Objective:To study the influence of
suspending agents on the relative
bioavailability of Cyclosporine A-loaded HPMCP(HP55)
nanoparticles for oral administration. Methods:
Suspending agents such as Vanzan,HPMC,Carbopol were added into cyclosporine A-loaded HP55 nanoparticles. The suspended nanoparticle formulations and Neoral were administered orally in a dosage of 15 mg/kg to rats. The CyA concentrations in the blood sample were determined by HPLC. Pharmacokinetic parameters were calculated by 3P97. Results: The concentration-time data of these preparations were best fit by two compartment model with a weight of 1/C 2. Compared with the reference Neoral microemulsion, the relative
bioavailability of 2 g/L Carbopol,5 g/L Vanzan,8,5,3 g/L HPMC suspended nanoparticles were 70.2%, 84.3%,90.0%,94.5% and 97.7%, respectively. Their viscosity values were 550, 362, 105, 30 and 15 mPa·s, respectively. Conclusion: With the increase in viscosity, the relative bioavailability of nanoparticle formulations decreased. So, it is important to select the appropriate viscosity of suspending agents in the formulation design.