Development of Dipeptide N-acetyl-L-cysteine Loaded Nanostructured Carriers Based on Inorganic Layered Hydroxides.

N-acetyl-L-cysteine (NAC), a derivative of the L-cysteine amino acid, presents antioxidant and mucolytic properties of pharmaceutical interest. This work reports the preparation of organic-inorganic nanophases aiming for the development of drug delivery systems based on NAC intercalation into layered double hydroxides (LDH) of zinc-aluminum (Zn2Al-NAC) and magnesium-aluminum (Mg2Al-NAC) compositions. A detailed characterization of the synthesized hybrid materials was performed, including X-ray diffraction (XRD) and pair distribution function (PDF) analysis, infrared and Raman spectroscopies, solid-state 13carbon and 27aluminum nuclear magnetic resonance (NMR), simultaneous thermogravimetric and differential scanning calorimetry coupled to mass spectrometry (TG/DSC-MS), scanning electron microscopy (SEM), and elemental chemical analysis to assess both chemical composition and structure of the samples. The experimental conditions allowed to isolate Zn2Al-NAC nanomaterial with good crystallinity and a loading capacity of 27.3 (m/m)%. On the other hand, NAC intercalation was not successful into Mg2Al-LDH, being oxidized instead. In vitro drug delivery kinetic studies were performed using cylindrical tablets of Zn2Al-NAC in a simulated physiological solution (extracellular matrix) to investigate the release profile. After 96 h, the tablet was analyzed by micro-Raman spectroscopy. NAC was replaced by anions such as hydrogen phosphate by a slow diffusion-controlled ion exchange process. Zn2Al-NAC fulfil basic requirements to be employed as a drug delivery system with a defined microscopic structure, appreciable loading capacity, and allowing a controlled release of NAC.

Nanoemulsion containing caffeine for cellulite treatment: characterization and in vitro evaluation

The Ginoide Hydrolipodystrophy (GHLD), commonly known as cellulite, occurs in 80-90% of the female population after the puberty period and comes from a metabolic modification in the cutaneous adipose tissue. Caffeine has been used in topical formulations due to its lipolytic action. We studied a nanoemulsion (F3) containing caffeine with two surfactants (oleth-3 and oleth-20) by emulsification method by phase inversion temperature inversion (PIT). The polydispersion indices (PDI) showed the reduced deviation of 0.1. The mean droplet size was ~ 40 nm. The evaluated constant of Ostwald, in the refrigerator condition was the most favorable during the stability test. In the In Raman spectroscopy assay, the caffeine bands found in F3 were compatible with those found in the caffeine solution (1337, 652.5 and 558.2 cm-1). There was no interaction of caffeine anhydrous with other ingredients in nanoemulsion. In the in vitro safety assay the result of 1.4 ranked the F3 as slightly irritating. In the natural membrane, cutaneous permeation test (human skin) permeate concentrations did not exceed the saturation concentration of the PBS buffer (48.96 µg/3 mL). The caffeine solution and F3 permeated statistically equal, but the nanoemulsion visually and sensorially improved the caffeine precipitation.