title: Modified drug release of poloxamer matrix by including water-soluble and water-insoluble polymer.
abstract: BACKGROUND
  The ability of poloxamer 407 to control drug release was investigated along with the effect of incorporation of a second polymer with poloxamer on dissolution behavior.
  
  
  METHODS
  Tablets made of 30% w/w/ theophylline and 15%, 25%, 50%, or 69% poloxamer were prepared. Additionally, tablets containing mixture of poloxamer with carbomer or hypromellose in a 1:1 ratio and at different total levels (15%, 30%, and 50%) were also tested.
  
  
  RESULTS
  Data show that as the level of poloxamer increased, drug release decreased. Formulations containing poloxamer: hypromellose 1:1 at 50% level and formulations containing poloxamer: carbomer 1:1 at 30% level produced controlled release matrices over 24 hours of testing dissolution. The mechanism of drug release follows anomalous relaxation non-Fickian diffusion model.
  
  
  CONCLUSIONS
  These results suggest that the combination of poloxamer 407 with hypromellose or carbomer is feasible and has potential to offer the formulator control over drug release.
authors.affiliation: School of Pharmacy, Medical Sciences Campus, University of Puerto Rico, San Juan, Puerto Rico 00936-5067.
authors.forename: Y M
authors.initials: YM
authors.lastname: Gonzalez
authors.forename: E S
authors.initials: ES
authors.lastname: Ghaly
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D003692:Delayed-Action Preparations; D004058:Diffusion; D016503:Drug Delivery Systems; D005079:Excipients / Q000737:chemistry*; D005240:Feasibility Studies; D065347:Hypromellose Derivatives; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D020442:Poloxamer / Q000737:chemistry*; D012995:Solubility; D013607:Tablets; D013806:Theophylline / Q000008:administration & dosage* / Q000737:chemistry; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D005079:Excipients; D013607:Tablets; C479038:carbomer; D014867:Water; D020442:Poloxamer; D065347:Hypromellose Derivatives; D008747:Methylcellulose; D013806:Theophylline