diff --git a/qpms/cymaterials.pxd b/qpms/cymaterials.pxd
index 6ce8984..7e499bf 100644
--- a/qpms/cymaterials.pxd
+++ b/qpms/cymaterials.pxd
@@ -18,7 +18,7 @@ cdef class MaterialInterpolator:
     cdef readonly double omegamin
     cdef readonly double omegamax
     cdef inline void *rawpointer(self):
-        return <void *>&(self.interp)
+        return <void *>(self.interp)
 
 cdef class EpsMu:
     cdef public qpms_epsmu_t em