Influence of swelling degree on release of nicardipine hydrochloride from acrylic microspheres prepared by solvent evaporation method

YÜKSEL N., DİNÇ E., ONUR F., Baykara T.

Pharmaceutical Development and Technology, vol.3, no.1, pp.115-121, 1998 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 3 Issue: 1
  • Publication Date: 1998
  • Doi Number: 10.3109/10837459809028485
  • Journal Name: Pharmaceutical Development and Technology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.115-121
  • Keywords: Controlled release, Enteric dosage form, Eudragit RS-L mixture, Nicardipine polymeric microspheres, Solvent evaporation, Swelling degree
  • Lokman Hekim University Affiliated: Yes


The purpose of this study was to prepare and evaluate an enteric coated dosage form of nicardipine hydrochloride (NCH)-loaded microspheres for delivery over a 12-hr period. Microspheres containing Eudragit RS and L with different ratios were prepared by solvent evaporation method and the effect of swelling on the release rate and characteristics was investigated. The change in the diameters of microspheres with time in simulated intestinal fluid (pH 7.5) at 37°C has been studied. Drug release was determined using the flow-through cell method, and related to the degree of swelling (Q) of the microspheres. Q values in turn depended on the ratio of Eudragit RS-L used. Release of NCH from microspheres increased with Eudragit L amount, but no controlled-release pattern was observed. Q values ≤18.88 caused a slow initial release followed by an accelerated release. Microspheres with an Eudragit RS-L ratio of 1:5.7, Q value of 38.71, and drug release rate of 0.155% min11 exhibited a remarkable delayed time for erosion to begin (120 min). Thus, microspheres prepared from this formulation may provide an effective enteric dosage form, releasing NCH at a predetermined rate.