The present invention relates to formulations containing cyclosporin analogs that are structurally similar to cyclosporin A, in particular isomeric mixtures of cyclosporin analogs that are structurally similar to cyclosporin A. The formulations form stable microemulsion preconcentrates and may provide superior drug bioavailability and/or may reduce one or more adverse effects associated with the administration of cyclosporin. Also disclosed are methods for using and preparing the formulations.