, as a benign polysaccharide-based material, was also assessed for its utility in drug release studies, taking caffeine as a model drug. The SSH matrix-based tablet formulation (SSHC) showed a sustained release behavior of the drug in preliminary studies.
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