Solid lipid nanoparticles for pulmonary delivery of insulin.

Precipitation of Proteins in Supercritical Carbon Dioxide

Effect of surface morphology of carrier lactose on dry powder inhalation property of pranlukast hydrate

The effects of surface morphology of carrier lactose on dry powder inhalation (DPI) property of pranlukast hydrate (PH) were investigated. The PH was mixed with 9-fold weights of carrier lactose, i.e. pharmatose 325M, 200M, DCL-11, DCL-21, spray dried amorphous (SDGa), -crystallized (SDGc) lactoses and fluidized bed granulated lactose (FBG) with various surface morphologies. These mixed powders were aerosolized by a Spinhaler® and in vitro deposition properties were evaluated by a twin impinger. Carrier lactose with higher specific surface area, i.e. surface roughness, like FBG emitted effectively PH particles from the inhalation device, whereas they reduced the respirable fraction captured in the twin impinger, resulting in lower inhalation efficiency, due to strong adhesion of PH to the carrier lactose. The SDGc having lots of microscopical projection on the surface increased the respirable particle percent of the emitted particles, improving the inhalation efficiency. The SDGa, smoothed sphere particle, did not so improve the inhalation efficiency as expected, owing to fairly strong adhesion between PH and lactose particles. Those finding indicated that the separation of drug particles from carrier lactose was a determining step to improve inhalation process for DPIs, as far as lactose particles emitted satisfactorily PH particles from the inhalation device. The surface morphology designed like SDGc, having fairly large surface area with microscopically increased surface roughness was desirable to improve inhalation property of DPI.

Effect of Surface Morphology of Carrier Lactose on Dry Powder Inhalation Property of Pranlukast Hydrate.

Drug delivery to the pulmonary system has been achieved by encapsulation of the drug to be delivered in microparticles having a size range between 0.5 and ten microns, preferably in the range of two to five microns, formed of a material releasing drug at a pH of greater than 6.4. In a preferred embodiment, the drug delivery system is based on the formation of diketopiperazine microparticles which are stable at a pH of 6.4 or less and unstable at pH of greater than 6.4, or which are stable at both acidic and basic pH, but which are unstable at pH between about 6.4 and 8. Other types of materials can also be used, including biodegradable natural and synthetic polymers, such as proteins, polymers of mixed amino acids (proteinoids), alginate, and poly(hydroxy acids). In another embodiment, the microparticles have been modified to effect targeting to specific cell types and to effect release only after reaching the targeted cells.

Pramod K. Gupta

Papers

Contemporary approaches in aerosolized drug delivery to the lung