The present invention relates to sustained-release pharmaceutical compositions
for ionic pharmaceutically active substances containing ionic compounds having
opposite charges to those of ionic prostanoic acid derivatives and increasing hydrophobicity
of the active substances. More specifically, the invention relates to sustained-release
pharmaceutical compositions comprising the ionic prostanoic acid derivatives and
the ionic compounds having opposite charges to those of the prostanoic acid derivatives
and increasing hydrophobicity of these derivatives that contain hydrophobic groups
in the molecule thereof.
The pharmaceutical composition of the invention can exhibit excellent sustained
release effect of the ionic prostanoic acid derivatives, irrespective of water
solubility possessed by the ionic prostanoic acid derivatives.
