DEVELOPMENT OF AN INTRANASAL FORMULATION OF THE Y2R AGONIST PEPTIDE YY3-36.
Peptide YY (PYY) was identified in the 1980s as a hormone produced in the gut and as early as 1993 it was demonstrated that peripheral administration of PYY was a satiety factor in mammals and could thus be a potential treatment for obesity. Subsequent research has identified that PYY is released in proportion to the calorie content of a meal. When administered peripherally to humans at a dose of 20 ug, PYY3-36, the 34 amino acid C-terminal fraction of PYY, reduces caloric intake by approximately 30% in both lean and obese subjects over the 24 hour period following the infusion. Preclinical and clinical studies conducted to date have used injection (IV, ICV or IP) as the method of delivery of PYY3-36. For long term therapy, however, chronic injection may present a challenge for patient compliance, particularly in an injection-naïve patient population. A nasal drug delivery system which can offer adequate bioavailability for a 4 kD peptide such as PYY3-36 would enable routine dosage without the limitations of injections. Advantages of Nasal Formulation: Nasal administration offers a number of potential advantages over oral, pulmonary, or injection drug delivery methods: • Rapid onset: 5-15 minute Tmax • Control of PK via dosing schedule • No 1st pass metabolism • No pulmonary toxicity • No peptide degradation by gastric acid • Non-invasive compared to injections Use of EpiAirway: (selected excerpts) In order to further optimize stability, Nastech Pharmaceuticals and UCLA scientists tested various stabilizing agents for their ability to facilitate passage of drug across the nasal mucosa. The enhancers tested were chosen based on their ability to open tight junctions with limited cellular toxicity. To accomplish this, a primary human epithelial cell model (EpiAirway, MatTek, Inc., Ashland MA) was employed. This cell line forms a pseudo-stratified columnar epithelial cell layer with tight junctions similar to the respiratory epithelium found in the nose. Drug formulations were placed on the apical side of the tissue layer, and drug quantitation carried out for the basal media. The extent of tight junction opening was measured by decrease in the transepithelial electrical resistance (TEER). Cell viability and cytotoxicity were monitored by MTT and LDH assays, respectively. There was a substantial decrease in TEER for several formulations tested, indicating tight junction opening. The decrease in TEER has been shown to correlate with the permeation of drug across the cell layer. In the toxicity assays, two of the candidate formulations exhibited decreased cell viability by the MTT assay and increased cell cytotoxicity by the LDH assay. These data demonstrate the capability of the (EpiAirway) in vitro cell model to differentiate formulations with varying degrees of toxicity. In total, over 200 different formulations were tested, reflecting the high-throughput nature of the in vitro screening model (EpiAirway). Using all the available data, a multivariate analysis was conducted to elucidate the effect each formulation component exerted on each of the 7 output variables (drug permeability, osmolality, stability at refrigerated and accelerated conditions, TEER, and MTT and LDH assays). Based on these analyses, an optimized PYY3-36 formulation was selected for further development.
Dosing schedule, Drug Optimization, Drug permeation, EpiAirway, Formulation, In Vitro formulation screening, Intranasal formulation, LDH assay, Lead Optimization, MTT, MTT ET-50 tissue viability assay, MTT assay, Nasal Mucosa, Nasal drug delivery system, Nasal formulation, Obesity, Osmolality, Peptide, Peptide YY (PYY), Permeation, Pharmacokinetic, Satiety factor, Toxicity testing, Transepithelial electrical resistance (TEER), Transmembrane permeability
Request a copy of this paper, click here.