Thermosensitive liposomes containing cisplatin functionalized by hyaluronic acid: preparation and physicochemical characterization

This study aimed to develop a thermosensitive liposomal formulation (TSL) functionalized with hyaluronic acid (HA), to encapsulate a hydrophilic drug, the cisplatin (CDDP). The physicochemical and thermal characteristics of this new formulation were studied by dynamic light scattering (DLS), microcalorimetry, and small-angle X-ray scattering (SAXS) techniques. Our results showed mean diameter and PDI data characteristics of homogeneous formulations, indicating the absence of aggregation of vesicles after functionalization with HA. The efficiency of coating in the liposome surface was attributed to zeta potential values close to neutrality. DLS data showed a significant reduction in the average diameter and Kcps of the formulations evaluated at 40 °C. It was also observed that the HA-coating did not alter the Tm of the formulations. The SAXS profile of all formulations was characteristic of a lamellar organization regardless of temperature evaluated and showed dilation of the bilayer, caused by local misorientation in the structure of the lipids, confirming the conformational alteration due to warming. Therefore, the in vitro release profile showed that possible drug adsorption in the phospholipid bilayer may be generating the diffusion rate of CDDP before reaching Tm (42 °C), for TSL-CDDP and TSL-CDDP-SA-HA. For TSL-CDDP-HA, the presence of the polymer may be modulating this diffusion, generating a more controlled and slow release profile.