Factorial design approach to fabricate and optimize floating tablets based on combination of natural polymer and rice bran wax

Background The aim of the present research work was to fabricate a novel gastroretentive drug delivery system in the form of tablets using a combination of natural polymer and rice bran wax with an intention to control drug delivery and to enhance the gastric residence time of the model drug Famotidine in the gastrointestinal tract. Results The results of the preliminary trial batches prepared by using the hot melt granulation technique resulting in six different formulations showed good physicochemical characteristics and tablets conformed to the Pharmacopoeial specifications. Gastroretentive tablets containing natural polymer showed prolonged drug release comparable to Methocel. The optimized formulation (C3) using 32 factorial design showed FLT 27 ± 2.47 s, SI 92.68 ± 1.36% and % CDR 98.89 ± 0.39% at 12 h. The stability studies indicated the stability of the formulation during storage. Conclusions It was concluded that the release profile fitted best to zero-order equation with non-Fickian diffusion mechanism of drug release which demonstrates swelling-controlled drug release mechanism. Thus, the formulated tablets have the potential for improved release and gastroretentive properties. Graphical Abstract

Development of Silk Fibroin Scaffolds by Using Indirect 3D-Bioprinting Technology

Due to the excellent biocompatibility of natural polymers, a variety of natural polymers have been widely used as biomaterials for manufacturing tissue engineered scaffolds. Despite the excellent biological activity of natural polymers, there have been obstacles in using them on their own to prepare 3D scaffolds with sufficient mechanical strength. Although multiple 3D-bioprinting technologies have recently emerged as effective manufacturing tools for scaffold preparation, scaffold preparation using only natural polymers with tunable mechanical properties is still difficult. Herein, we introduce novel scaffold fabrication methods using the natural polymer silk fibroin via indirect 3D-bioprinting technology. The developed silk fibroin scaffolds showed biocompatibility and tunable mechanical strength by changing the concentration of the silk fibroin. Furthermore, controlling the flexibility of the silk fibroin scaffolds was made possible by changing the solvent for the silk fibroin solution used to fabricate the scaffold. Consequently, silk fibroin scaffolds fabricated via our method can be considered for various applications in the bioengineering of either soft or musculoskeletal tissues.

An experimental investigation of viscosity of a newly developed natural polymer-based media for abrasive flow machining (AFM) of 3D printed ABS parts

Abrasive Flow Machining (AFM) is the method of finishing complex surfaces and internal channels with the help of extrusion pressure and abrasive-laden viscoelastic polymer media. This paper is based on developing a new AFM media using a natural waste polymer as a base material. In the article, a natural polymer media viz. rice husk ash-based media has been developed, and subsequently, rheological analysis has been done, and experimentation has been performed on Anton-paar® rheometer to optimize the viscosity of these newly developed AFM media. In this research study, the hollow elliptical shape of ABS (acrylonitrile-butadiene-styrene) material was manufactured using the FDM technique and then finished with a one-way AFM machine. This paper examined the parametric dependencies of AFM process parameters on finishing FDM printed hollow elliptical parts. The improved surface roughness of the FDM printed hollow elliptical parts has been investigated relating to the AFM process parameters. The maximum surface roughness has been achieved by 95.98%.

Biodegradable Hydrogel Scaffolds Based on 2-Hydroxyethyl Methacrylate, Gelatin, Poly(β-Amino esters), and Hydroxyapatite

New composite 3D scaffolds were developed as a combination of synthetic polymer, poly(2-hydroxyethyl methacrylate) (PHEMA), and a natural polymer, gelatin, with a ceramic component, nanohydroxyapatite (ID nHAp) dopped with metal ions. The combination of a synthetic polymer, to be able to tune the structure and the physicochemical and mechanical properties, and a natural polymer, to ensure the specific biological functions of the scaffold, with inorganic filler was applied. The goal was to make a new material with superior properties for applications in the biomedical field which mimics as closely as possible the native bone extracellular matrix (ECM). Biodegradable PHEMA hydrogel was obtained by crosslinking HEMA by poly(β-amino esters) (PBAE). The scaffold’s physicochemical and mechanical properties, in vitro degradation, and biological activity were assessed so to study the effects of the incorporation of nHAp in the (PHEMA/PBAE/gelatin) hydrogel, as well as the effect of the different pore-forming methods. Cryogels had higher elasticity, swelling, porosity, and percent of mass loss during degradation than the samples obtained by porogenation. The composite scaffolds had a higher mechanical strength, 10.14 MPa for the porogenated samples and 5.87 MPa for the cryogels, but a slightly lower degree of swelling, percent of mass loss, and porosity than the hybrid ones. All the scaffolds were nontoxic and had a high cell adhesion rate, which was 15–20% higher in the composite samples. Cell metabolic activity after 2 and 7 days of culture was higher in the composites, although not statistically different. After 28 days, cell metabolic activity was similar in all scaffolds and the TCP control. No effect of integrating nHAp into the scaffolds on osteogenic cell differentiation could be observed. Synergetic effects occurred which influenced the mechanical behavior, structure, physicochemical properties, and interactions with biological species.

