Development of 3D-Printed, Liquisolid and Directly Compressed Glimepiride Tablets, Loaded with Black Seed Oil Self-Nanoemulsifying Drug Delivery System: In Vitro and In Vivo Characterization

Glimepiride is characterized by an inconsistent dissolution and absorption profile due to its limited aqueous solubility. The aim of this study was to develop glimepiride tablets using three different manufacturing techniques, as well as to study their quality attributes and pharmacokinetics behavior. Black seed oil based self-nanoemulsifying drug delivery system (SNEDDS) formulation was developed and characterized. Glimepiride liquisolid and directly compressed tablets were prepared and their pre-compression and post-compression characteristics were evaluated. Semi-solid pastes loaded with SNEDDS were prepared and used to develop three-dimensional printing tablets utilizing the extrusion technique. In vivo comparative pharmacokinetics study was conducted on Male Wistar rats using a single dose one-period parallel design. The developed SNEDDS formulation showed a particle size of 45.607 ± 4.404 nm, and a glimepiride solubility of 25.002 ± 0.273 mg/mL. All the studied tablet formulations showed acceptable pre-compression and post-compression characteristics and a difference in their in vitro drug release behavior. The surface of the liquisolid and directly compressed tablets was smooth and non-porous, while the three-dimensional printing tablets showed a few porous surfaces. The inner structure of the liquisolid tablets showed some cracks and voids between the incorporated tablet ingredients while that of the three-dimensional printing tablets displayed some tortuosity and a gel porous-like structure. Most of the computed pharmacokinetic parameters improved with the liquisolid and three-dimensional printed tablets. The relative bioavailabilities of the three-dimensional printed and liquisolid tablets compared to commercial product were 121.68% and 113.86%, respectively. Therefore, the liquisolid and three-dimensional printed tablets are promising techniques for modifying glimepiride release and improving in vivo performance but more clinical investigations are required.

Geotechnical and Environmental Assessment of Blast Furnace Slag for Engineering Applications

The increasing demand for building materials in the road industry creates interest for a new source of high-quality aggregates. In order to conserve natural resources, more attention is focused on anthropogenic soils and industrial solid wastes. For the successful application of these types of soil, a series of geotechnical and environmental tests have to be conducted. A potential hazard in the reuse of wastes from thermal degradation in the construction industry, particularly in reinforced concrete (RC) construction, is the migration of heavy metals into the groundwater environment. In this article, a geotechnical assessment of blast furnace slag (BFS) properties is presented. We conducted a series of CBR, and oedometric tests to evaluate the feasibility of BFS application in earth construction. The oedometric test results show acceptable compression characteristics which are in the range of natural aggregates. The CBR shows that this material may be used as a pavement subbase. We also noticed the preconsolidation pressure phenomenon in both Proctor and vibro-compacted soil during the oedometric test. The compression index and recompression index value show that the compression characteristics are close to those of dense sand. Based on the results described in the article, blast furnace slag is a candidate for technological application and can become one of the elements of sustainable development by contributing to a reduction in the negative environmental impact of production and use of building materials.

Design and Evaluation of Losartan Potassium Effervescent Floating Matrix Tablets: In Vivo X-ray Imaging and Pharmacokinetic Studies in Albino Rabbits

Losartan potassium (LP) is an angiotensin receptor blocker used to treat hypertension. At higher pH, it shows poor aqueous solubility, which leads to poor bioavailability and lowers its therapeutic effectiveness. The main aim of this research was to develop a direct compressed effervescent floating matrix tablet (EFMT) of LP using hydroxyl propyl methylcellulose 90SH 15,000 (HPMC-90SH 15,000), karaya gum (KG), and an effervescent agent, such as sodium bicarbonate (SB). Therefore, an EFMT has been developed to prolong the stomach residence time (GRT) of a drug to several hours and improve its bioavailability in the stomach region. The blended powder was evaluated for pre-compression characteristics, followed by post-compression characteristics, in vitro floating, water uptake studies, and in vitro studies. The optimized formulation of EFMT was investigated for in vivo buoyancy by X-ray imaging and pharmacokinetic studies in Albino rabbits. The results revealed that the parameters of pre- and post-compression were within the USP limits. All tablets showed good floating capabilities (short floating lag time <1 min and floated for >24 h), good swelling characteristics, and controlled release for over 24 h. The Fourier-transform infrared (FTIR) and differential scanning calorimetry (DSC) spectra showed drug–polymer compatibility. The optimized formulation F3 (HPMC-90SH 15,000-KG) exhibited non-Fickian diffusion and showed 100% drug release at the end of 24 h. In addition, with the optimized formulation F3, we observed that the EFMT floated continuously in the rabbit’s stomach area; thus, the GRT could be extended to more than 12 h. The pharmacokinetic profiling in Albino rabbits revealed that the relative bioavailability of the optimized LP-EFMT was enhanced compared to an oral solution of LP. We conclude that this a potential method for improving the oral bioavailability of LP to treat hypertension effectively.

Experimental Investigation of the Static and Dynamic Compression Characteristics of Limestone Based on Its Initial Damage

In the current work a new equation for initial damage assessment of limestone based on plane strain theory is proposed. Detailed investigations of the static and dynamic characteristics of limestone with different initial damage degree, using longitudinal wave speed, and static-dynamic compression tests are performed. This study investigated the static and dynamic characteristics of limestone with different initial damage degree, using longitudinal wave speed, and static-dynamic compression tests. Experimental results show that the degree of initial damage decreases with increasing longitudinal wave speed, which reaches the minimum when the longitudinal wave speed is approximately 6000 m/s, and the smaller the longitudinal wave velocity, the greater the degree of initial damage. The static and dynamic compressive strengths of limestone increase with the longitudinal wave velocity and strain rate, but the elastic modulus and Poisson’s ratio do not change significantly. Finally, based on the experimental results, the definitions of damage threshold value and strain softening are proposed, which further verify the influence of strain rate and initial damage on rock compression characteristics. The present study sheds light on the importance of initial damage for the mechanical state of rock in underground engineering.

A comparative analysis of the compression characteristics of a thermoplastic polyurethane 3D printed in four infill patterns for comfort applications

Purpose Most support surfaces in comfort applications and sporting equipment are made from pressure-relieving foam such as viscoelastic polyurethane. However, for some users, foam is not the best material as it acts as a thermal insulator and it may not offer adequate postural support. The additive manufacturing of such surfaces and equipment may alleviate these issues, but material and design investigation is needed to optimize the printing parameters for use in pressure relief applications. This study aims to assess the ability of an additive manufactured flexible polymer to perform similarly to a viscoelastic foam for use in comfort applications. Design/methodology/approach Three-dimensional (3D) printed samples of thermoplastic polyurethane (TPU) are tested in uniaxial compression with four different infill patterns and varying infill percentage. The behaviours of the samples are compared to a viscoelastic polyurethane foam used in various comfort applications. Findings Results indicate that TPU experiences an increase in strength with an increasing infill percentage. Findings from the study suggest that infill pattern impacts the compressive response of 3D printed material, with two-dimensional patterns inducing an elasto-plastic buckling of the cell walls in TPU depending on infill percentage. Such buckling may not be a beneficial property for comfort applications. Based on the results, the authors suggest printing from TPU with a low-density 3D infill, such as 5% gyroid. Originality/value Several common infill patterns are characterised in compression in this work, suggesting the importance of infill choices when 3D printing end-use products and design for manufacturing.