Four different compositions of polylactide/thermoplastic starch blends (PLA/TPS blends) for application as drug carriers were examined. Initially, using cyanocobalamin (1.355 kDa) as a model compound, the blend with the highest starch content (wt. 60%) was selected for further research of mass transfer phenomenon. In this case, different concentrations of acetaminophen (0.151 kDa), doxorubicin hydrochloride (0.580 kDa) and cyanocobalamin (1.355 kDa) were used for determination of particular releasing profiles. Besides from the comparative analysis of obtained results, the values of the overall mass transfer coefficient (K) were calculated for each of tested drug molecules. Depending on the size and properties of used compound, determined values of the coefficient range from 10−11 to 10−13 m/s. Based on these outcomes, it could be stated that PLA/TPS blend selected in preliminary research, seems to be preferred material for fabrication of long-term drug delivery systems, which could be successfully applied for example in anti-cancer therapy.