Gelatin is a protein extracted from the connective tissues of animals such as skin, bones, and tendons. It is mainly formed by partially hydrolyzing collagen and possesses various properties such as gel-forming ability, thermally reversible nature, and biocompatibility. It is widely used in industries such as biomedicine, pharmaceuticals, and food processing.
Hyaluronic acid (also known as hyaluronic acid) is a linear polysaccharide that is widely present in human and animal tissues. It is mainly composed of alternating connections of D-glucuronic acid and N-acetylglucosamine, and this structure endows hyaluronic acid with excellent water retention properties and biocompatibility. It can be widely applied in the fields of medicine, cosmetics, and beauty.
Due to its poor mechanical strength, rapid degradation rate and poor thermal stability, it is restricted from being directly applied in biomedical filling. Therefore, cross-linking modification is carried out on it to enhance its mechanical strength and anti-degradation performance.
The common methods can be classified into chemical cross-linking modification and enzymatic cross-linking modification.
After the crosslinking reaction is completed, the remaining crosslinking agents and quenching agents may cause cytotoxicity or other adverse reactions, affecting the safety and functionality of the product. As a key impurity in the crosslinking process, it is necessary to remove the crosslinking agents to meet the quality standards.
The common methods for removing residual cross-linking agents include: dialysis method, organic solvent extraction method and ultrafiltration method, etc.
The dialysis method is simple to operate but takes a long time and has low efficiency; the organic extraction method is effective in removing certain cross-linking agents, but it also introduces the problem of solvent residue.
The ultrafiltration method has the advantages of high separation efficiency and short processing time. Besides removing small molecules such as cross-linking agents, it can also concentrate the material solution to the target concentration. There are various types and models of ultrafiltration membranes, including inorganic ultrafiltration membranes and organic ultrafiltration membranes, with a molecular weight cut-off range from 1KD to 800KD.
After cross-linking with hyaluronic acid, both gelatin and hyaluronic acid exhibit the characteristics of wide molecular weight distribution and high solution viscosity. Usually, the material of the membrane, the form of the membrane element, and the membrane accuracy are determined based on the material concentration and the target concentration.
Wuhan Bona is dedicated to applying membrane filtration for the separation and purification of materials. It has accumulated rich experience in removing various molecular weight ranges of gelatin, collagen, hyaluronic acid, and modified cross-linking agents. Based on the type, properties, molecular weight, target concentration, cross-linking agent type, and endpoint indicators of the customer's products, it can determine the appropriate membrane elements, membrane equipment, and removal process to replace dialysis bags. It provides customers with pilot production, production processes, and equipment, helps them solve process problems, and gains industry recognition.
