Phase equilibria and mechanical properties of gel-like water-gelatin-locust bean gum systems

Semisolid Extrusion 3D Printing of Propranolol Hydrochloride Gummy Chewable Tablets: an Innovative Approach to Prepare Personalized Medicine for Pediatrics

The demand for personalized medicine has received extensive attention, especially in pediatric preparations. An emerging technology, extrusion-based 3D printing, is highly attractive in the field of personalized medicine. In this study, we prepared propranolol hydrochloride (PR) gummy chewable tablets tailored for children by semisolid extrusion (SSE) 3D printing technology to meet personalized medicine needs in pediatrics. In this study, the effects of critical formulation variables on the rheological properties and printability of gum materials were investigated by constructing a full-factorial design. In addition, the masticatory properties, thermal stability, and disintegration time of the preparations were evaluated. Bitterness inhibitors were used to mask the bitterness of the preparations. The results of the full-factorial design showed that the amount of gelatin and carrageenan were the key factors in the formulation. Gelatin can improve printability and masticatory properties, carrageenan can improve thermal stability, and accelerate the disintegration of preparations; therefore, a reasonable combination of both could satisfactorily meet the demand for high-quality 3D printing. γ-Aminobutyric acid can reduce the bitterness of gummy chewable tablets to improve medication compliance and the determined formulation (F7) met the quality requirements. In conclusion, the gum material has excellent potential as an extrusion material for 3D printing. The dosage can be adjusted flexibly by the model shape and size. 3D printing has broad prospects in pediatric preparations.

Preparation and Performance of Thickened Liquids for Patients with Konjac Glucomannan-Mediated Dysphagia

The present study sought to characterize the rheological and thickening properties of Konjac glucomannan (KGM) and prepare thickening components for special medical purposes using KGM and maltodextrin as the primary raw materials and guar gum (GG), xanthan gum (XG), locust bean gum (LBG), and carrageenan (KC) as the supplemented materials. The formulation and preparation processes were optimized through single factor experiments taking sensory evaluation as an indicator. The results confirm that KGM had excellent thickening performance, reaching about 90 times its own mass. The optimal formulation process of the thickening components based on KGM was as follows: the mass concentration of the compound thickener (KGM/GG/XG/LBG/KC = 13:2:2:2:1) was 5.0–7.0 mg/mL; the maltodextrin concentration was 10.0 mg/mL; the brewing temperature of the thickening component was 60 °C with no restriction on consumption time. The rheology test results revealed that the thickening components had shear thinning characteristics, which could provide three different thickening effects of nectar-thick level (350 mPa·s), honey-thick level (1250 mPa·s), and pudding-thick level (1810 mPa·s) suitable for people with different degrees of chewing disorders. Overall, this study provides a theoretical basis and technical reference for KGM as a dietary nutrition support for patients with dysphagia.

Embedded 3D Printing of Novel Bespoke Soft Dosage Form Concept for Pediatrics

Embedded three-dimensional printing (e-3DP) is an emerging method for additive manufacturing where semi-solid materials are extruded within a solidifying liquid matrix. Here, we present the first example of employing e-3DP in the pharmaceutical field and demonstrate the fabrication of bespoke chewable dosage forms with dual drug loading for potential use in pediatrics. Lego^TM-like chewable bricks made of edible soft material (gelatin-based matrix) were produced by directly extruding novel printing patterns of model drug ink (embedded phase) into a liquid gelatin-based matrix (embedding phase) at an elevated temperature (70 °C) to then solidify at room temperature. Dose titration of the two model drugs (paracetamol and ibuprofen) was possible by using specially designed printing patterns of the embedded phase to produce varying doses. A linearity [R² = 0.9804 (paracetamol) and 0.9976 (ibuprofen)] was achieved between percentage of completion of printing patterns and achieved doses using a multi-step method. The impact of embedded phase rheological behavior, the printing speed and the needle size of the embedded phase were examined. Owning to their appearance, modular nature, ease of personalizing dose and geometry, and tailoring and potential inclusion of various materials, this new dosage form concept holds a substantial promise for novel dosage forms in pediatrics.

