Magnetic manotheranostics can be a fascinating charm to diagnose a tumour with MRI, and treatment through hyperthermia. This study aims to synthesise and characterise magnetically responsive polymer colloids (MRPCs). Healthy tissue damage done by chemotherapy session could be minimised by MRPCs. For the colloidal formulation of MRPCs, the oil in water emulsion technique was employed with the aid of sonication and stirring. The organic phase of emulsion contained methotrexate (MTX) drug, Eudragit E100 and CoFe2O4 (synthesised by co-precipitation) in ethanol, and the aqueous phase contained tween 80 in deionised water. The emulsion was optimised by studying/adjusting two different parameters, i.e. the concentration of constituents and sonication cycles. Multiple formulations were produced at sonication amplitude of 60% at 20 kHz, followed by centrifugation and lyophilisation. Characterisation of MRPCs was done for morphology, size measurement (23-25 nm), surface charge (∼15.12), coercivity (∼1549.6 G), magnetisation (2.6 emu) and retentivity (1.34 emu). Drug release in simulating physiological environment (pH = 7.4), was observed for up to 48 h, and, to determine the best release kinetic mechanism results were compared with kinetic models. Magnetic hyperthermia studies showed that MRPCs achieved an acceptable temperature of 42°C, for hyperthermia treatments in cancer patients.