RESUMEN
Plant-based hard capsules have gained considerable attention because of their great properties. Accordingly, designing and developing of these kinds of capsules will be a difficult task. Herein, an innovative pullulan-based hard capsule formulation was prepared for the first time. A series of characterization approaches, including Fourier transform infrared, field emission scanning electron microscope, and rheology analysis, were utilized to figure out the straightforward preparation of a designed hard capsule. Many tests and experiments were performed to achieve the optimum capsule formulation. Based on the obtained results, specifications such as uniform downfall and non-desirable adhesion, and other ideal characteristics of the capsule display the critical function. The gelling promoter of divalent cationic salts is more beneficial than its single-valent counterparts. With respect to the key role of gelling promoter, the presence of chosen MgSO4.7H2O salt and the source of selected carrageenan are important parameters to achieve optimal formulation. Moreover, field emission scanning electron microscope images illustrate that the weight ratio of 3.5 (gelling agent to salt) displays uniform surface morphology without any impurities or other foreign materials. Likewise, the outcomes of the rheology test also illustrated that the weight ratio of 3.5 is preferable. Considering the different weight ratios, the benefits of a weight ratio of 3.5 outweigh the other investigated ratios. Overall, the current research addresses substantial information about developing pullulan-based hard capsules for target usage.
RESUMEN
In this paper, we show a strategy to modify salphen-type Schiff base ligands with naphtol (SYML1) and pyrocathecol (2,3-dihydroxyphenyl) groups (SYML2), or a combination of both (ASYML). Each of these ligands can be used to obtain polynuclear metal complexes following two different strategies. One relies on using metals that are either too large for the N2O2 cavity or not fond of coordination number 4 and the other one relies on forcing the polynuclear species by adding functional groups to the hydroxybenzaldehayde in order to have extra coordination sites in the ligand. We report and characterize the mononuclear complexes SYML1-Cu and SYML1-Ce, along with the dinuclear complex SYML1-Fe and the tetranuclear species SYML2-Mn. The asymmetric ligand ASYML routinely hydrolyzes into the symmetric ligands in the reaction mixtures. SYML1-Fe displays a nearly linear Fe-O-Fe bridge with very strong antiferromagnetic coupling between the Fe(III) ions.