Preliminary Studies on Solid Lipid Microparticles of Loratadine for the Treatment of Allergic Reactions via the Nasal Route

Purpose: To formulate solid lipid microparticles (SLM) of loratadine (LRT) for the treatment of allergic reactions via the nasal route.
Methods: Microparticles were prepared by emulsion congealing technique. The drug content of microparticles was analysed. Drug/excipient compatibility and crystallinity characteristics of microparticles were investigated by Fourier Transform Infrared Spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Particle size distribution was determined by laser diffraction (LD). Drug release from microparticles was compared to that from conventional vehicles (O/W emulsion, gel and oleageneous cream) using Franz-type diffusion cells.
Results: Drug content of microparticles was > 87.96 %. FT-IR and DSC analysis indicated that the drug and excipients were compatible for at least 6 months at room temperature after production. Microparticle size was between 86 ± 5.63 µm and 184 ± 13.21 µm while mean droplet size of O/W emulsion was 76 ± 3.45 µm. Release profiles of LRT from microparticles were significantly different from those of O/W emulsion, gel and oleageneous cream (p < 0.05). In the case of conventional vehicles, increase in the hydrophilicity of the vehicles led to increase in drug release rate. Drug release fitted generally to zero order kinetics as well as Korsmeyer-Peppas model for one of the SLM formulations, indicating non-Fickian drug release (super case II transport).
Conclusion: SLM provided LRT release for a longer period than the conventional vehicles. However, in vivo studies are required to ascertain the effectiveness of the formulations.

Keywords
Loratadine; Solid lipid microparticles; Allergy; Controlled drug delivery; Transnasal delivery