I used to use it as a single excipient in the formulation of suppositories, and sometimes with Ovucire. But I didnt't try to use it in the formulation of microemulsions. In case of microemulsions. I think Gelucire® 44/14 works well. As you know, it is a nonionic water-dispersible surfactant, obtained by polyglycolysis of hydrogenated coconut oil with PEG-32. It has a high HLB (14), therefore it can be used either alone or as part a self emulsifying formulation (SEDDS/SMEDDS).