Novel oral formulation approach for poorly water-soluble drug using lipocalin-type prostaglandin D synthase.

Lipocalin-type prostaglandin D synthase (L-PGDS), a member of the lipocalin superfamily, possesses the function of forming complexes together with various small lipophilic molecules. In this study, we chose telmisartan as a model drug due to its pH dependent poor water solubility, and developed and characterized a novel solubilized formulation of telmisartan using a complex formulation with L-PGDS. The solid state of the complex formulation was prepared using a spray-drying process. The spray-dried formulation of telmisartan/L-PGDS powder showed a typical spray-dried particle without any change in the secondary and tertiary structures of L-PGDS. Furthermore, the complex formulation showed a high rate and level of drug release in pH 1.2, 5.0, and 6.8 solutions in comparison with the active pharmaceutical ingredient (API) and commercial product. To validate the potential for oral administration of the telmisartan/L-PGDS complex in vivo, the pharmacokinetic and pharmacodynamic profiles were assessed in spontaneous hypertensive rats. An animal study revealed that the complex formulation led to a significant improvement of AUC and Cmax as compared with API, and the prolonged pharmacologic effect on blood pressure reduction was comparable with the commercial product. These results, taken together, demonstrate that this novel approach is feasible for the solubilized solid oral formulation and it can be applied to poorly water-soluble drugs to enhance oral bioavailability.