In vitro and in vivo evaluation of levofloxacin sustained-release capsules

Objective: To reduce the frequency of administration and improve patient compliance, novel levofloxacin sustained-release capsules with suitable in vitro release profiles and good bioavailability were developed. Materials and methods: A fluidized bed was used to prepare levofloxacin pellets by spraying the drug solution onto blank pellets. Then the pellets were coated with either Surelease water dispersion or Eudragit (R) NE30D water dispersion to achieve sustained-release characteristics. The mixed pellets containing 15% of the uncoated pellets and 85% of the coated pellets were filled into the hard gelatin capsules. In vitro release test was performed with the capsules. A single-dose pharmacokinetic study of the capsules was carried out in beagle dogs. Results: Although Eudragit (R) NE30D-coated pellets and Surelease-coated pellets showed similar sustained-release profiles in vitro, their in vivo pharmacokinetic characteristics exhibited significant difference. Unsuccessful in vivo-in vitro correlation was shown in Eudragit (R) NE30D-coated pellets with a relative bioavailability of only 41.5%, whereas Surelease-coated pellets achieved best sustained-release feature both in vitro and in vivo with a relative bioavailability of 103.0%. Conclusion: Statistical analysis indicated that the capsules containing Surelease-coated pellets had a satisfactory sustained-release behavior and a desired pharmacokinetic property.