ABSTRACT
Bio-adhesive drug delivery system (BDDS) is a novel drug delivery system, which can prolong the retention time of the preparation, improve the stability of the drug, and improve the mucosa absorption and the targeting of the drug. With the development of polymer materials over the past 30 years, BDDS made a great progress. This paper reviews the muco-adhesion theory, adhesive materials, and methods to evaluate muco-adhesive properties and applications in traditional Chinese medicine according to domestic and foreign literatures, in order to provide new ideas for further studies.
ABSTRACT
OBJECTIVE: To explore the effects of different bio-adhesive materials on in vitro adhesion and retention in artificial gastric acid fluid of Panax notoginseng saponins(PNS) bio-adhesive pellets. METHODS: PNS bio-adhesive pellets were prepared with different bio-adhesive materials.The in vitro adhesion of PNS bio-adhesive pellets was determined by the tissue retention method, using HPLC method to determine the contents of PNS(including notoginseng saponins R1, ginseng saponin Rg1 and ginseng saponin Rb1) retained in the pellets after a certain period of time in artificial gastric acid fluid. RESULTS: The contents of PNS retained in PNS bio-adhesive pellets prepared with chitosan and chitosan-carbomer after being placed in artificial gastric acid fluid for 2 h were the largest, which were (27.60±7.45)% and (19.80±3.55)% for R1, (27.01±5.49)% and (19.67±1.39)% for Rg1 and (47.07±6.26)% and (51.08±7.44)% for Rb1, respectively.For in vitro adhesion, HPMC and HPMC-carbomer combination was the best, followed by chitosan and chitosan-carbomer combination. CONCLUSION: PNS bio-adhesive pellets prepared with chitosan and chitosan-carbomer combination bio-adhesive materials can protect PNS from degradation in artificial gastric acid fluid and have good adhesion property.
ABSTRACT
The objectiveness of this study was to evaluate whether low-viscosity composite can bond effectively to dentin surface without bonding resin. The low-viscosity composites being 50wt% filler content were made by the inclusion of bonding resin of two self-etching systems(Clearfil SE Bond, Unifil Bond) varied with contents as 0, 10, 20, 30, 40, 50wt%. Exposed dentin surfaces of extracted 3rd molars are used. Dentin bond strengths were measured. The tests were carried out with a micro-shear device placed testing machine at a CHS of 1mm/min after a low-viscosity composite was filled into an iris cut from micro tygon tubing with internal diameter approximately 0.8mm and height of 1.0mm. 1. Flexural strength and modulus was increased with the addition of bonding resin. 2. Micro-shear bond strength to dentin was improved according to content of bonding resin irrespective of applying or not bonding resin in bonding procedure, and that of Clearfil SE Bond groups was higher than Unifil Bond. 3. There were no significant difference whether use of each bonding resin in bonding procedure for S-40, S-50, U-50(p>0.05). 4. In SEM examination, resin was well infiltrated into dentin after primed with self-etching primer only for S-50 and U-50 in spite of the formation of thinner hybrid layer. Low viscosity composite including some functional monomer may be used as dentin bonding resin without an intermediary bonding agent. It makes a simplified bonding procedure and foresees the possibility of self-adhesive restorative material.