Printability assessment of psyllium husk (isabgol)/gelatin blends using rheological and mechanical properties.

The primary goal of this study is to highlight the rheological and mechanical properties of a new blend composed of naturally-derived hydrogel materials- psyllium husk (PH) and gelatin (G) for its potential use in three-dimensional (3D) printing technology. The mixtures were prepared at various weight ratios of 100PH, 75PH + 25G and 50PH + 50G. A suitable selection of the printable ink was made based on the preliminary screening steps of manual filament drop test and layer stacking by 3D printing. Printing of the common features such as hexagon and square grids helped evaluating shape fidelity of the chosen ink. Although 50PH + 50G blend was found meeting most of the criteria for an ideal 3D printable ink, rheological and mechanical characterizations have been performed for all the ratios of polymeric blends. This study documents the correlation between various factors of rheology that should be taken into account while categorizing any biomaterial as a printable ink. Yield stress was measured as 18.59 ± 4.21 Pa, 268.74 ± 13.56 Pa and 109.16 ± 9.85 Pa for 50PH + 50G, 75PH + 25G and 100PH, respectively. Similarly, consistency index (K) and flow index (n) were calculated using the power law equation and found as 49.303 ± 4.17, 530.59 ± 10.92, 291.82 ± 10.53 and 0.275 ± 0.04, 0.05 ± 0.005, 0.284 ± 0.04 for 50PH + 50G, 75PH + 25G and 100PH, respectively. The loss modulus (G″) was observed dominating over storage modulus (G') for 50PH + 50G, that depicts its liquid-like property; whereas storage modulus (G') was found dominating in case of 75PH + 25G and 100PH, indicating their solid-like characteristics. In addition, the loss tangent value (tan δ) of 50PH + 50G was observed exceeding unity (1.05), supporting its plastic behavior, unlike 75PH + 25G (0.5) and 100PH (0.33) whose loss tangent values were estimated less than unity revealing their elastic behavior. Also, 50PH + 50G was found to have the highest mechanical strength amongst the three blends with a Young's modulus of 9.170 ± 0.0881 kPa.

Ex-vivoand in-vitro assessment of mucoadhesive patches containing the gel-forming polysaccharide psyllium for buccal delivery of chlorhexidine base.

The aim of the present study was to evaluate the gel-forming polysaccharide psyllium in the preparation of mucoadhesive patches for the controlled release of chlorhexidine (CHX) to treat pathologies in the oral cavity, using the casting-solvent evaporation technique. A number of different film-forming semi-synthetic polymers, such as sodium carboxymethyl cellulose (SCMC) and hydroxypropylmethyl cellulose (HPMC) were evaluated for comparison. The patch formulations were characterized in terms of drug content, morphology surface, swelling and mucoadhesive properties, microbiology inhibition assay and in vitro release tests. Three ex-vivo testswere carried out using porcine mucosa: an alternative dissolution test using artificial saliva that allows contemporary measurement of dissolution and mucoadhesion, a permeation test through the mucosa and the measurement of mucoadhesion using a Nouy tensile tester, as the maximum force required for the separation of the patch from the mucosa surface. The patches were also examined for determination of the minimum inhibitory concentration in cultures of Escherichia coli and Staphylococcus aureus. All the patches incorporating psyllium were found suitable in terms of external morphology, mucoadhesion and controlled release of the drug: in the presence of psyllium the drug displays prolonged zero-order release related to slower swelling rate of the system.

Formulation and optimization of alkaline extracted ispaghula husk microparticles of isoniazid - in vitro and in vivo assessment.

Microparticles containing isoniazid were prepared by the emulsification internal ionic gelation method using a novel, alkaline extracted ispaghula husk as a wall forming material. A four-factor three-level Box-Behnken design was employed to study the effect of independent variables on dependent variables. Sodium alginate concentration (X(1)), alkaline extraction of ispaghula husk (AEISP) concentration (X(2)), concentration of cross-linking agents (X(3)) and stirring speed (X(4)) were four independent variables considered in the preparation of microparticles, while the particle size (Y(1)) and entrapment efficiency (Y(2)) were dependent variables. Optimized microparticles exhibited 83.43% drug entrapment and 51.53 µm particle size with 97.80% and 96.37% validity, respectively, at the following conditions - sodium alginate (3.55% w/v), alkaline extracted ispaghula husk (3.60% w/v), cross-linker concentration (7.82% w/v) and stirring speed (1200 rpm). The optimized formulation showed controlled drug release for more than 12 h by following Higuchi kinetics via non-Fickian diffusion. The gamma scintigraphy of the optimized formulation in Wistar rats showed that microparticles could be observed in the intestinal lumen after 1 h and were detectable in the intestine up to 12 h, with decreased percentage of radioactivity (t(1/2) of (99m)Tc 4-5 h).

A low-cost ultrasound phantom of the lumbosacral spine.

BACKGROUND AND OBJECTIVES: This report describes the production of a low-cost ultrasound phantom of the lumbosacral spine. The phantom should be a very useful tool to teach the basic skills for ultrasound-guided procedures of the lumbosacral spine. METHODS: A lumbosacral spine model is secured to the bottom of a microwave-safe container and is immersed in a concentrated gelatin solution. After the gelatin hardens, the model can be used for scanning practice as well as needle placement. The phantom can be recovered after use by melting the gelatin in a microwave to "erase" any needle track marks. RESULTS: A transparent and durable gelatin block is produced. This allows trainees to have direct visual access to the lumbosacral spine model to correlate with the ultrasound images as well as to confirm proper needle placement. Disadvantages of the model include lack of simulated soft tissue structures and an absence of simulated haptic feedback during needle placement. Metamucil can be added to the gelatin to simulate the appearance of soft tissue, although this increases the opacity and thus decreases the visual access of the gelatin. CONCLUSIONS: This teaching tool can provide trainees with an opportunity to familiarize themselves with sonoanatomy of the lumbosacral spine in addition to practicing probe handling techniques and needle placement.