<P> The earliest SR drugs is associated with a patent in 1938 by Israel Lipowski, who coated pellets which led to coating particles . The science of controlled release developed further with more oral sustained - release products in the late 1940s and early 1950s, the development of controlled release of marine anti-foulants in the 1950s and controlled release fertilizer in the 1970s where sustained and controlled delivery of nutrients following a single application to the soil . Delivery is usually effected by dissolution, degradation or disintegration of an excipient in which the active compound is formulated . Enteric coating and other encapsulation technologies can further modify release profiles . </P> <P> There is no industry standard for these abbreviations, and confusion and misreading have sometimes caused prescribing errors . Clear handwriting is necessary . For some drugs with multiple formulations, putting the meaning in parentheses is advisable . </P> <Table> <Tr> <Th> Abbreviation </Th> <Th> Meaning </Th> <Th> Notes </Th> </Tr> <Tr> <Td> CD </Td> <Td> controlled delivery </Td> <Td> </Td> </Tr> <Tr> <Td> CR </Td> <Td> controlled release </Td> <Td> </Td> </Tr> <Tr> <Td> DR </Td> <Td> delayed release </Td> <Td> </Td> </Tr> <Tr> <Td> ER </Td> <Td> extended release </Td> <Td> </Td> </Tr> <Tr> <Td> IR </Td> <Td> immediate release </Td> <Td> </Td> </Tr> <Tr> <Td> LA </Td> <Td> long - acting </Td> <Td> </Td> </Tr> <Tr> <Td> LAR </Td> <Td> long - acting release </Td> <Td> </Td> </Tr> <Tr> <Td> MR </Td> <Td> modified release </Td> <Td> </Td> </Tr> <Tr> <Td> PR </Td> <Td> prolonged release </Td> <Td> </Td> </Tr> <Tr> <Td> SA </Td> <Td> sustained action </Td> <Td> Ambiguous, can sometimes mean short - acting </Td> </Tr> <Tr> <Td> SR </Td> <Td> sustained release </Td> <Td> </Td> </Tr> <Tr> <Td> TR </Td> <Td> timed release </Td> <Td> </Td> </Tr> <Tr> <Td> XL </Td> <Td> extended release </Td> <Td> </Td> </Tr> <Tr> <Td> XR </Td> <Td> extended release </Td> <Td> </Td> </Tr> <Tr> <Td> XT </Td> <Td> extended release </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Abbreviation </Th> <Th> Meaning </Th> <Th> Notes </Th> </Tr>

Is extended release the same as time release