title: Hydrotropic solubilization of paclitaxel: analysis of chemical structures for hydrotropic property.
abstract: OBJECTIVE
  To identify hydrotropic agents that can increase aqueous paclitaxel (PTX) solubility and to study the chemical structures necessary for hydrotropic properties so that polymeric hydrotropic agents can be synthesized.
  
  
  METHODS
  More than 60 candidate hydrotropic agents (or hydrotropes) were tested for their ability to increase the aqueous PTX solubility. A number of nicotinamide analogues were synthesized based on the observation that nicotinamide showed a favorable hydrotropic property. The identified hydrotropes for PTX were used to examine the structure-activity relationship.
  
  
  RESULTS
  N,N-Diethylnicotinamide (NNDENA) was found to be the most effective hydrotropic agent for PTX. The aqueous PTX solubility was 39 mg/ml and 512 mg/ml at NNDENA concentrations of 3.5 M and 5.95 M, respectively. These values are 5-6 orders of magnitude greater than the intrinsic solubility of 0.30 +/- 0.02 microg/ml. N-Picolylnicotinamide, N-allylnicotinamide, and sodium salicylate were also excellent hydrotropes for PTX. Solubility data showed that an effective hydrotropic agent should be highly water soluble while maintaining a hydrophobic segment.
  
  
  CONCLUSIONS
  The present study identified several hydrotropic agents effective for increasing aqueous solubility of PTX and analyzed the structural requirements for this hydrotropic property. This information can be used to find other hydrotropic compounds and to synthesize polymeric hydrotropes that are effective for PTX and other poorly water-soluble drugs.
authors.affiliation: Department of Pharmaceutics and Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Jaehwi
authors.initials: J
authors.lastname: Lee
authors.forename: Sang Cheon
authors.initials: SC
authors.lastname: Lee
authors.forename: Ghanashyam
authors.initials: G
authors.lastname: Acharya
authors.forename: Ching-jer
authors.initials: CJ
authors.lastname: Chang
authors.forename: Kinam
authors.initials: K
authors.lastname: Park
mesh_terms: D004337:Drug Carriers / Q000737:chemistry / Q000378:metabolism; D015394:Molecular Structure; D017239:Paclitaxel / Q000737:chemistry* / Q000378:metabolism*; D012995:Solubility / Q000187:drug effects
chemical_list: D004337:Drug Carriers; D017239:Paclitaxel