title: Formulation and optimization of spray-dried amlodipine solid dispersion for enhanced oral absorption.
abstract: OBJECTIVE
  To enhance the oral absorption of photosensitive amlodipine free base, which exhibits a slow dissolution rate and low permeability characteristics, an amorphous solid dispersion system was formulated and characterized.
  
  
  METHODS
  The solid dispersion was prepared by dispersing the amlodipine free base in excess dextrin (1:10 by weight) using a spray-drying technique in the presence of a minimum amount (0.9% w/w) of SLS as an absorption enhancer. The dextrin-based solid dispersion of amlodipine (Amlo-SD) was evaluated in term of formulation, characterization and in vivo absorption study, as well as the spray-drying process was also optimized.
  
  
  CONCLUSIONS
  The Amlo-SD particles were spherical with a smooth surface and an average particle size of 12.9 μm. Amlodipine was dispersed in an amorphous state and its content remained uniform in the Amlo-SD. The physicochemical stability of the Amlo-SD was maintained at room temperature for 6 months and the photostability was considerably improved. The dissolution of the Amlo-SD was much faster than that of amlodipine at pH 1.2 and 6.8. Amlo-SD produced significantly higher plasma concentrations of amlodipine in rats than amlodipine alone. Amlo-SD with and without SLS provided 2.8- and 2.0-fold increase in AUC, respectively: the difference seems to be attributed to a permeability enhancement effect by SLS.
  
  
  CONCLUSIONS
  The Amlo-SD with SLS system is a potential formulation option for amlodipine.
authors.affiliation: College of Pharmacy, The Catholic University of Korea, Bucheon , Gyeonggi, 420-743 , South Korea.
authors.forename: Dong-Jin
authors.initials: DJ
authors.lastname: Jang
authors.forename: Taeyong
authors.initials: T
authors.lastname: Sim
authors.forename: Euichaul
authors.initials: E
authors.lastname: Oh
mesh_terms: D000042:Absorption; D000284:Administration, Oral; D017311:Amlodipine / Q000737:chemistry* / Q000493:pharmacokinetics; D000818:Animals; D018938:Caco-2 Cells; D002121:Calcium Channel Blockers / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D004355:Drug Stability; D006801:Humans; D008297:Male; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D012995:Solubility
chemical_list: D002121:Calcium Channel Blockers; D017311:Amlodipine