To provide a pharmaceutical composition containing an agonist having high selectivity for an apelin receptor and having an effect of protecting retinal neurons to be damaged by diabetic retinopathy.SOLUTION: The pharmaceutical composition contains as an active ingredient a compound represented by the general formula (I) in the figure. (Ris a C1-6 linear, branched or cyclic alkyl group; R-Rare each independently H or a C1-6 linear, branched or cyclic alkyl group; and Ris an optionally substituted phenyl group or nitrogen-containing heterocyclic group.)SELECTED DRAWING: Figure 14
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