*1.4.3 Hot melt extrusion*

Extrusion is a helpful technique for producing co-crystals because it involves improved surface contacts and highly effective mixing without the need for solvent. The compound's thermodynamic stability is the main factor that determines whether this method should be used. Four co-crystal formation models were used to study this method. Utilizing the solvent drop extrusion technique, the process was optimized and made more adaptable. The benefit of using the solvent drop extrusion technique is the ability to run the process at a lower temperature. The synthesis of carbamazepine-nicotinamide co-crystals with polymer as former was done using the hot melt extrusion method. Co-former, API and continuous co-crystallization were poured into the twin extruder. The temperature of the barrel also rises as a result of the mixture being added continuously [57].