Gel-embedded niosomes: preparation, characterization and release studies of a new system for topical drug delivery

In the present paper physical gels, prepared with two polysaccharides, Xanthan and Locust Bean Gum, and loaded with non-ionic surfactant vesicles, are described. The vesicles, composed by Tween20 and cholesterol or by Tween85 and Span20, were loaded with Monoammonium glycyrrhizinate for release experiments. Size and zeta (ζ)-potential of the vesicles were evaluated and the new systems were characterized by rheological and dynamo-mechanical measurements. For an appropriate comparison, a Carbopol gel and a commercial gel for topical applications were also tested. The new formulations showed mechanical properties comparable with those of the commercial product indicating their suitability for topical applications. In vitro release experiments showed that the polysaccharide network protects the integrity of the vesicles and leads to their slow release without disruption of the aggregated structures. Furthermore, being the vesicles composed of molecules possessing enhancing properties, the permeation of the loaded drugs topically delivered can be improved. Thus, the new systems combine the advantages of matrices for a modified release (polymeric component) and those of an easier permeability across the skin (vesicle components). Finally, shelf live experiments indicated that the tested gel/vesicle formulations were stable over 1 year with no need of preservatives.

Cleaning of paper artworks: development of an efficient gel-based material able to remove starch paste

The removal of old glue from paper artworks is of paramount importance for the preservation of its integrity during the restoration process. Wet cleaning is one of the traditional methods, although it may cause damages on artworks. In this work, an advantageous alternative method, based on the use of a rigid hydrogel, for a simple and localized removal of starch paste from paper supports is presented. The use of an appropriate hydrogel allows to overcome many of the problems faced by restorers minimizing damages, through a controlled release of water to the artwork, and a simple and not invasive application and removal. At the same time, the specific and targeted enzyme activity leads to a significant reduction in the application time of the cleaning procedure. In this context, experiments were carried out applying Gellan hydrogel carrying α-amylase enzyme on several paper samples soiled with starch paste. To assess the cleaning efficacy of the proposed hydrogel, we have used a multidisciplinary approach, by means of spectroscopic techniques, scanning electron microscopy, chromatographic analysis, and pH investigations.

Characterization of polysaccharide hydrogels for modified drug delivery

Hydrogels are hydrophilic macromolecular networks that are capable of retaining a large amount of water. A precise description of these systems is actually quite complex and the practical use of hydrogels for drug delivery and biomedical applications is often not supported by a well-defined knowledge of the overall structure of the polymeric network. In this paper, we report the characterization of two different systems: a chemical network based on Guar Gum (GG) and a physical gel prepared with Xanthan (Xanth) and Locust Bean Gum (LBG). The dynamo-mechanical properties of the gels were analysed: the cohesiveness and the adhesion of the networks were strongly dependent on time, temperature, and composition. The kinetics of the chemical crosslinking was followed by means of rheological measurements, i.e. recording the mechanical spectra of the gelling system, and the power law exponent at the gel point was evaluated. Furthermore, the networks, loaded with model drugs with different steric hindrance, were used as matrices for tablets and the rate of release of such model drugs was studied. The diffusion of the guest molecules was deeply dependent on their dimensions; in the case of Xanth-LBG tablets the release profiles were almost independent from the different cohesion properties of the starting hydrogel composition.

A new polysaccharidic gel matrix for drug delivery: preparation and mechanical properties

