Production and characterization of testosterone undecanoate-loaded NLC for oral bioavailability enhancement

Purpose: Nanostructured lipid carriers were loaded with testosterone undecanoate (TU), which has a low oral bioavailability. Methods: Different NLC dispersions were produced using the hot high pressure homogenization method. Particles were characterized using dynamic and static light scattering techniques, differential scanning calorimetry and X-ray diffraction. And the bioavailability was compared to a marketed product. Results: Nanostructured lipid carriers with up to 30% TU load and sizes of about 600 and 200 nm could be achieved, allowing a direct comparison of the size effect in in vivo bioavailability studies. The zeta potentials varied between -20 and -40 mV. The bioavailability of Andriol Testocaps (R) in the fed state was matched. Conclusions: This opens the perspective of administering a single dose of dose of TU in one oral dosage unit and simultaneously having a bioavailability less dependent on the fed state.