Modulation of Epidermal Growth Factor Release by Biopolymer-Coated Liposomes.

This work describes the development of polysaccharide-coated liposomes to modulate the delivery of epidermal growth factor (EGF), with the aim to produce different EGF release profiles depending on the milieu of infected wounds. For this purpose, cationic liposomes were coated with one layer of sodium alginate (ALG) followed by one layer of chitosan (CHI) using the layer-by-layer (LbL) technique. The coated liposomes exhibited apparent hydrodynamic diameters of 278 ± 36 and 216 ± 96 nm for Lip-ALG and Lip-ALG-CHI, respectively. Thus, it appears that adding the CHI layer compacted the Lip-ALG one. The incorporation efficiency of EGF was a maximum of 55% for liposomes with a polymeric coating. In vitro release experiments showed that Lip-ALG-CHI exhibits a higher release rate constant under acidic pH conditions, resembling those of infected tissue. Using an ex vivo model of EGF release in porcine ear skin, these liposomes were found to accumulate in the epidermis. Thus, coated liposomes could represent a local EGF delivery mechanism to promote healing.

Influence of the extraction time on macromolecular parameters of galactomannans.

This study evaluated the aqueous extraction of galactomannans from the seeds of Mimosa scabrella (GM), Stryphnodendron adstringens (GS) and Schizolobium parahybae (GG) for 1, 2, 3, 4, 6, 24 and 48 h. The efficiency of extraction processes was assessed in terms of yield, carbohydrate and protein content. The extraction process, as well as the source of the galactomananns generated molecules with differences in molar mass, viscosity and rigidity analyzed by HPSEC-MALLS/RI/VIS. The extraction time results for each species, based on minimum extraction time and HPSEC-MALLS/RI/VIS results, were 4 h (GM4h), 6 h (GS6h) and 2 h (GG2h) for GM, GS and GG, respectively. In most cases, the apparent persistence length, as determined by viscometry, indicated that aggregates remained in galactomannans after centrifugation and filtration. Results suggest an effective extraction time for each plant source of galactomannan based on its performance and its macromolecular behavior in solution.

Topical curcumin-loaded hydrogels obtained using galactomannan from Schizolobium parahybae and xanthan.

The curcumin (CUR)-loaded binary hydrogel was formulated using xanthan and galactomannan from Schizolobium parahybae (guapuruvu). The binary hydrogels presented gel characteristics, stable pH values and mechanical stress resistance even after 45 days of heat exposure (45 °C). The CUR-loaded hydrogel content was 98.6% for XGMC (xanthan and galactomannan with CUR-microemulsion) after the stability test. The in vitro cytotoxicity analysis suggested non-cutaneous membrane irritation, and the in vitro skin permeation analysis indicated 2.15 to 2.50 µg mL(-1) CUR at the stratum corneum, epidermal and dermal levels. The XGEC (xanthan and galactomannan with CUR solubilized in ethanol) and XGMC hydrogels presented 76.8 and 63.2% inhibition of topical inflammation, respectively. Chemical stability and non-cytotoxicity analysis confirm the safety of prolonged exposure of the skin during the topical treatment, offering long-lasting XGEC and XGMC action.