The present invention aims to provide a method for producing, by a simple
method, drug-containing wax matrix granules, particularly drug-containing
wax matrix granules having an average particle diameter of 1 mm or lower,
while avoiding liquid blockage due to the recrystallization of a molten
drug during the period from a melting step to a spray step.
Drug-containing wax matrix granules having at least one wax and at least
one drug are produced by the following steps (i) and (ii): (i) supplying
the at least one drug and the at least one wax to an extruder in which
the temperature of a barrel and the temperature of a die are adjusted to
be higher than the melting point of the at least one wax; and (ii) while
melting and kneading the at least one drug and the at least one wax in
the extruder to give a molten kneaded drug and wax, spraying the molten
kneaded drug and wax into an atmosphere having a temperature lower than
the melting point of the wax from a spray nozzle directly mounted onto a
die provided at a top end of the barrel of the extruder, thereby forming
the mixture into granules.