61A-24 |
Preparation of tripolyphosphate-chitosan microspheres for the controlled release of drug |
J. A. KO and H. J. Park. Graduate School of Biotechnology, Korea University, 1, 5-ka, Anam-dong, Sungbuk-ku, Seoul, 136-701, South Korea Chitosan has been extensively studied as drugs carriers in the pharmaceutical industry. In previous studies, drug release from chitosan microspheres could be controlled by crosslinking the matrix using chemical crosslinking agents such as glutaraldehyde and NaOH. However, these chemical crosslinking agents possibly induce undesirable effects. To overcome these disadvantages of chemical cross-linking, we used ionic crosslinking agent, tripolyphosphate (TPP). Our objectives were to study the release behavior of durg from TPP-chitosan microspheres prepared by various factors such as concentration and molecular weight chitosan, pH and concentration of TPP solution and curing time. Chitosan solution was prepared by dissolving in acetic acid. Model drug, felodipine, was dissolved in CH2Cl2 due to water-insoluble (2:10) and then this oil phase was mixed aqueous phase, chitosan solution, by homogenizer; the ratio of oil and aqueous phase was 1:10. O/W emulsions were dropped into TPP solutions by spray gun. After crosslinking time, the microspheres were washed and vacuum dried. We determined the morphological characters, encapsulation efficiency and release rate. The particle size of TPP-chitosan microspheres were mainly between mainly between 500 and 710 зн. The encapsulation efficiencies of chitosan microspheres were more than 90%. The pH and concentration of the closslinking agent solution, molecular weight and concentration of wall material and curing time played an important role on the TPP-chitosan matrix density. As the molecular weight and concentration of chitosan and curing time increased, the release rates of felodipine were significantly decreased. Also, using lower pH and higher concentration of TPP solution resulted in slower felodipine release from microspheres. The pH and concentration of TPP solution, molecular weight and concentration of chitosan solution and curing time played an important role on the TPP-chitosan matrix density that has an effect on the control release of drug.
Session 61A, Carbohydrate
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