Preparetion Of Alkyl-Pection As A Drug Carrier For Colon-Specific Delivery

Pectin (PT) is a natural anion polysaccharide. As a biocompatible and degradable polymer, pectin has been widely used in drug delivery systems (DDS) especially in drug-controlled release, targeting, and intellectualized delivery system. Taking bovine serum alumin (BSA) as a drug model, the tablets of alkyl-pectin were prepared as skeleton materials for colon-specific delivery (BSA-CSD), and the releasing property was evaluated in vitro.Alkyl-pectin was prepared by the reaction of pectin and multi-kinds of alkyl-bromide in alkaline solution, and the degree of substitution of alkyl-pectin was tested by the methods of elementary analysis. Infrared (IR) spectra of alkyl-pectin revealed that there was a substitution reaction mainly on the hydroxy groups and carboxyl of PT. The alkyl-pectin structure are characterized byFT-IR,EL,DSC and ~1H NMR analysis.pH-sensitive hydrogels based on chitosan-pectin (CS-PT) and chitosan-octyl-pectin were synthesized by using glutaradehyde as cross-linker. The influence of condition of synthesis to the swelling ratio of these two kinds of hydrogels was studied. The effects of the degree of the dosage of crosslinking, pH, and ionic strength on the swelling behaviors of two kinds of hydrogels were studied, and the swelling ratio (SR) of this hydrogel in acide solution is much larger than that in alkaline solution. The release behavior of bovine serum alumin entrapped in the hydrogels was of distinctly difference with the changes of pH value of loading medium. The release of bovine serum alumin in those two kinds of hydrogels in the medium of pH 1.0 was much quicker in pH 7.4 and 9.18.The effects of different pH of different media, rotational speeds, compaction pressures and degree of substitution on dissolution rates were studied. The releasing property of the preparation was evaluated by the dissolution tests in vitro through measuring the content of BSA. The results showed the BSA sustained-releasing tablet kept releasing for 24h in phosphate buffer solution at pH 7.8, while hardly released any in the environment at pH<6.8. The accumulating releasing rate was above 96%. The different rotational speeds and compaction pressures made significant difference to the releasing rate in phosphate buffer solution at pH 7.8. The BSA-CSD was prepared and the preparation could fulfill the aim of delivering in the specific colon in vitro.