title: Improving the dissolution rate of poorly water soluble drug by solid dispersion and solid solution: pros and cons.
abstract: The solid dispersions with poloxamer 188 (P188) and solid solutions with polyvinylpyrrolidone K30 (PVPK30) were evaluated and compared in an effort to improve aqueous solubility and bioavailability of a model hydrophobic drug. All preparations were characterized by differential scanning calorimetry, powder X-ray diffraction, intrinsic dissolution rates, and contact angle measurements. Accelerated stability studies also were conducted to determine the effects of aging on the stability of various formulations. The selected solid dispersion and solid solution formulations were further evaluated in beagle dogs for in vivo testing. Solid dispersions were characterized to show that the drug retains its crystallinity and forms a two-phase system. Solid solutions were characterized to be an amorphous monophasic system with transition of crystalline drug to amorphous state. The evaluation of the intrinsic dissolution rates of various preparations indicated that the solid solutions have higher initial dissolution rates compared with solid dispersions. However, after storage at accelerated conditions, the dissolution rates of solid solutions were lower due to partial reversion to crystalline form. The drug in solid dispersion showed better bioavailability in comparison to solid solution. Therefore, considering physical stability and in vivo study results, the solid dispersion was the most suitable choice to improve dissolution rates and hence the bioavailability of the poorly water soluble drug.
authors.affiliation: Applied Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Rina J
authors.initials: RJ
authors.lastname: Chokshi
authors.forename: Hossein
authors.initials: H
authors.lastname: Zia
authors.forename: Harpreet K
authors.initials: HK
authors.lastname: Sandhu
authors.forename: Navnit H
authors.initials: NH
authors.lastname: Shah
authors.forename: Waseem A
authors.initials: WA
authors.lastname: Malick
mesh_terms: D000818:Animals; D001682:Biological Availability; D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D004285:Dogs; D004355:Drug Stability; D007700:Kinetics; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D019999:Pharmaceutical Solutions; D020442:Poloxamer / Q000737:chemistry; D011205:Povidone / Q000737:chemistry; D012995:Solubility; D012997:Solvents; D013501:Surface-Active Agents; D014867:Water; D014961:X-Ray Diffraction
chemical_list: D004364:Pharmaceutical Preparations; D019999:Pharmaceutical Solutions; D012997:Solvents; D013501:Surface-Active Agents; D014867:Water; D020442:Poloxamer; D011205:Povidone