Solid lipid microparticles: An approach for improving oral bioavailability of aspirin

The objectives of the work were to develop a lipid based delivery system for aspirin and to evaluate its physicochemical and pharmacodynamic properties. Aspirin-loaded solid lipid microparticles (SLMs) were formulated by hot homogenization and analysed for their encapsulation efficiency (EE%), in vitro release, particle size, anti-inflammatory and ulcer inhibition properties. Particle size ranged from 33.10 ± 5.85 to 43.50 ± 7.27 µm for batches A1 to A3 SLMs loaded with 1, 3 and 5% aspirin and containing Poloxamer 407, while batches B1, B2 and B3 formulated with Soluplus as surfactant had particle size range of 31.10 ± 1.46 to 45.60 ± 2.92 µm. Batches A1 and B1 containing 1% of aspirin had the highest EE of 70 and 72% respectively. Maximum in vitro release of 95.1 and 93.2% were obtained at 8 h from batches A1 and B1 respectively. SLMs exhibited about 77.8% oedema inhibition, while the reference had 66.7% and ulcer inhibition range of 25–75%. Aspirin-loaded SLMs exhibited good properties and could be used orally twice daily for the treatment of inflammation.