Remove unsupported characters in mysqli with php

I’m developing something simple but it brings me upside down the unsupported characters within a text field in mysqli.

This is the string I’m trying to upload

Gloria Grahame, Lawrence Tierney, Henry Wilcoxon, Edmond O'Brien

I try to remove the character that gives me problems right now which is ‘

$resumen=str_replace("'",'',$_POST[resumen]);

But it doesn’t work, how can I fix? I would like to find a way that removes from the string all the characters not supported by the database