The hydrobromide salt of morphine-6-.beta.-D-glucuronide (M6G.HBr) is surprisingly stable compared to other M6G salts and M6G base. Use of M6G.HBr as a medicament in particular as an analgesic and methods of making M6G.HBr are described.

The invention provides a novel method for synthesising M6G and intermediates therefor. In order to synthesise M6G the major problem to overcome is to obtain the glycoside linkage with very high .beta.-selectivity since prior methods produce the .alpha.-anomer. The invention provides a method for the preferential synthesis of the .beta.-anomer of M6G which includes the step shown in Scheme 6: wherein use of DMAP is optional.

Hydrobromide salt of morphine-6-?-D-glucuronide (M6G.HBr) a medicament and a pharmaceutical composition comprising the M6G.HBr are disclosed. Methods of treating diseases using M6G.HBr use of M6G.HBr as a medicament in particular as an analgesic are provided. Methods of making M6G.HBr and pharmaceutical compositions comprising the M6G.HBr also are provided.

Morphine derivatives of formula (I) process for preparing them and their use as analgesics.

The invention provides a novel method for synthesizing Morphine-6-Glucuronide comprising the step of reacting 3-O-pivaloyloxymorphine and methyl 1&agr;2-ethylorthopivalate-34-di-O-pivaloylglucouronate.

The invention provides a novel method for synthesising M6G and intermediates therefor. In order to synthesise M6G the major problem to overcome is to obtain the glycoside linkage with very high -selectivity since prior methods produce the -anomer. The invention provides a method for the preferential synthesis of the -anomer of M6G which includes the step shown in Scheme 6 wherein use of DMAP is optional.