Preparation of mcl-polyhydroxyalkanoate nanoparticles stabilized by the Tween 80 nonionic surfactant

Nanoparticles based on biodegradable polymers find numerous applications in medicine as substances for intracellular drug delivery. Biosynthetically produced poly-3-hydroxyalkanoates (P3HAs) are among the most promising polymers of a lipid nature. In particular, polyhydroxybutyrate and polyhydroxyvalerate (scl-poly-3-hydroxyalkanoates) are widely used compounds, which are soluble only in organochlorine solvents. The use of organochlorine solvents faces several obstacles, since such chemicals may exhibit carcinogenic effects on the human body. However, the P3Has compounds consisting of hydroxybutyric acid residues with 6–14 carbon atoms in the main chain (mcl-poly-3-hydroxyalkanoates) are soluble not only in CHCl₃ or CH₂Cl₂ but also in paraffins. These hydrocarbons, such as n-hexane, can be easily separated from aqueous solutions and are not known to exhibit high cytotoxicity. Consequently, the application of mcl-poly-3-hydroxyalkanoates can prevent the contamination of prepared dosage forms with organochlorine compounds. To this end, a methodology for the synthesis of mcl-P3HA nanoparticles stabilized with the Tween 80 nonionic surfactant was proposed. The ratio between the concentration of P3HA and the detergent was optimized. The present study revealed that the obtained particles have an average size of 200±90 nm and a zeta potential of -17±5 mV. Upon investigating the stability of the particle solution at 4 °C, it was found that the nanoparticles did not alter their size and zeta potential for 90 days. The fluorescence microscopy method showed that they could be delivered into BHK-21 cells within 2 h. In addition, the nanoparticles synthesized had no toxic effect on BHK-21 cells at a concentration of up to 200 μg/mL.