What is the difference between eudragit RS PO and eudragit RL PO?

Solid substances obtained from EUDRAGIT® RL 100 or EUDRAGIT® RS 100. EUDRAGIT®

RL PO (Type A) and EUDRAGIT® RS PO (Type B) are described in the monographs quoted above.

EUDRAGIT® RL 100 / RL PO and EUDRAGIT® RS 100 / RS PO are copolymers of ethyl

acrylate, methyl methacrylate and a low content of a methacrylic acid ester with quaternary ammonium groups (trimethylammonioethyl methacrylate chloride). The ammonium groups are present as salts and make the polymers permeable. The molar ratio of ethyl acrylate, methyl methacrylate and trimethylammonioethyl methacrylate is approx. 1:2:0.2 in EUDRAGIT RL and approx. 1:2:0.1 in EUDRAGIT RS.