title: Enhanced solubility and bioavailability of sibutramine base by solid dispersion system with aqueous medium.
abstract: To develop a novel sibutramine base-loaded solid dispersion with improved solubility bioavailability, various solid dispersions were prepared with water, hydroxypropylmethyl cellulose (HPMC), poloxamer and citric acid using spray-drying technique. The effect of HPMC, poloxamer and citric acid on the aqueous solubility of sibutramine was investigated. The physicochemical properties of solid dispersion were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray powder diffraction. The dissolution and pharmacokinetics in rats of solid dispersion were evaluated compared to the sibutramine hydrochloride monohydrate-loaded commercial product (Reductil). The sibutramine base-loaded solid dispersion gave two type forms. Like conventional solid dispersion system, one type appeared as a spherical shape with smooth surface, as the carriers and drug with relatively low melting point were soluble in water and formed it. The other appeared as an irregular form with relatively rough surface. Unlike conventional solid dispersion system, this type changed no crystalline form of drug. Our results suggested that this type was formed by attaching hydrophilic carriers to the surface of drug without crystal change, resulting from changing the hydrophobic drug to hydrophilic form. The sibutramine-loaded solid dispersion at the weight ratio of sibutramine base/HPMC/poloxamer/citric acid of 5/3/3/0.2 gave the maximum drug solubility of about 3 mg/ml. Furthermore, it showed the similar plasma concentration, area under the curve (AUC) and C(max) of parent drug, metabolite I and II to the commercial product, indicating that it might give the similar drug efficacy compared to the sibutramine hydrochloride monohydrate-loaded commercial product in rats. Thus, this solid dispersion system would be useful to deliver poorly water-soluble sibutramine base with enhanced bioavailability.
authors.affiliation: College of Pharmacy, Yeungnam University, 214-1 Dae-dong, Gyongsan 712-749, South Korea.
authors.forename: Dong Xun
authors.initials: DX
authors.lastname: Li
authors.forename: Ki-Young
authors.initials: KY
authors.lastname: Jang
authors.forename: Wonku
authors.initials: W
authors.lastname: Kang
authors.forename: Kyoungjin
authors.initials: K
authors.lastname: Bae
authors.forename: Mann Hyung
authors.initials: MH
authors.lastname: Lee
authors.forename: Yu-Kyoung
authors.initials: YK
authors.lastname: Oh
authors.forename: Jun-Pil
authors.initials: JP
authors.lastname: Jee
authors.forename: Young-Joon
authors.initials: YJ
authors.lastname: Park
authors.forename: Dong Hoon
authors.initials: DH
authors.lastname: Oh
authors.forename: Youn Gee
authors.initials: YG
authors.lastname: Seo
authors.forename: Young Ran
authors.initials: YR
authors.lastname: Kim
authors.forename: Jong Oh
authors.initials: JO
authors.lastname: Kim
authors.forename: Jong Soo
authors.initials: JS
authors.lastname: Woo
authors.forename: Chul Soon
authors.initials: CS
authors.lastname: Yong
authors.forename: Han-Gon
authors.initials: HG
authors.lastname: Choi
mesh_terms: D000818:Animals; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003503:Cyclobutanes / Q000737:chemistry* / Q000493:pharmacokinetics*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D003503:Cyclobutanes; D014867:Water; C058254:sibutramine