[Effects of sperminated pullulans on the pulmonary absorption of insulin]

Strategies to Enhance Drug Absorption via Nasal and Pulmonary Routes

New therapeutic agents such as proteins, peptides, and nucleic acid-based agents are being developed every year, making it vital to find a non-invasive route such as nasal or pulmonary for their administration. However, a major concern for some of these newly developed therapeutic agents is their poor absorption. Therefore, absorption enhancers have been investigated to address this major administration problem. This paper describes the basic concepts of transmucosal administration of drugs, and in particular the use of the pulmonary or nasal routes for administration of drugs with poor absorption. Strategies for the exploitation of absorption enhancers for the improvement of pulmonary or nasal administration are discussed, including use of surfactants, cyclodextrins, protease inhibitors, and tight junction modulators, as well as application of carriers such as liposomes and nanoparticles.

The effects of sperminated pullulans on cornea permeability to puerarin and the toxicity

PURPOSE

To investigate the varied effects of sperminated pullulans (SP) with different amino residues on cornea permeability and its local toxicity.

METHODS

Three groups of rabbits were used: control, low-amino residue content SP (SP-L), and high-amino residue content SP (SP-H). The in vitro and in vivo spreading assays were combined with high performance liquid chromatography (HPLC) to measure the concentration of puerarin in the external medium or aqueous humor when 0% SP, 0.2% SP-L, and 0.2% SP-H were included. The toxicity of SP was determined by corneal hydration values, Draize score, aqueous humor protein concentration, corneal endothelial evaluation, as well as light microscopy and electron microscopy.

RESULTS

The application of 0.2% SP-L and 0.2% SP-H to the cornea in vitro increased puerarin apparent permeability coefficient by 1.96-fold (P<0.05) and 2.95-fold (P<0.01), respectively. SP-H showed stronger effect than SP-L (P<0.05). For the in vivo assay, those were 1.81-fold (P<0.05) and 3.71-fold (P<0.01), respectively. With the SP application, the corneal hydration values were <83% and Draize scores were <4, with no apparent changes in histological observations.

CONCLUSION

SP is one potential adjuvant promoting puerarin permeability to the cornea, and the high-content amino residue SP showed stronger effect, without ocular toxicity.