Improvement of the oral bioavailability of coenzyme Q10 with lecithin nanocapsules.

Coenzyme Q10-loaded lecithin nanocapsules (CoQ10-LNCs), composed of a CoQ10/lecithin/ GTCC/glycerol aqueous solution, were prepared by high-pressure homogenization. The zeta potential of the CoQ10-LNCs above -60 mV was determined on a Malvern Zetasize 2000 (Malvern Instruments, UK). The spherical shape of the CoQ10-LNCs was observed by using freeze-fracture transmission electron microscopy (FF-TEM), and the particle size was found to be below 100 nm. The supercooled state of the CoQ10-LNCs was observed by differential scanning calorimetry (DSC). In an oral bioavailability study, the CoQ10 plasma level after administering CoQ10-LNCs was higher than that after administering a CoQ10 tablet over 24 hours, and the relative bioavailability of CoQ10 was improved to 176.6% in mice. Based on the above results, the LNC delivery system might be a potential vehicle for improving the oral bioavailability of CoQ10.

Preliminary evaluation of a novel oral delivery system for rhPTH1-34: in vitro and in vivo.

rhPTH1-34 is clinically used for osteoporosis treatment. However, this peptide drug has no oral bioavailability because of proteolysis and low membrane permeability in gastrointestinal gut. This study explored the possibility of absorption enhancement for rhPTH1-34 through the oral delivery of the microemulsion. The microemulsion (85:15, oil/water) consisting of Labrasol, Crodamol GTCC, Solutol HS 15, d-α-tocopheryl acetate (6:2:1:1, w/w) and saline water was developed and characterized, including particle size, morphology, drug loading efficiency and permeability, stability and pharmacokinetics. The microemulsion showed high drug loading efficiency (83%) and permeability, and significantly higher resistance to proteolysis in vitro study. The relative oral bioavailability was 5.4% and 12.0% when delivered to gastric and ileum. Besides, osteoporosis rats were induced and treated with oral rhPTH1-34 microemulsion (0.05 mg/kg), injection (0.01 mg/kg) and vehicle, respectively, for 8 weeks. The proximal tibia bone mineral content and density in oral rats (0.188 ± 0.008 g, 0.283 ± 0.014 g/cm(2)) was significantly increased compared to the control rats (0.169 ± 0.006 g, 0.266 ± 0.011 g/cm(2)), reaching to the sham rats. And the proximal tibia microstructure of oral rats was improved greatly, approaching sham level too. These findings revealed that oral microemulsion may represent an effective oral delivery system for rhPTH1-34.