Sherriff M, Enever R P
J Pharm Sci. 1979 Jul;68(7):842-5. doi: 10.1002/jps.2600680714.
The rheological properties of oil gels prepared by dispersing colloidal silica in n-dodecane and 1-dodecanol were examined. The differences in gel strength using these two media were accounted for by the difference in the extent of hydrogen bond formation between the silanol groups on the silica surface. The incorporation of methyl salicylate further modified the rheological properties of the gels. The drug was capable of hydrogen bonding with silanol groups in the n-dodecane gels, which increase gel strength at low concentrations; at high concentrations, the drug acted as a plasticizer. In 1-dodecanol systems, the drug acted solely as a plasticizer. Adsorption studies showed that methyl salicylate was adsorbed only on the silica particles in the n-dodecane medium. Interaction of the drug with the silanol groups in the n-dodecane systems did not appear to effect methyl salicylate release from the gels.
研究了通过将胶体二氧化硅分散在正十二烷和1-十二烷醇中制备的油凝胶的流变特性。使用这两种介质时凝胶强度的差异是由二氧化硅表面硅醇基团之间氢键形成程度的差异造成的。水杨酸甲酯的加入进一步改变了凝胶的流变特性。该药物能够与正十二烷凝胶中的硅醇基团形成氢键，在低浓度时增加凝胶强度；在高浓度时，该药物起到增塑剂的作用。在1-十二烷醇体系中，该药物仅起到增塑剂的作用。吸附研究表明，水杨酸甲酯仅吸附在正十二烷介质中的二氧化硅颗粒上。在正十二烷体系中，该药物与硅醇基团的相互作用似乎并未影响水杨酸甲酯从凝胶中的释放。
