title: Utility of 2-hydroxypropyl-beta-cyclodextrin in an intramuscular injectable preparation of nimodipine.
abstract: Possible utility of hydroxyalkylated beta-cyclodextrin (beta-CyD) derivatives as parenteral drug carriers was investigated, using nimodipine, a dihydropyridine derivative with calcium antagonistic action, as a model drug. The aqueous solubility of nimodipine increased linearly with increase in the concentration of hydroxyalkylated beta-CyDs, showing an AL-type phase solubility diagram. The stability constant of nimodipine--hydroxyalkylated beta-CyD complexes was in the order of 2,3-dihydroxypropyl-beta-CyD less than beta-CyD less than 2-hydroxyethyl-beta-CyD less than 3-hydroxypropyl-beta-CyD less than 2-hydroxypropyl-beta-CyD, and the solubilizing ability of the beta-CyDs was also in that order. The results of powder X-ray diffractometry and thermal analysis suggested 1:3 (guest:host) complex formation of nimodipine with 2-hydroxypropyl-beta-CyD in the solid state. The dissolution rate of nimodipine-2-hydroxypropyl-beta-CyD complex was much faster than that of the drug alone. Nimodipine-2-hydroxypropyl-beta-CyD complex gave higher plasma levels of the drug after intramuscular administration to rabbits, i.e., the area under the plasma concentration--time curve and the maximum plasma concentration of the complex were about 2.5 times higher than those of the drug alone. The muscular damage after the injection of nimodipine was reduced by the administration of the complexed form.
authors.affiliation: Faculty of Pharmaceutical Sciences, Kumamoto University, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Itoh
authors.forename: T
authors.initials: T
authors.lastname: Irie
authors.forename: F
authors.initials: F
authors.lastname: Hirayama
authors.forename: K
authors.initials: K
authors.lastname: Uekama
mesh_terms: D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000818:Animals; D003505:Cyclodextrins; D003912:Dextrins; D005079:Excipients; D007273:Injections, Intramuscular; D008297:Male; D009553:Nimodipine / Q000008:administration & dosage*; D011817:Rabbits; D012995:Solubility; D013213:Starch; D047392:beta-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D003912:Dextrins; D005079:Excipients; D047392:beta-Cyclodextrins; D000073738:2-Hydroxypropyl-beta-cyclodextrin; D009553:Nimodipine; D013213:Starch