| Pectin is one of natural macromolecular compounds,the molecular weight of which has a profound impact on the performance of gel beads.The efficient Ca2+ and temprature are important factors of gel formation of low methoxyl pectin.Therefore,the aim of the present study was to investigate the influence of pectin with different molecular weight on the gel beads loading ketoprofen and curcumin,as well as explore the effects of lecithin,Ca2+ concentration,and drug on the rheology properties of gel,which has important significance to explore the formation of the gel beads.The molecular weight of 14.72×104 of B pectin and the molecular weight of 4.48×104 of C pectin were produced from the molecular weight of 12.69×104 of material A pectin by alcohol deposition method.As a result of the viscometric analysis,pectins in the aqueous solution showed polyelectrolyte behavior,whereas intrinsic viscosity[?]was got when dissolved in NaNO3 soution that the[?]of A pectin is 1.32dL/g,and B pectin is 1.55dL/g as well as C pectin is 0.59dL/g.Then the viscosity average molecular weight was obtained though Huggins polt.of which A pectin.B pectin and C pectin is 3.34×104,4.43×104 and 1.37×104 respectively.Gel beads were prepared by pectin with different molecular weight,founding that the surface and section of A gel beads that close to the ball were more smooth and tightness than C gel beads,but there was no significant difference to the drug release.This study was to investigate the lecithin addition,CaCl2 concentration and pH,ketoprofen/pectin ratio on properties of different pectin beads loading ketoprofen.Lecithin was found to decrease the drug loading of all gel beads but enhance entrapment efficiency that A gel beads increased from 72.91%to 88.75%,and B gel beadsand C gel beads increased to 86.10%and 91.01%respectively.Drug loading and entrapment efficiency were low at too high or low CaCl2 concentration,but they were higher with lower pH.As ketoprofen/pectin ratio increased,the drug loading washigher,whereas entrapment efficiency first rised then fell.All factors had no obvious effect on drug release.When exploring the lecithin addition and CaCl2 concentration on properties of different pectin beads loading curcumin,the result showed that drug loading decreased with the increasing amount of lecithin,but entrapment efficiency of Agel beads increasd from 73.06%to 84.48%,as well as C gel beads was 78.59%with lecithin.Entrapment efficiency attained maximum value at moderate CaCl2 concentration.However lecithin and CaCl2 concentration had no obvious effect on drug release.As a result of the rheological properties of pectin gel,the lecthin significantly affected the structure development rate(SDR)and storage modulus(G')during pectin calcium gel formation.The storage modulus(G')and structure development rate(SDR)were largest,as well as loss tangent tan ? curves was lowest.And the scanning electron microscopy showed that the three-dimensional network structure of pectin calcium gels with 10%lecithin added was characterized by greater uniformity and compactness after being subject to the vacuum freeze drying treatment.Compared with without drugs,adding drugs the storage modulus(G')and complex viscosity(?*)of the gel had declined,which suggested a certain amount of drugs against the formation of pectin calcium gel;With higher concentration of CaCl2,the storage modulus(G')and complex viscosity(?*)of the gel is larger,konwing that the high concentration of CaCl2 was conducive to improve the formation of pectin gel. |
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