Effects of Particle Size, Helium Gas Pressure and Microparticle Dose on the Plasma Concentration of Indomethacin after Bombardment of Indomethacin-Loaded Poly-L-Lactic Acid Microspheres Using a HeliosTM Gun System
Biological and Pharmaceutical Bulletin
We investigated the effects of the particle size of indomethacin-loaded poly-L-lactic acid microspheres (IDMloaded PLA MS), the helium pressure used to accelerate the particles, and the bombardment dose of PLA MS on the plasma concentration of IDM after bombarding with IDM-loaded PLA MS of different particle size ranges, 20-38, 44-53 and 75-100 m mm, the abdomen of hairless rats using the Helios TM gene gun system (Helios TM gun system). Using larger particles and a higher helium pressure,
... lium pressure, produced an increase in the plasma IDM concentration and the area under the plasma concentration-time curve (AUC) and resultant F (relative bioavailability with respect to intracutaneous injection) of IDM increased by an amount depending on the particle size and helium pressure. Although a reduction in the bombardment dose led to a decrease in C max and AUC, F increased on decreasing the bombardment dose. In addition, a more efficient F was obtained after bombarding with IDMloaded PLA MS of 75-100 m mm in diameter at each low dose in different sites of the abdomen compared with that after bolus bombardment with a high dose (dose equivalent). These results suggest that the bombardment injection of drug-loaded microspheres by the Helios TM gun system is a very useful tool for delivering a variety of drugs in powder form into the skin and systemic circulation.