Preparation of cationic functional polymer poly(Acryloxyethyltrimethyl ammonium chloride)/SiO2 and its adsorption characteristics for heparin

Modified Diatomaceous Earth in Heparin Recovery from Porcine Intestinal Mucosa

Heparin, a highly sulfated glycosaminoglycan, is a naturally occurring anticoagulant that plays a vital role in various physiological processes. The remarkable structural complexity of heparin, consisting of repeating disaccharide units, makes it a crucial molecule for the development of commercial drugs in the pharmaceutical industry. Over the past few decades, significant progress has been made in the development of cost-effective adsorbents specifically designed for the adsorption of heparin from porcine intestinal mucosa. This advancement has been driven by the need for efficient and scalable methods to extract heparin from natural sources. In this study, we investigated the use of cationic ammonium-functionalized diatomaceous earth, featuring enhanced porosity, larger surface area, and higher thermal stability, to maximize the isolated heparin recovery. Our results showed that the higher cationic density and less bulky quaternary modified diatomaceous earth (QDADE) could adsorb up to 16.3 mg·g-1 (31%) of heparin from the real mucosa samples. Additionally, we explored the conditions of the adsorbent surface for recovery of the heparin molecule and optimized various factors, such as temperature and pH, to optimize the heparin uptake. This is the introductory account of the implementation of modified diatomaceous earth with quaternary amines for heparin capture.

Efficient and Economic Heparin Recovery from Porcine Intestinal Mucosa Using Quaternary Ammonium-Functionalized Silica Gel

Heparin, usually isolated from porcine intestinal mucosa, is an active pharmaceutical ingredient of great material value. Traditionally, diverse types of commercial resins were employed as an adsorbent for heparin retrieval from biological samples. However, more recent years have encouraged the advent of new cost-effective adsorbents to achieve enhanced heparin retrieval. Inexpensive cationic ammonium-functionalized silica gels, monodispersed with larger surface area, porosity, and higher thermal stability, were chosen to evaluate the heparin recovery yield from porcine intestinal mucosa. We demonstrated that higher positively charged and less bulky quaternary modified silica gel (e.g., QDASi) could adsorb ~28% (14.7 mg g-1) heparin from the real samples. In addition, we also determined suitable surface conditions for the heparin molecule adsorption by mechanistic studies and optimized different variables, such as pH, temperature, etc., to improve the heparin adsorption. This is going to be the first reported study on the usage of quaternary amine-functionalized silica gel for HEP uptake.

Synthesis of Cross-Linked Spherical Polycationic Adsorbents for Enhanced Heparin Recovery

Heparin, as an anticoagulant drug, is almost entirely produced via isolation from mucosal tissues of different animals; therefore, it is it is crucial to maximize its recovery. Adsorption of heparin from this complex biological mixture needs a specialized and highly effective adsorbent that almost separates only heparin from the mixture. In this work, a series of spherical cross-linked polymer bead adsorbents were synthesized via inverse suspension polymerization of water soluble monomers in corn oil, a benign solvent, and their performance for heparin adsorption from a biological sample of porcine mucosa was evaluated. To tune the performance and swelling of the resins, we varied the molar ratio of the monomer(s) to the cross-linker as well as the molar ratio of the monomers. The results of heparin recovery from biological porcine mucosa show that our optimized resin can outperform the commercially available resin in terms of adsorption efficiency of up to 18%. The adsorbed heparin was eluted, isolated, and its anticoagulant potency measured using the standard sheep plasma clotting assay. The isolated heparin samples were also analyzed by ¹H NMR spectroscopy to check the possible impurities, and the results show the presence of chondroitin sulfate and dermatan sulfate, as is the case for the heparin eluted from the commercial resin. Furthermore, the effects of some experimental variables including the adsorbent dosage, pH, time, and recycling on heparin adsorption were studied, and the results show that these resins can be used for efficient recovery of heparin.

Selective Electrochemical Capture and Release of Heparin Based on Amine-Functionalized Carbon/Titanium Dioxide Nanotube Arrays

Heparin (HEP) is a sulfated glycosaminoglycan that is a clinical anticoagulant agent. Commercially derived from porcine intestinal mucosa, HEP is challenging to separate from this complex biological mixture for additional purification. This study aimed to raise the purity of isolated HEP using electrochemical potential to increase its selective capture and release. We demonstrate an electrochemical platform featuring an anode composed of amine-functionalized carbon/titanium dioxide nanotube arrays on titanium foil (Ti/C-TNTAs-NH₂) and a cathode made of expanded graphite. Our results show that Ti and Ti/C-TNTAs control plates do not adsorb HEP, even while applying an external potential to the cell. However, when the Ti/C-TNTAs electrode is modified by 3 aminopropyltriethoxysilane, the terminal NH₂ groups provide a high density of positive charges that serve as binding sites, enabling the adsorption of HEP. This attraction is further strengthened by applying an external potential to the anode. Subsequent release of the HEP molecules and regeneration of the Ti/C-TNTAs-NH₂ electrode are easily accomplished by applying an anodic potential to the plate, as well as by increasing the concentration of NaCl in solution. This electrochemical system demonstrates the good selectivity of HEP, even within a mixture of other probable interfering species (e.g., bovine serum albumin and chondroitin sulfate). Additionally, it maintains 90.11% of its initial electrosorption efficiency after ten repeated HEP adsorption/desorption cycles, indicating this system's promising stability and reusability for HEP purification.