Lowering heat stresses on API by reducing friction
Without friction, we would not be able to walk, jot down notes, or slice a pie. Friction resists the relative motion of two objects that come in contact, generating grip between their surfaces.
But if you’re drying high-potency API, friction is the last thing you need. The force exerts mechanical and thermal stress on the ingredients that could destabilize the materials and compromise the quality of your end product.
A poor work of friction
High-potency active pharmaceutical ingredients (API) require thorough drying to ensure homogeneity in the production process. Once crystallized and isolated from organic solvents, the ingredients must be prepared into free-flowing materials ready for precision dosing, formulating, and formatting.
The drying step is a delicate process that converts the particles into workable materials without altering the chemical profiles developed during filtration. Vacuum drying is a cornerstone of this production stage. The method removes a high rate of bound moisture from materials at relatively low temperatures.
But the vacuum method solves one challenge and creates another. The agitator inside the drum spreads the ingredients over a broader area to expose trapped moisture to vaporization. Therefore, the blades on the agitator make direct contact with the surface of the HPAPI particles. This process creates friction at a millimetric level, producing heat.
No one wants burnt pizza. Or overheated API
Dario Penco, a technical engineer at Italvacuum, says that adding thermal energy during the drying stage is similar to overcooking: “The effects of friction while drying sensitive materials is like pulling a perfectly-baked pizza out of the oven and placing it over a blazing cooktop.”
The emergence of high-potency drugs has made this challenge even more pressing. The slightest distortions in the composition of the particles create a ripple effect across the manufacturing line.
Production engineering is developing new ways to overcome this hurdle and minimize friction occurring in a vacuum dryer. Novel design approaches to the blade profile reduce the physical contact with the materials and limit thermal stress significantly. Keeping temperatures at a constant ensures higher-quality pharmaceutical ingredients. And just like well-baked pizza, everyone wants a slice of that.