Preparation of Poly(3-hydroxybutyrate) Micro- and Nanoparticles as Hydrophobic Drugs Carrier Using Self-emulsifying Nanoemulsion Method

Aims: To correlate the different sizes and morphologies of polymeric particles prepared through the oil-in-water micro- and nanoemulsions.

Study Design: Poly(3-hydroxybutyrate) (PHB) micro- and nanoparticles were prepared using oil-in-water micro- and nanoemulsions based on the sodium dodecyl sulfate (SD) micellar system.

Place and Duration of Study: Chemistry Institute of São Carlos at University of São Paulo, São Carlos, São Paulo, Brazil, between September 2012 and June of 2014.

Methodology: The microemulsion domains of the sodium dodecyl sulfate (SD) micellar system were obtained by the pseudo-ternary phase diagram. The self-emulsifying nanoemulsions were formed by low-energy method by addition of NaCl to SD micellar system. Poly(3-hydroxybutyrate) particles were prepared using the in micro- and nanoemulsion domains determined. The encapsulation of Ibuprofen (IBU) was performed only via nanoemulsion method. The average size and size distribution of both the micellar systems and the polymeric particles were determined by dynamic light scattering (DLS, Zetasizer Nano-ZS, Malvern). The samples also were analyzed using the by Fourier transformed infrared spectroscopy (FTIR Prestige-21), PerkinElmer's LAMBDA 35 UV/Vis Spectrophotometer (Perkin Elmer) and by scanning electron microscopy (Zeiss LEO 440).

Results: Polymeric particles with different sizes and morphologies were prepared through the oil-in-water micro- and nanoemulsions. However, DLS measurements indicated that the precipitation of PHB did not occur inside micelles, but by an interfacial precipitation process. Despite, varying the oil content in microemulsion system, polymeric microparticles were obtained, while nanoparticles with size distribution around with 250-710 nm were prepared in nanoemulsion domain. The nanoemulsion method was used for encapsulating ibuprofen. Results indicated a non-Fickian release profile with biphasic pattern, with release around with 91.4% at 48 h.

Conclusion: The nanoemulsion method presented more suitable than microemulsion for preparing polymeric nanoparticles, as well to encapsulate lipophilic drugs, demonstrating versatility for future applications in biomedical area as versatile carrier.