The Interactions and Release Kinetics of Sodium Hyaluronate Implemented in Nonionic and Anionic Polymeric Hydrogels, Studied by Immunoenzymatic ELISA Test

Hyaluronan is a natural polymer that was introduced to wound therapy. Formulations based on synthetic polymers such as methylcellulose (MC) and polyacrylic acid (PA) containing hyaluronan (HA) were proposed for the development of prospective wound-healing preparations. The formulations of different carrier concentrations containing a fixed amount of HA were prepared, and their viscosity was measured. The HA release was evaluated by employing the apparatus paddle over a disc. The hydrogels were introduced to the donor chamber, and HA was released to the pH = 7.4 buffer. The amount of HA released was obtained using the ELISA test. The release was analyzed on the basis of different kinetic models: zero-, first-, and second-order kinetics, as well as Higuchi and Korsmeyer–Peppas equations. The release rate constants and the half release time were calculated from these equations. According to the value of the coefficient of the determination, the best model describing the observed process was selected. The comparison between the dissolution profiles was carried out by calculating the difference factor f1 and the similarity factor f2. The interaction between the hydrogel components was investigated by Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) measurements. The study revealed that the zero-order equation best described the release of HA from the formulations studied. The FTIR research and the DSC study showed the intermolecular interaction between HA chains in MC-based compositions, as well as between HA and the synthetic polymer in the PA-based formulations. The study revealed that the formulation with a higher concentration of synthetic polymer may prolong the release of HA. The obtained results indicated that the proposed hydrogels have potential for wound healing and may accelerate skin regeneration.

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.

First Use of Novel High Temperature Water-Based Reservoir Drilling Fluid to Access Depleted Deepwater Reserves

A combination of divalent base brine and high wellbore temperature presents significant challenges for high density aqueous reservoir drilling fluids. Such systems traditionally use biopolymers as viscosifiers; however, they are subject to degradation at elevated temperatures. Non-aqueous drilling fluids are thermally stable but complete removal of the filtercake is challenging and this can lead to formation damage. This paper describes the qualification and first deepwater drilling application of a unique aqueous reservoir drilling fluid at temperatures above 320°F. A high-temperature divalent brine-based reservoir drilling fluid (HT-RDF) and a solids-free screen running fluid (SF-SRF) were designed, both utilizing the same novel synthetic polymer technology. Calcium bromide brine was selected for use to minimize the total amount of acid-soluble solids in the drilling fluid. A comprehensive qualification was undertaken examining parameters such as rheology performance across a range of temperatures, long-term stability, fluid loss under expected and stress conditions (16 hours at 356°F), production screen test (PST), and various fluid-fluid compatibility tests. Return permeability tests were conducted on the final formulations to validate their suitability for use. The synthetic polymer technology provided excellent rheology, suspension, and fluid loss control in the fluid systems designed in the laboratory. To prepare for field execution multiple yard mixes were performed to verify the laboratory results on a larger scale. Additionally, a flow loop system was utilized to evaluate fluid performance under simulated downhole temperature and pressure conditions before field deployment. The final high temperature drilling fluid as designed provided rheological properties that met the necessary equivalent circulating density (ECD) requirements while drilling the reservoir. The fluid loss remained extremely stable and there were no downhole losses despite the depleted nature of the wellbore. Production screens were run straight to total depth (TD) with no wellbore stability issues after a three-day logging campaign. High temperature aqueous reservoir drilling fluids have historically been limited by the lack of suitable viscosifiers and fluid loss control additives. This paper outlines the design, mixing and logistical considerations and field execution of a novel polymer-based reservoir drilling fluid.

Occurrence of microdebris in commercial cephalopod

Modern Fish Market of Muara Baru is one of the largest fish markets in Jakarta, which sells various seafood, including fish, shellfish, crustaceans, and others. Previous studies have revealed microdebris contamination of mollusks, particularly in filter-feeders. However, it has not been widely studied at the predator level in cephalopods. We aim to investigate contamination of microdebris in two commercial species of cephalopod, i.e. Loliolus sumatrensis and Sepia recurvirostra, from the market. The digestive tract of the cephalopod was taken and dissolved by adding H2O2 50% then filtered under a vacuum system. The particles of microdebris were observed with a stereo microscope then several particles were analyzed using an FTIR microscope. The abundance of microdebris in L. sumatrensis was higher (3.8 particles/individual) than the abundance that of microdebris in S. recurvirostra (2.8 particles/individual). The size of microdebris was dominated by three of five size classes such as 0.1 − 0.5 mm, 0.5 − 1 mm, and 1 − 5 mm. Microdebris in L. sumatrensis was confirmed as polypropylene (PP), a synthetic polymer (microplastic), while in S. recurvirostra was confirmed as rayon (semi-synthetic). This research shows that microdebris contamination has reached the level of a predator in Mollusca.

New Hydrogel Network Based on Alginate and a Spiroacetal Copolymer

This study reports a strategy for developing a biohybrid complex based on a natural/synthetic polymer conjugate as a gel-type structure. Coupling synthetic polymers with natural compounds represents an important approach to generating gels with superior properties and with potential for biomedical applications. The study presents the preparation of hybrid gels with tunable characteristics by using a spiroacetal polymer and alginate as co-partners in different ratios. The new network formation was tested, and the structure was confirmed by FTIR and SEM techniques. The physical properties of the new gels, namely their thermal stability and swelling behavior, were investigated. The study showed that the increase in alginate content caused a smooth increase in thermal stability due to the additional crosslinking bridges that appeared. Moreover, increasing the content of the synthetic polymer in the structure of the gel network ensures a slower release of carvacrol, the encapsulated bioactive compound.