Hot Melt

Combination Devices, granules, films, fibers, tubes, complex dosage forms, coextrusion

Recent advances in drug discovery have led to an increase in the number of active pharmaceutical ingredients (APIs) that are poorly water soluble (PWS). These PWS drugs cannot be formulated using traditional methods. Hot melt extrusion is emerging as a leading technology for increasing drug solubility and enhancing bioavailability.

Explanation of Process

Foster Delivery Science’s pharmaceutical hot melt extrusion is performed in a cGMP production facility using twin screw extruders qualified and designed for drug delivery applications. Twin screw extruders are frequently used to prepare solid dispersions due to their high kneading and dispersing capacities, and short transit time. Process design features such as screw design, barrel configuration and feed location can be custom tailored for each formulation.

To facilitate in process formulation development, our engineers characterize each ingredient for thermal and rheological properties. The data is used for initial process design. Our equipment and extruders allow us to work with as little as 30- 50-gram batches of material for proof of concept and early formulation development. 1 of 7

Our feeders are designed to accurately dispense APIs, excipients, and polymers in a wide range of forms, including powders, granules, liquids, or pellets. Ingredients can be individually fed gravimetrically or pre-blended using a turbula mixer, bin, or V-blenders to create batches.

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The feed section of the screws contains wide pitched elements to move the material away from the feed throat of the extruder to prevent the formulation from melting prematurely and bridging. The screws in the twin-screw hot melt extrusion process are self-wiping. 3 of 7 Each hot melt extrusion process has a “process energy”. Process energy is comprised of mechanical and thermal energies that ensure homogenous mixing without degradation of the API or excipients.  Mechanical energy influences the shear forces imparted on the formulation. Thermal energy determines the amount of heat the formulation experiences in the process. 4 of 7 Mixing sections of the process are comprised of dispersive and distributive mixing elements to create uniform content. Thermal energy is derived from the input temperatures, the shear forces and the mechanical energy from the screw elements and shafts. 5 of 7

In the last section of the extruder, material is pumped out of a die. Tighter pitched conveying elements are used to build up pressure to push the material out of the extruder.

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The most common output of HME is in pellet form of varying sizes and shapes. These can be used in downstream shaping processes to create the final products. Our processes can be optimized and scaled on one of several extruders in our development lab or cGMP suites.

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