Study Of The Synthesis And Bioactivity Of Iodine Encapsulated In Cyclodextrin

The iodine encapsulated in cyclodextrin is an iodine product developed to improve iodine in the application of irritating odor,high yellow dyeing rate,rapid loss of effective iodine content,and low biocompatibility.Compared with the existing iodine disinfectants on the market,the product has little difference in antibacterial and antiviral properties,but cyclodextrin is an environmentally friendly and new natural reproduction material.It can greatly reduce the cost of production,storage,and transportation of iodine products and increase the scope of application of iodine.In addition,the inclusion complex has also shown good application prospects in medicine,food,agriculture,animal husbandry,aquaculture and applied chemistry.Based on this,cyclodextrin was chosen as a new type of iodine-containing material.Firstly,the preparation conditions of iodine encapsulated in cyclodextrin were optimized by the saturated aqueous solution method.Interaction factors were analyzed by response surface experiments.Then,the inclusion of inclusion complexes was verified by infrared spectroscopy,thermogravimetric analysis and nuclear magnetic resonance spectroscopy.Finally,the stability and antibacterial activity of the prepared clathrate were analyzed.The main work contents and work results of this paper are as follows.?1?The amount of potassium iodide added was 2.0 g by consulting a large amount of literature and combining preliminary experiments to optimize potassium iodide as a co-solvent for iodine.The saturated aqueous solution method was used to prepare the iodine encapsulated in cyclodextrin.?2?Explore the effect of various factors on the effective iodine content in iodine encapsulated in cyclodextrin through a series of single-factor experiments.The effective iodine content in the inclusion complex and the inclusion complex ratio of the inclusion complex were used as evaluation indicators to optimize the preparation process,and the most significant three factors were selected to conduct response surface experiments.The experimental results show that the optimal preparation process parameters are:ratio of material to solute 1.12:1,reaction temperature59.19?,pH value 6.89,reaction time 2 h and stirring speed 300 r/min.For 19.823%.?3?The prepared inclusion complexes were analyzed by Infrared spectroscopy?FT-IR?,thermogravimetric analysis?TGA?and nuclear magnetic resonance spectroscopy(¹H-NMR and ¹³C-NMR).Infrared spectroscopy showed that the characteristic peaks of iodine disappeared before inclusion in inclusion complexes;The peaks of the water molecules in the cavity of the cyclodextrin decrease;Denotes a decrease in the peak pattern of the-CH₂ group on the C-6 position of the cyclodextrin.The reason for the analysis is that after the inclusion of iodine and cyclodextrin,iodine molecules enter the cyclodextrin cavity.At this time,the water molecules in the cavity are squeezed out of the cavity,so the characteristic peak of iodine disappears;Studies have shown that inclusion of iodine and cyclodextrin can cause a corresponding deflection of the-CH₂ group at the C-6 position of the cyclodextrin.In addition,observation of changes in the peaks represented by their?-1,4 glycosidic bonds before and after inclusion showed that they did not change.Therefore,we believe that inclusion of inclusion complexes does not cause changes in the cyclodextrin skeleton.The thermo-gravity curve shows that the weight loss of cyclodextrin is divided into two stages,which are 30¹18? and 325?⁶00?.The former is the loss of water in the cyclodextrin cavity?loss rate:8.73%?;the latter is due to the decomposition of cyclodextrin.The loss of iodine/cyclodextrin inclusions can also be divided into two stages,followed by 30¹70? and 170⁶00?.The former indicates the loss of iodine and water molecules in the cyclodextrin cavity,and the latter is attributed to the collapse of the cyclodextrin backbone.¹H-NMR showed that the chemical shifts of H-3,H-5,and H-6 protons in the cyclodextrin cavity shifted significantly after inclusion.They shifted by 0.014 ppm.0.013 ppm and 0.010 ppm.The main reason is that H-3 and H-5are inside the cyclodextrin cavity,and the iodine molecules enter the cavity and cause changes in H-3 and H-5.The change in H-6 shift was attributed to the inclusion of iodine and cyclodextrin that caused the-CH₂ group on the H-6 position of the cyclodextrin to deflect.This result is justified by the infrared result.Nuclear magnetic resonance spectroscopy(¹³C-NMR)showed that the displacement of the cyclodextrin carbon skeleton before and after the inclusion of the inclusion compound did not change.For this reason,we conclude that inclusion of iodine and cyclodextrin does not cause changes in the cyclodextrin carbon skeleton.?4?Validation of the prepared inclusion compound by effective iodine and free iodine found that the inclusion compound contained effective iodine and there was no free iodine.The solid inclusion complex was subjected to a stability test to investigate its storage under natural storage conditions for 1 year with a loss of 1.15%of the effective iodine content.The effect of storage temperature,light and relative humidity on the iodine encapsulated in cyclodextrin within 10 days of storage was investigated using a physical mixture of iodine-cyclodextrin as a control.The results showed that compared to the physical mixture,the effective iodine in the inclusion complex was compared.The content loss rate is significantly reduced.The combination of the three results suggests that the prepared clathrate should be stored in a dark,closed and dry environment.povidone-iodine as a control to explore the antibacterial activity of the inclusion complexes,The experimental results showed that when the effective iodine content was 0.5 wt%,it showed significant inhibition of Escherichia coli and Staphylococcus aureus.The bacteriostasis effect compared with the equal weight percentage of povidone-iodine,The antibacterial effect increased with the increase of the effective iodine content.