Enteric micro-particles for targeted oral drug delivery

AAPS PharmSciTech. 2010 Dec;11(4):1500-7. doi: 10.1208/s12249-010-9528-3. Epub 2010 Oct 8.

Abstract

This work is focused on production of enteric-coated micro-particles for oral administration, using a water-in-oil-in-water solvent evaporation technique. The active agent theophylline was first encapsulated in cellulose acetate phthalate (CAP), a pH-sensitive well-known polymer, which is insoluble in acid media but dissolves at neutral pH (above pH 6). In this first step, CAP was chosen with the aim optimizing the preparation and characterization methods. The desired release pattern has been obtained (low release at low pH, higher release at neutral pH) but in presence of a low encapsulation efficiency. Then, the CAP was replaced by a novel-synthesized pH-sensitive poly(methyl methacrylate-acrylic acid) copolymer, poly(MMA-AA). In this second step, the role of two process parameters was investigated, i.e., the percentage of emulsion stabilizer (polyvinyl alcohol, PVA) and the stirring power for the double emulsion on the encapsulation efficiency. The encapsulation efficiency was found to increase with PVA percentage and to decrease with the stirring power. By increasing the PVA content and by decreasing the stirring power, a high stable double emulsion was obtained, and this explains the increase in encapsulation efficiency found.

MeSH terms

  • Administration, Oral
  • Bronchodilator Agents / administration & dosage*
  • Bronchodilator Agents / pharmacokinetics
  • Capsules*
  • Cellulose / analogs & derivatives*
  • Cellulose / chemistry
  • Delayed-Action Preparations
  • Drug Compounding
  • Drug Delivery Systems*
  • Emulsions / chemistry
  • Excipients / chemistry
  • Hydrogen-Ion Concentration
  • Microspheres
  • Polymethacrylic Acids / chemistry*
  • Polyvinyl Alcohol / chemistry*
  • Solubility
  • Theophylline / administration & dosage*
  • Theophylline / pharmacokinetics

Substances

  • Bronchodilator Agents
  • Capsules
  • Delayed-Action Preparations
  • Emulsions
  • Excipients
  • Polymethacrylic Acids
  • Polyvinyl Alcohol
  • Cellulose
  • cellulose acetate phthalate
  • Theophylline