Preliminary Evaluation of 3D Printed Chitosan/Pectin Constructs for Biomedical Applications.

In the present study, chitosan (CS) and pectin (PEC) were utilized for the preparation of 3D printable inks through pneumatic extrusion for biomedical applications. CS is a polysaccharide with beneficial properties; however, its printing behavior is not satisfying, rendering the addition of a thickening agent necessary, i.e., PEC. The influence of PEC in the prepared inks was assessed through rheological measurements, altering the viscosity of the inks to be suitable for 3D printing. 3D printing conditions were optimized and the effect of different drying procedures, along with the presence or absence of a gelating agent on the CS-PEC printed scaffolds were assessed. The mean pore size along with the average filament diameter were measured through SEM micrographs. Interactions among the characteristic groups of the two polymers were evident through FTIR spectra. Swelling and hydrolysis measurements confirmed the influence of gelation and drying procedure on the subsequent behavior of the scaffolds. Ascribed to the beneficial pore size and swelling behavior, fibroblasts were able to survive upon exposure to the ungelated scaffolds.

Preparation and Evaluation of Collagen-Based Patches as Curcumin Carriers.

Patients with psoriasis are dissatisfied with the standard pharmacological treatments, whether systemic or topical, with many of them showing interest in complementary and alternative medicine. Curcumin (Cur), a natural polyphenol derived from turmeric, has recently gained attention for skin-related diseases because of its proven anti-inflammatory action. However, topical treatment with Cur would be inadequate because of its hydrophobicity, instability, and low bioavailability. In addition, hyperkeratosis and lack of moisture in psoriatic skin result in low penetration that would prevent actives from permeating the stratum corneum. In this work, a polymer-based formulation of Cur for the topical treatment of psoriasis is reported. To improve the physicochemical stability of Cur, it was first encapsulated in chitosan nanoparticles. The Cur-loaded nanoparticles were incorporated in a hydrophilic, biocompatible collagen-based patch. The nanoparticle-containing porous collagen patches were then chemically cross-linked. Morphology, chemical interactions, swelling ratio, enzymatic hydrolysis, and Cur release from the patches were evaluated. All patches showed excellent swelling ratio, up to ~1500%, and after cross-linking, the pore size decreased, and their hydrolysis rates decelerated. The in vitro release of Cur was sustained with an initial burst release, reaching 55% after 24 h. Cur within the scaffolds imparted a proliferation inhibitory effect on psoriatic human keratinocytes in vitro.

Chitosan Nanoparticles with Encapsulated Natural and UF-Purified Annatto and Saffron for the Preparation of UV Protective Cosmetic Emulsions.

The aim of the present work is to evaluate the preparation of sunscreen emulsions based on chitosan (CS) nanoparticles with annatto, ultrafiltrated (UF) annatto, saffron, and ultrafiltrated saffron. Ionic gelation was used for the preparation of chitosan nanoparticles, while their morphological characteristics and physicochemical properties were evaluated via Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and dynamic light scattering (DLS). Results showed that the prepared nanoparticles ranged from ~150 to ~500 nm and had a spherical or irregular shape. In the case of annatto and UF annatto, due to the formation of H-bonds, the sunscreen agents were amorphously dispersed within CS nanoparticles, while in the case of saffron and UF saffron, crystalline dispersion was observed. All encapsulated materials had good thermal stability as well as color stability. In a further step, sunscreen emulsions were prepared based on the formed CS-sunscreen nanoparticles and evaluated for their stability in terms of pH and viscosity, along with their ultraviolet (UV) radiation protection ability in terms of sun protection factor (SPF). All prepared emulsions showed low cytotoxicity and good storage stability for up to 90 days, while minimum sunscreen protection was observed with SPF values varying from 2.15 to 4.85.

Felodipine nanodispersions as active core for predictable pulsatile chronotherapeutics using PVP/HPMC blends as coating layer.

In the present study predictable pulsatile chronotherapeutics of felodipine (FELO), which is a poorly-water soluble drug, were prepared in the form of two layered tablets. As active core PVP/FELO nanodispersion was used while as effective coating layer different PVP/HPMC blends were added. From dissolution studies of FELO nanodispersions it was revealed that PVP/FELO 90/10 w/w dispersion is an ideal system for pulsatile formulations since the whole amount of FELO is released within the first 30 min. This dissolution enhancement and fast release was attributed to FELO amorphisation, as was found from XRD and DMTA techniques and the effective particle size reduction. Transmission electron microscopy (TEM) studies revealed that FELO creates amorphous nanodispersions into the PVP matrix while particle sizes are directly dependable upon FELO concentration. Drug particles with sizes lower than 150 nm may be the optimal level for a substantial enhancement of FELO dissolution rate. The time of FELO release initiated by the two-layered tablets was adequately adjusted by using different PVP/HPMC blends as coating layer, which is a swellable and erodible barrier. The delaying time of FELO release is directly depended by HPMC concentration and this correlation was mathematically expressed. The significance of these blends is that they are completely miscible over the entire compositional range, thus forming a new matrix with different physicochemical properties, contrary to the initial polymers.