Study Of The Release Kinetics Of The Colon Of Small Molecule Drug

The good performance of pharmacokinetic properties is determined by itsspecific molecular weight and easy to free nature.The aspirin(180.16, watersolubility[80])and vitaminC(176.13, soluble)were selected as the modle of waterinsoluble and water soluble drugs in this subject.The releationship between the drugsrelease, the types of coating materials and thickness of film were studied byexamining the release of coated tablets of water soluble and insoluble drugs whichcoated with enteric dissolution materials in colon environment.This thesis consists of three parts.The phenomenon of polyacrylic acid resinfree film’s swelling absorbent and corrosion were examined in the first part, and thesurface dissolution of the film was observed by the use of scanning electronmicroscopy.The reault showed as follow:the water absorption of free film in thesimulated gastric environment maintained at10%to20%,the quality changes afterthe process of absorbing was more than80%, the moisture within in the film is lessthan20%of the weight of the film.A liner relationship can be found between thedissolution rate of the film and the time, the average dissolution rate in simulatedintestinal and colonic environment as follow:2.14×10-5and5.11×10-5.In the second part the aspirin and vitaminC were used as the represents of waterinsoluble and water soluble drugs,the controlled-release tablets were made.The drugrelease and the relationship between the release and the thickness of film werestudied.Then,the release equation of different coating prescription of non-watersoluble drugs in the colon environment was gotten:y=px+q;The release of drug wasliner with time.The release equation different coating prescription of water solubledrug as follow:y=uLn(x)+v(p,q,u,v are constants).The result showed that the twodrugs’ release equation have a certain similarity in the colon,and the coating thickness is the key factor of the drug release.The drug release theory of different thickness of coating tablets’ film were founded by studying the relationship between the dissolution of flim and the drug release.The equation which represented the relationship had been worked out.The equation of the insoluble drugs is that;the equation of water soluble as follow The release between the dissolution of film thickness and the drug release of different nature was studied.The drug release range was set in10%to75%,the time of drug release in colon was defined at the range of240min-285min.The thickness of insoluble drugs in colon release was gotten by using the above equation in this time range as:0.201mm≤h≤0.267mm;the thickness range of soluble drugs is0.202mm≤h≤0.260mm,respectively.The results showed that the film thickness is basically the same and the error is less than2.62%.The reliable film thickness theoretical of small molecule can be used in industrial production.