Anionic species from multivalent metal salts are differentially retained during aqueous ionic gelation of sodium alginate and could fine-tune the hydrogel properties.

The role of anionic counterions of divalent metal salts in alginate gelation and hydrogel properties has been thoroughly investigated. Three anions were selected from the Hofmeister series, namely sulphate, acetate and chloride, paired in all permutations and combinations with divalent metal cations like calcium, zinc and copper. Spectroscopic analysis revealed the presence of anions and their interaction with the respective metal cations in the hydrogel. The data showed that the gelation time and other hydrogel properties were largely controlled by cations. However, subtle yet significant variations in viscoelasticity, water uptake, drug release and cytocompatibility properties were anion dependent in each cationic group. Computational modelling based study showed that metal-anion-alginate configurations were energetically more stable than the metal-alginate models. The in vitro and in silico studies concluded that acetate anions preceded chlorides in the drug release, swelling and cytocompatibility fronts, followed by sulphate anions in each cationic group. Overall, the data confirmed that anions are an integral part of the metal-alginate complex. Furthermore, anions offer a novel option to further fine-tune the properties of alginate hydrogels for myriads of applications. In addition, full exploration of this novel avenue would enhance the usability of alginate polymers in the pharmaceutical, environmental, biomedical and food industries.

Binder jet 3D printing composite bilayer tablet of extended-release printing technology in the study / 药学学报

Based on the dual needs of analgesia and anti-inflammation in trauma treatment, this study uses acetaminophen and moxifloxacin hydrochloride as active pharmaceutical ingredients and develops a composite bilayer tablet with a dual-phase drug release system by using binder jet 3D printing technology. Due to the complexity of the 3D printing process, there is an interaction between the various parameters. Through the optimization of the process, the relationship between the key process parameters can be determined more intuitively. In this study, the process of extended-release tablets was optimized to maintain the mechanical properties of the tablets while realizing the regulation of release. The full-factor experimental design of three central points 23 was used to analyze the factors that significantly affect the quality attributes of extended-release tablets and the interaction between factors. The optimal extended-release process parameters were obtained by the response optimizer: the inkjet quantity of the printing ink was 10 (about 13.8 pL), the powder thickness was 180 μm, and the running speed was 360 mm·s-1. The in vitro of release of 3D printed composite bilayer tablets showed that the in vitro of release of 3D printed tablets and commercially available tablets conformed to the Ritger-Peppas release model. The results of porosity showed that the immediate-release layer of the preparation has many pores and large pore size, and the dissolution of the immediate release layer within 15 min was greater than 85%. The internal pore size of the extended release layer is large, but it can still release slowly for up to 8 h, the mechanism may be related to the extended release of HPMC gelation. On the basis of verifying the rationality of the design goal of 3D printed composite bilayer tablets, this study also provides a theoretical basis for the preparation of 3D printing complex preparations.