The present invention relates to: a compound selected from the group consisting of a tricyclic compound having the structure of formula I, a pharmaceutically acceptable salt, an isomer, a solvate and a precursor thereof; and a use thereof. The compound effectively controls GPR40, and thus, can be effectively used for the prophylaxis or treatment of diseases associated with GPR40, for example, diabetes and many other diseases.

A P2X.sub.4 receptor antagonist such as paroxetine, a diazepinedione derivative having the following formula (IX) is used as an agent for preventing or treating zoster-associated pain in acute phase: ##STR00001##
wherein R.sup.1 is hydrogen, a C.sub.1-8 alkyl group, or the like; each of R.sup.2 and R.sup.3 is hydrogen, a C.sub.1-8 alkyl group, or the like; each of R.sup.4 and R.sup.5 is hydrogen or the like; and W is a five-membered or six-membered heterocyclic ring optionally having one or more substituents and comprising one to four nitrogen atoms as the members of the ring.

A P2X.sub.4 receptor antagonist such as paroxetine, a diazepinedione derivative having the following formula (IX) is used as an agent for preventing or treating zoster-associated pain in acute phase: ##STR00001##
wherein R.sup.1 is hydrogen, a C.sub.1-8 alkyl group, or the like; each of R.sup.2 and R.sup.3 is hydrogen, a C.sub.1-8 alkyl group, or the like; each of R.sup.4 and R.sup.5 is hydrogen or the like; and W is a five-membered or six-membered heterocyclic ring optionally having one or more substituents and comprising one to four nitrogen atoms as the members of the ring.

The present invention provides a process for the synthesis of olopatadine. Further, the invention discloses a process that results in improved yield of the desired Z isomer.

The present invention provides a process for the synthesis of olopatadine. Further, the invention discloses a process that results in improved yield of the desired Z isomer.