A new type of hydrogel was prepared, under controlled conditions, by diffusion of Ca(II) ions into a solution of the carboxylated derivative of Scleroglucan (Sclerox). The obtained hydrogel was loaded with Theophylline (TPH) and Myoglobin (MGB), two model drugs of remarkably different steric hindrance, and also used, after freeze drying, for the preparation of tablets. Release studies were carried out on both the freshly prepared gel and on the tablets. As far as the gel systems experiments are concerned, the delivery profiles resulted to be deeply dependent on the molecular dimensions of the loaded molecules; TPH was easily released while the larger tested molecule (MGB) remained partially entrapped within the three-dimensional network. Furthermore, in the case of MGB, the release was dependent also on polymer concentration (c(p)): at the highest investigated c(p) value a corresponding lowest delivery of the guest molecule was observed. This effect of polymer concentration on the rate of delivery was studied applying three different mathematical approaches: the one that better fitted the experimental release profile allowed to support the explanation of the mechanism involved in the observed two-step delivery that has been related to the drug trapping inside the clusters of the gel network. The delivery profiles from the tablets showed how the release, in this case, could be related, essentially, to the molecular dimensions of the guest molecules, independently on the c(p) used to prepare the starting hydrogel. TPH was completely delivered in a few hours while the MGB was almost unable to diffuse out of the matrix and more than 80% resulted entrapped in the network for at least 24 h. The novel hydrogel, at different c(p), was also characterized by means of a texture analyzer to inspect its mechanical properties. According to the compression data, the hardness, the work of cohesion and the work of adhesion of the networks were estimated. Furthermore, by means of relaxation experiments, analysed applying the generalized Maxwell model, the gels can be classified as solid viscoelastic materials and the mechanical spectra indicated a predominance of the viscous behaviour, while the Young modulus, E0, as expected, was found to increase with polymer concentration.

Structural and rheological characterization of Scleroglucan/borax hydrogel for drug delivery

The polysaccharide Scleroglucan, one of the most rigid polymers found in nature, can form a chemical/physical gel, in the presence of borax. The obtained hydrogel was loaded with three different model molecules (Theophylline, Vitamin B12 and Myoglobin) and then, after freeze-drying, was used as a matrix for tablets. The release profiles of the substances from the dosage forms were evaluated; the matrix appeared capable to modulate the diffusion of the chosen molecules, and different diffusion rates were observed, according to the different radii of the tested molecules. Interestingly, in the dissolution medium the matrix undergoes an anisotropic swelling taking place only in the axial direction, while a negligible radial variation occurs. The water uptake of the matrix occurs according to a Fickian process. Samples at two different polymer concentrations (0.7 and 2.3%, w/v) were characterized in terms of rheological and mechanical parameters and the properties were interpreted in terms of the molecular structure obtained by conformational analysis. The flow curves acquired in the viscoelasticity interval, show the effect of the borate ion in improving the resistance of the gel in comparison to the polymer alone. The evaluation of the moduli indicates that the system is viscoelastic, with an appreciable liquid component that increases as the polymer concentration decreases. Also the cohesion of the gel is higher in comparison to the Scleroglucan and is strongly dependent on temperature. The combination of experimental and theoretical conformational analysis approaches, allowed us to propose a model for the structure of the macromolecular network and to give an explanation to the anomalous swelling that was observed. It came out that the polymer can built up a channel structure, mediated via borax ion interaction, that can accommodate guest molecules of different size.

Phase-separation-induced fractionation in molar mass in aqueous mixtures of gelatin and dextran

An overview of the effects of phase separation of aqueous mixtures of gelatin and dextran on the fractionation in molar mass of these two components is given. Molar mass distributions in coexisting phases were investigated using size exclusion chromatography with multiangle laser light scattering. The initial molar mass of the native material, concentration, and temperature were varied. The results show a strong fractionation in molar mass for both components. The molar mass of the native material and concentration appeared to be the only factors that affected the final molar mass distributions, temperature having no effect. The results show that in the molar mass range where fractionation is the strongest, i.e., roughly below the maximum in the distribution, fractionation is governed by a Boltzmann factor e(-deltaG/kT), where deltaG denotes the free energy involved in transferring a polymer with a certain length from the enriched to the depleted phase, and in this case turns out to be proportional to the molar mass. Comparison of the results of phase separation with results on dialysis shows that water affinity is not the driving force for the phase separation of gelatin and dextran in aqueous solution. The gelation properties of gelatin in both phases were also determined. The gelation properties of gelatin in the coexisting phases differ from those of native gelatin. In particular, the gelatin in the gelatin-poor phase shows strong differences compared to the native material.