No difference between SR and ER
Thanks for the query
Your pharmacist was right, there is no difference in ER ( extended release) and SR ( sustain release). It has been used interchangeably. SR is an old terminology as compared to ER which is a newer terminology.
It is just a method of drug delivery system where the drug gets released over a prolonged period of time. There is another term used known as PR ( pulsatile release) which is equal to SR and ER.
So to sum it all up SR=ER=PR.
I hope I was of help, if you have any further queries please get back to me