Study On The Preparation And Release Behavior Of The Light-sensitive ZnAl-LDH Drug Release System

Layered Double Hydroxide(LDHs)consist of two or more metals.LDHs are a kind of inorganic nonmetallic materials that have attracted much attention,because of their positive electric properties,interlayer anions,exchange ability.The effective release of drug molecules can be achieved by the interaction between the layered plates and drug molecules,which can be used in medicine.The preparation of sustainedrelease drug carriers with LDH as the construction unit is in line with the actual needs and has important academic value.In this paper,ferulic acid(FA)was used as the intercalation drug,4-hydroxyazobenzene(PHAB)was the photoresponsive substance,and zinc-LDH was the lamellar carrier.Photosensitive zinc-LDH drug sustained-release carriers were prepared by coprecipitation method.The effects of synthesis conditions on the controlled-release effect of nanocomposite drugs were systematically investigated.Simulated studies were carried out on the sustained-release mechanism:(1)Drug sustained-release carriers were prepared by coprecipitation method.The effects of pH,PHAB and FA ratio on the structure of drug sustained-release carriers were studied.The samples were characterized by SEM,XRD,UV-Vis and FT-IR.(2)The release behavior of the prepared ZnAl-(FA+PHAB)-LDH under different illumination conditions was studied.The results showed that the slow release behavior of the synthesized ZnAl-(FA+PHAB)-LDH had no obvious change under different pH conditions.With the increase of PHAB content,the final release rate of the synthesized ZnAl-(FA+PHAB)-LDH(0.2)under ultraviolet irradiation was the highest,reaching 94%.In addition,the release time of ZnAl-(FA+PHAB)-LDH under ultraviolet irradiation was longer than that under natural illumination at the same release rate.After balance,the final release rate of ZnAl-(FA+PHAB)-LDH was approximately equal under different illumination conditions.(3)The slow-release behavior of the prepared carrier was fitted by kinetics,and its slow-release behavior and mechanism were analyzed.The results showed that the slow-release behavior of the synthesized ZnAl-(FA+PHAB)-LDH under different pH conditions under different light conditions belonged to Fick diffusion;when the content of PHAB increased,the slow-release behavior of ZnAl-(FA+PHAB)-LDH under natural light belonged to Fick diffusion and skeleton dissolution,and under ultraviolet light.The sustained-release behavior of the drug is more in line with the zero-order kinetics and belongs to the role of skeleton dissolution.