Lyotropic liquid crystal mesophases as transdermal delivery systems for lipophilic drugs: A comparative study.

The present work aimed to evaluate different Liquid Crystal Mesophases (LCM) as transdermal drug delivery systems (TDDS) for nifedipine (NFD), a lipophilic drug model. The formulations composed of water, Citrus sinensis essential oil (CSEO), PPG-5-CETETH-20, and Olive oil ester PEG-7 were obtained and characterized by polarized light microscopy (PLM), rheology, small-angle x-ray scattering (SAXS), Fourier transform infrared coupled with an attenuated total reflection accessory (FTIR-ATR) and in vitro assays: bioadhesion, drug release, skin permeation, and retention tests. As a result, changes in component proportions led to several transparent viscous systems with an anisotropic profile. PLM and SAXS proved the presence of lamellar (S1), hexagonal (S3), and lamellar + hexagonal (S2) LCM, and rheology showed a high viscoelasticity profile. LCMs were able to adhere to the skin, and S2 achieved higher adhesion strength. NFD (5 mg/mL) has not modified the organization of LCMs. Results also showed that S3 promoted higher permeation and retention and higher disorganization of stratum corneum lipids, which is the main permeation-enhancing mechanism. Thus, the formulations obtained can carry and improve drug delivery through the skin and are promising TDDS for lipophilic drug administration, such as NFD.

Chitosan-functionalized nanostructured lipid carriers containing chloroaluminum phthalocyanine for photodynamic therapy of skin cancer.

The objective of this study was to obtain optimized nanostructured lipid carriers (NLC) functionalized with chitosan containing chloroaluminum phthalocyanine (ClAlPc) as a photosensitizer. Initially, the optimization of the preparation method of the NLC was performed, where the influence of different surfactants such as PVA and Tween 80, as well as different solid lipids such as stearic acid and Glycerol Monostearate (GM) was evaluated. The formulation containing GM and PVA (NLC10) was considered promising. Following, by the adsorption method (NLC10q), the formulation was functionalized with chitosan and characterized. NLC10 and NLC10q presented sizes of 131.5 and 231.5 nm, and ZP of -24.30 and + 19.96 mV, respectively. The encapsulation efficiency of NLC10q was 96 %, higher than NLC10 (79 %). The formulations were able to promote significant cutaneous retention of ClAlPc, after 2 h and 4 h of the study, and showed to be non-toxic to fibroblasts (biocompatible). PDT in BF16-F10 melanoma resulted in reduced cell viability to 70 % and 50 % for NLC10 and NLCq, respectively. In view of the results obtained, NLC showed to be promising in the treatment of skin cancer through PDT. NLC10q showed higher encapsulation efficiency and stability than NLC10, but, contrary to what was expected, it presented lower photodynamic efficiency.