Therapeutic peptide and protein drugs are chemically and structurally labile compounds, which are administered usually using invasive injection systems. We have developed surface-modified liposomal systems with mucoadhesive polymers such as chitosan and Carbopol for solving this problem. These surface-modified liposomes have been demonstrated to improve the absorption of the drugs as drug carriers in oral and pulmonary administration. In the ocular therapeutics, drug delivery to the posterior part of eyeball, especially to retina, is also carried out through the injection to the eye. We have found that submicron-sized (100 nm) liposomes with optimal formulations are potential drug carriers for targeting the retina with eye drop preparations. Surface modification of liposomes has also been found to be effective in this application. We succeeded to optimize the molecular weight and concentration of PLL (poly-L-lysine-modified liposomes) for realizing the most effective drug delivery to the retina.
Based on the particle design research with pharmaceutical powders, we have reported the novel preparation methods of nano-crystals and orally disintegrating tablets (ODTs). The nano-crystals of poorly water soluble drugs were prepared with PureNano system, which is a bottom up technique, where the drug is dissolved in a solvent and subsequently precipitated by controlled mixing with a non-solvent. Novel preparation methods of ODTs were developed by preparing composite particles with some combinations of disintegrant, filler and other excipients.【References】1) Pharm. Research, 13:896-901 (1996). 2) Adv. Drug Deliv. Reviews, 47:39-54 (2001). 3) J. Control. Rel., 86:235-242 (2003). 4) J. Pharm. and Biopharm., 80:340-346 (2012) 5) J. Pharm. Sci., 102, 1281-1289 (2013) 6) J. Control. Rel., 136:247-253 (2009). 7）Eur. J. Pharm. Biopharm., 83, 364-369 (2013)
- Design of nanoparticles such as liposomes, polymeric nanospheres for effective drug delivery
- Novel drug delivery systems for ophthalmic and pulmonary drug therapy
- Design of novel solid dosage forms such as rapidly disintegrating tablets and films
- Nano drug crystals for improving its dissolution and absorption
- Tanimura S, Tahara K, Takeuchi H. Spray-dried composite particles of erythritol and porous silica for orally disintegrating tablets prepared by direct tableting. Powder Technology. 286:444-450, 2015.
- Onodera R, Tahara K, Takeuchi H. Advanced particle design of liposomes for drug delivery in oral, pulmonary and ocular administration. Drug Delivery System. 30:121-128, 2015.
- Murata M, Tahara K, Takeuchi H. Real-time in vivo imaging of surface-modified liposomes to evaluate their behavior after pulmonary administration. Eur J Pharm Biopharm. 86:115-119, 2014.
- Katsuno E., Tahara K., Takeuchi Y., Takeuchi H., Orally disintegrating tablets prepared by a co-processed mixture of micronized crospovidone and mannitol using a ball mill to improve compactibility and tablet stability, Powder Technology, 241, 60-66, 2013.