Study On The Expansion Of Shrimp And Crab Shell Material Into Natural Template Nanopore And Slow Release Controlled Drug Carriers

A slow release carrier refers to a material that is released at a set time and speed to maintain its effective concentration.It can be widely used in animals,plants and microorganisms.The most important thing is to control the speed,time and location of drug.Drug sustained-release carrier affects the way and diffusion of drug into animals and plants,and has a significant control effect on the speed and concentration range of drug release and enhances the drug absorption effect.Sustained-release drug carrier can reduce the frequency of drug change and dosage,has less toxic and side effects,and obviously enhances the efficacy of the drug,and is an important direction for drug development.The slow-release carrier is the key material.Although there are many studies,there are a series of problems such as poor performance stability,short controlled release time,high production cost,and poor product safety,which have not yet become mainstream.Although chitosan composites,porous chitosan,porous CaCO3,and chitosan-CaCO3 composites have been studied as adsorption carrier materials,most of them remain in the laboratory stage.It has not been reported that the natural nanopore of shrimp and crab shells can be directly used as a template or be retained and expanded its nanopore by removing structural substances.In this paper,the intermediates and main by-products obtained in the innovative process of synthesizing carboxymethyl chitosan by alkali deproteinization and further derivatization in the alcohol-water system developed by our group were used.The chitosan-CaCO3 complex,the chitin-protein complex,and the porous CaCO3 were evaluated for drug loading test and sustained release effect,and satisfactory results were obtained.The highlight of this paper is the invention of a powder material with natural nanopore template such as shrimp and crab shell.After simple processing or further expansion,a slow release carrier with different characteristics of natural nanopore series is obtained,and various preparation and drug loading methods were developed.We have studied the shrimp and crab shell powder obtained by simple powder processing or alkali or acid treatment,deproteinized chitosan-CaCO3 powder,bio-CaCO3 after separation of carboxymethyl chitosan or a composite bio-based material of chitin and protein which directly removes CaCO3 by acid has the ideal drug-loading and sustained-release ability.The SEM,pore size,pore volume,BET,TEM,elemental analysis,FT-IR,SDT-Q600 and other analytical instruments were used to characterize and structure the product,demonstrating its natural porosity.The release effects of different substances were evaluated by dialysis membranes.The loading and release curves of different carrier materials in different systems were determined by spectrophotometry or high performance liquid chromatography.It was proved that some carriers had better slow release effect than free drugs and pharmacopoeia.The product characterization and structure analysis showed that all materials except chitin and protein composites have pore structures within 10 nm of average pore diameter,and the specific surface area is increased by more than 10 times than the raw material.By heating,drying and adding different solvents to adsorb or decompression at the same time,the adsorptive capacity of different carriers is different,up to 40%.Some carriers do meet the requirement of slow release of more than 70%of the drug for more than 10 hours,and the release of controlled release pesticide can be more than 70%for up to 15 days.These four bio-based materials and bamboo fibers with natural nanopores are rich in raw materials,simple in preparation,low in production cost,non-toxic and edible,environmentally friendly and fully biodegradable,and capable of adsorbing and storing functional chemistry including various drugs in solution.They have ideal conditions for the development of controlled-release carrier materials.It will be widely applied in the fields of slow and controlled release drugs,pesticides,plant growth regulation,bacteriostatic preservation,flavors and fragrances,and environmental treatment and so on.