DRUG-CONTAINING NANOPARTICLE, PROCESS FOR PRODUCING THE SAME AND PARENTERALLY ADMINISTERED PREPARATION FROM THE NANOPARTICLE

To provide an external preparation or injectable preparation that exerts the effect of enabling transdermal or transmucosal in vivo absorption of fat-soluble drugs and water-soluble drugs not having been satisfactorily attained hitherto and that contains a highly absorbable fat-soluble/water-soluble drug, the injectable preparation especially aiming at sustained-release and target effects. In particular, drug-containing nanoparticles (secondary nanoparticles) are provided by causing primary nanoparticles containing a fat-soluble drug or fat-solubilized water-soluble drug to act with a bivalent or trivalent metal salt. Further, drug-containing nanoparticles (tertiary nanoparticles) are provided by first causing primary nanoparticles containing a fat-soluble drug or fat-solubilized water-soluble drug to act with a bivalent or trivalent metal salt to thereby obtain secondary nanoparticles and thereafter causing a monovalent to trivalent basic salt to act on the secondary nanoparticles. Still further, there are provided a process for producing these nanoparticles, and a transdermal or transmucosal external preparation or injectable preparation in which these nanoparticles are contained.