Effective Management of Rare Lymphangioleiomyomatosis Using Sirolimus: Tablet Matrix with Hibiscus rosa sinensis Leave Mucilage

The authors aimed to extend the discharge of Sirolimus from the tablets with a blend of herbal and synthetic polymers. In this study, Sirolimus was taken as a model drug, Hydroxy Propyl Methyl Cellulose as a synthetic polymer and mucilage from Hibiscus rosa sinensis leaves as a natural polymer. Sirolimus is an orphan drug used to treat Lymphangioleiomyomatosis damage and to suppress body refuse towards the transplanted organs. Sirolimus matrix tablets made with the blend of Hibiscus rosa sinensis leaves mucilage and Hydroxy Propyl Methyl Cellulose. The blend was assessed for flow possessions and the designed tablets were categorized for official and non-official tests including Sirolimus discharge. The Sirolimus matrix tablets possess good Sirolimus content with passible pre and post-formulation parameters. The study concludes that there were no chemical interactions between Sirolimus with polymers used. The study also revealed that Hibiscus rosa sinensis leaves mucilage can be a good polymer in grouping with other polymers for prolonged drug discharge.

Formulation Development and Evaluation of Doxofylline Sustained-Release Tablets by Using Chitosan and Guar Gum

The sustained-release dosage form is a well-characterized and reproducible dosage form that is designed to control drug release profile at a certain rate to reach desired drug concentration in blood plasma or at the target site. There is immense demand in the market for new sustained-release formulations used for new drug molecules which release the drug at a sustained rate. Doxofylline is one of the widely useful drugs in the market and needs to be given in a single dose for a long duration of time. For the same, we have prepared a sustained released Doxofylline tablet. Aim: This research was done to design, formulate and evaluate Doxofylline sustained-release tablets by using different concentrations of Chitosan and Guar Gum. Methods: The factorial design was used to prepare Doxofylline sustained-release tablet. Doxofylline sustained-release tablets were prepared to employ different concentrations of Chitosan, Guar Gum, Lactose, and Magnesium Stearate in different combinations by wet granulation technique. Total 9 formulations were designed, formulated, and evaluated for the hardness, thickness, friability, % drug content, and in-vitro drug release. Results: A study of the release of drug by in-vitro found that F8 is to be the best efficient formulation which consists of both Chitosan and Guar Gum helped in delayed the release of drug up to 24 hours and performs excellent release of drug in starting hours of drug release in the body. The drug released from the F8 formulation indicates the kinetic model of First Order, by anomalous diffusion. The formulation F8 shows optimum thickness, hardness and at 40ºC±2 99.35% drug release after 24 hours shows optimum formulation. Conclusion: This study concludes that better drug release was observed by using natural polymers. Doxofylline with natural polymer shows good release and better dissolution rate as compared with a single synthetic polymer. Synthetic drug with natural polymer shows more future scope and this work will help the researcher in the future.

Utilization of Cellulose to Its Full Potential: A Review on Cellulose Dissolution, Regeneration, and Applications

As the most abundant natural polymer, cellulose is a prime candidate for the preparation of both sustainable and economically viable polymeric products hitherto predominantly produced from oil-based synthetic polymers. However, the utilization of cellulose to its full potential is constrained by its recalcitrance to chemical processing. Both fundamental and applied aspects of cellulose dissolution remain active areas of research and include mechanistic studies on solvent–cellulose interactions, the development of novel solvents and/or solvent systems, the optimization of dissolution conditions, and the preparation of various cellulose-based materials. In this review, we build on existing knowledge on cellulose dissolution, including the structural characteristics of the polymer that are important for dissolution (molecular weight, crystallinity, and effect of hydrophobic interactions), and evaluate widely used non-derivatizing solvents (sodium hydroxide (NaOH)-based systems, N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl), N-methylmorpholine-N-oxide (NMMO), and ionic liquids). We also cover the subsequent regeneration of cellulose solutions from these solvents into various architectures (fibers, films, membranes, beads, aerogels, and hydrogels) and review uses of these materials in specific applications, such as biomedical, sorption, and energy uses.