Our speculations should be additionally supported by microscopic observations to prove that, however, similar research were carried out by Varga et al. in which they performed α-TP encapsulation using poly(lactide acid) (PLA) which similarly to PBA-DLA copolymer possess hydrophobic character. In the cited work, PLA NPs with α-TP were obtained via nanoprecipitation method where transmission electron microscopy (TEM) images were recorded showing that α-TP is located in the core of the NPs and on the surface. After the characterization of the α-TP size, encapsulation efficiency (EE%) was assessed based on the calibration curve prepared using UV-VIS spectroscopy (Figure ). Performed studies indicate that by using α-TP concentration of 5 mg/ml we were able to obtain the highest encapsulation efficiency (74 %) whereas in case of 2.5 and 10 mg/ml those value was calculated to be 50 %.