Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2506489 | International Journal of Pharmaceutics | 2006 | 6 Pages |
The aim of the current research project was to explore the possibilities of combining pressurized carbon dioxide with hot stage extrusion during manufacturing of solid dispersions of the thermally labile p-aminosalicylic acid (p-ASA) and ethylcellulose 20 cps (EC 20 cps) and to evaluate the ability of the pressurized gas to act as a temporary plasticizer. The thermal stability of the p-ASA was investigated using DSC, TGA and HPLC. The compound decomposes completely upon melting. Below 110 °C and under atmospheric conditions, the compound is thermally stabile for 10 min.Pressurized carbon dioxide was injected into a Leistritz Micro 18 intermeshing co-rotating twin-screw melt extruder using an ISCO 260D syringe pump. Carbon dioxide acted as plasticizer for p-ASA/EC 20 cps, reducing the processing temperature during the hot stage extrusion process. HPLC showed that without carbon dioxide injection, approximately 17% of p-ASA degraded, while less than 5% degraded with CO2 injection. The experiments clearly showed that injecting pressurized carbon dioxide broadens the application of hot stage extrusion to thermally labile compounds in a one step process.