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Non-fluorous triblock copolymers of poly(L-lactide)-block-hydroxypropyl-terminated poly(dimethyl siloxanes)-blockpoly(L-lactide) (PLLA-HTPDMS-PLLA) with two different molecular weights in the range of 4800 to 6500 Da, were prepared by changing the ratio of HTPDMS to L-lactide (L-LA), and were used as stabilizers for the ring-opening dispersion polymerization (RODP) of L-LA to prepare poly(L-lactide) (PLLA) in supercritical carbon dioxide (ScCO2). The experimental results showed that the prepared non-fluorous triblock copolymers were very effective as new stabilizers for the RODP and fine powders of PLLA were obtained. The structure of the stabilizers and PLLA were characterized by ¹H NMR and FTIR spectroscopy. The morphology of PLLA was investigated by scanning electron microscopy (SEM). The effects of the CO2-philic/lipophilic segment lengths of the stabilizers on the RODP were explored. The effects of the stabilizer concentration on the polymerization yield, molecular weight, and morphology of PLLA were investigated. [ABSTRACT FROM AUTHOR]

Curcumin is a natural phenolic pigment extracted from turmeric and has a good pharmacological activity in anti-inflammatory, antioxidant, hypolipidemic, and antitumor. It has been frequently used in drug-loaded microspheres recently. However, the reports on its solubility in supercritical fluids have not been seen yet. In the present study, solubility of curcumin in the supercritical carbon dioxide (ScCO2) was determined using the dynamic equilibrium method. The experimental measurements were performed at temperatures of 35, 45, and 55 °C and pressure range from 8 to 20 MPa. The measured data showed that the solubilities of curcumin were between 1.82 x 10-8 and 1.97 x 10-6 (mole fractin) for the corresponding temperatures and pressures. The effects of temperature, pressure, and with and without ethanol cosolvent on the solubility were investigated. The measured solubilities were calculated and correlated by semi-empirical formulas Chrastil and Mendez-Santiago and Teja models. The results showed that the experimental values of solubility were in good agreement with the theoretical ones, and the average absolute relative deviations (AARD) were 5.88% and 11.68% without cosolvent, and the AARD of the latter was 15.50% with the ethanol cosolvent. [ABSTRACT FROM AUTHOR]