In nasal drug product development, biorelevant in vitro methodologies are vital in order to select promising compounds or formulations, potentially reducing pre-clinical and clinical trials. Permeability assays are often applied to predict drug absorption and bioavailability. For nasal delivery products, permeation models include ex vivo models using excised nasal mucosa and in vitro cell culture models. However, ex vivo models present high variability and cell culture models are very time consuming. The Parallel Artificial Membrane Permeability Assay (PAMPA) has emerged as a high throughput screening tool to evaluate drug permeability, and it has been applied to several barriers such as the intestine, skin or blood-brain-barrier. Herein, a new PAMPA model was developed and optimized to predict nasal permeability, using a biorelevant donor medium containing mucin. The apparent permeability (Papp) of 15 reference compounds was assessed in six different experimental conditions. The model with 0.5% (w/v) mucin in the donor compartment and 2% (w/v) phosphatidylcholine in the lipid membrane correctly distinguished high and low permeable compounds, with no false positives or negatives. In addition, it exhibited the highest correlation with permeation across human nasal epithelial RPMI 2650 cells (R2 = 0.71). Overall, the optimized PAMPA model was reproducible, predictive and inexpensive, showing to be a promising non-cell based and biorelevant in vitro tool that could be applied in an early screening stages of new nasal drug delivery products.
Raquel Borda D’Água, Associate Analytical Scientist, R&D Analytical Development
João Pereira, Manager R&D Analytical Development
Dry powder inhalers (DPIs) have attracted enormous attention worldwide due to its local targeting, rapid drug effect and reduced systemic toxicity. However, DPI formulations consist of highly cohesive powders that tend to agglomerate. Therefore, understanding the role of cohesive-adhesive forces in different formulations and establishing a predictive approach for aerodynamic particle size distribution (aPSD) is thus, highly beneficial. The purpose of this study is to explore the relationship between powder dispersibility with the aerodynamic performance of different DPI formulations. Sympatec was used to characterise powder dispersibility and inherent cohesion and adhesion forces at different pressures. Powder dispersibility obtained by Sympatec and aerodynamic properties from the NGI analysis were evaluated in order to deeper understand the characteristic behaviour of these formulations