Hydroxypropyl Methylcellulose Solution Research Articles

Mass Spectrometry Imaging and Histology for the Analysis of Budding Intestinal Organoids.

Three-dimensional (3D) organoids have been at the forefront of regenerative medicine and cancer biology fields for the past decade. However, the fragile nature of organoids makes their spatial analysis challenging due to their budding structures and composition of single layer of cells. The standard sample preparation approaches can collapse the organoid morphology. Therefore, in this study, we evaluated several approaches to optimize a method compatible with both mass spectrometry imaging (MSI) and immunohistological techniques. Murine intestinal organoids were used to evaluate embedding in gelatin, carboxymethylcellulose (CMC)-gelatin-CMC-sucrose, or hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) solutions. Organoids were assessed with and without aldehyde fixation and analyzed for lipid distributions by MSI coupled with hematoxylin and eosin (H&E) staining and immunofluorescence (IF) in consecutive sections from the same sample. While chemical fixation preserves morphology for better histological outcomes, it can lead to suppression of the matrix-assisted laser desorption/ionization (MALDI) lipid signal. By contrast, leaving organoid samples unfixed enhanced MALDI lipid signal. The method that performed best for both MALDI and histological analysis was embedding unfixed samples in HPMC and PVP. This approach allowed assessment of cell proliferation by Ki67 while also identifying putative phosphatidylethanolamine (PE(18:0/18:1)), which was confirmed further by tandem MS approaches. Overall, these protocols will be amenable to multiplexing imaging mass spectrometry analysis with several histological assessments and help advance our understanding of the biological processes that take place in district subsets of cells in budding organoid structures.

Effects of Dipentaerythritol and Cellulose as Additives on the Morphology of Pentaerythritol Crystals

The crystal habit of pentaerythritol (PE) crystals is usually rod-shaped, which may lead to low bulk density and bad flowability compared with low aspect ratio crystals. In this study, dipentaerythritol (DPE), methylcellulose (MC), and hydroxypropyl methylcellulose (HPMC) were selected as additives to modify the morphology of PE crystals. In the presence of DPE, the bulk density of PE crystals was improved, and the aspect ratio was decreased. The modified attachment energy (AE) model was conducted to analyze changes in PE crystal habits in the presence of DPE, which characterizes the intensity of the interaction between DPE molecules and PE crystal faces. Spherical pentaerythritol crystals can be successfully prepared by adding MC and HPMC solution, and the formation mechanism can be divided into five steps.

Экспериментальное обоснование использования 1% раствора гидроксипропилметилцеллюлозы для защиты эндотелия заднего послойного трансплантата роговицы при его выкраивании низкоэнергетическим фемтосекундным лазером по инвертированной методике

Purpose. To evaluate experimentally endothelial cell loss of animal's cornea during inverted posterior lamellar corneal graft preparation technique by low-energy femtosecond laser with and without ophthalmic viscosurgical device (OVD) – 1% hydroxypropyl methylcellulose (HPMC) solution application. Material and methods. Posterior lamellar corneal grafts were created using a femtosecond laser (FSL). In the control group (n=16), a few drops of corneal storage solution were applied to the endothelium just before applanation, in the experimental group (n=16) – 1% HPMС. The quality of the applanation were monitored using an integrated in laser OCT system. The endothelial viability was determined using live/dead cells assay and the grafts were examined on a confocal laser scanning microscope. The obtained images were analyzed to count live and dead endothelial cells (EC). To assess the state of collagen fibers of the stromal side of the graft, samples from the control and experimental groups were examined using a scanning electron microscope (SEM). Results. According to the OCT, in all samples of both groups, a flat profile of the contact zone between the laser head and the endothelial monolayer was observed during applanation. The difference between the number of live and dead ECs was statistically significant between both groups. There were 2854 [2819; 2879] live cells/mm² in the control group, and 3477 [3426; 3719] live cells/mm² in the experimental group (p<0.001). Thus, the number of dead ECs in the control group was 710 [649; 728] cells/mm² . The number of dead ECs in the experimental group was 402 [366; 427] cells/mm² (p<0.001). When analyzing the images obtained on a SEM, the preservation of the architectonics of the graft collagen fibers with their single defibrations in both groups was observed. Conclusion. Application of 1% HPMC provides protection for endothelial cells from damage during posterior laser dissection using an FSL. In the study group, the number of endothelial cells was 9.92% higher than in the control group. The presence of the OVD layer in the interface between the head of the FSL and the EC did not affect the formation of an effective laser cut and did not reduce the quality of the stromal surface of the graft. The inverted technique FSL cut using a 1% solution of HPMC on the surface of the endothelium may be recommended for use in clinical practice. Key words: endothelium, keratocytes, corneal transplantation, keratoplasty, posterior lamellar keratoplasty, femtosecond laser, ophthalmic viscosurgical device, hydroxypropyl methylcellulose, confocal microscopy, scanning electron microscopy

Study on development and tissue permeation of different formulations of Fasudil.

The study is intended to formulate Fasudil loaded vesicular system for application in the management of angina. Fasudil was made into a complex with phospholipid, and other different formulations were made, including Fasudil solution, liposomal form, and Fasudil loaded into the gel. A drug characterization study was conducted and noted. Drug release was quantified and analyzed and, finally, inoculated in Sprague-Dawley rats. These rats underwent anginal induction, and each formulation's effect on angina was evaluated. Drug solution (F-Phos) and F-Phos-Lipo (liposomal dispersion form of the drug) have shown that more than half percent of them have been released within 1.5 hours, and the rapid release occurred from liposomal dispersion in the first hour. The study determined the viscosity of the different formulations, which was significantly (p<0.05) higher than the theoretical sum of the viscosity of each formulation. The study found that the F-Phos-Lipo+P-407HMS formulation is the most effective as its application has the minimum infarct area percentage compared to the other formulations and can also reduce creatine kinase levels significantly as compared to the different formulations (p<0.05). The study concluded that the typical gel formulation (liposomal Fasudil dispersed in hydroxypropyl methylcellulose solution, which is added to blank poloxamer 407) had been shown to have significantly anti-anginal properties, including easy administration, its application on the infarct area percentage and subsequently its pharmacological effect on the cardiac tissue.

Bioactive Materials Based on Hydroxypropyl Methylcellulose and Silver Nanoparticles: Structural-Morphological Characterization and Antimicrobial Testing

The progress achieved in recent years in the biomedical field justifies the objective evaluation of new techniques and materials obtained by using silver in different forms as metallic silver, silver salts, and nanoparticles. Thus, the antibacterial, antiviral, antifungal, antioxidant, and anti-inflammatory activity of silver nanoparticles (AgNPs) confers to newly obtained materials characteristics that make them ideal candidates in a wide spectrum of applications. In the present study, the use of hydroxypropyl methyl cellulose (HPMC) in the new formulation, by embedding AgNPs with antibacterial activity, using poly(N-vinylpyrrolidone) (PVP) as a stabilizing agent was investigated. AgNPs were incorporated in HPMC solutions, by thermal reduction of silver ions to silver nanoparticles, using PVP as a stabilizer; a technique that ensures the efficiency and selectivity of the obtained materials. The rheological properties, morphology, in vitro antimicrobial activity, and stability/catching of Ag nanoparticles in resulting HPMC/PVP-AgNPs materials were evaluated. The obtained rheological parameters highlight the multifunctional roles of PVP, focusing on the stabilizing effect of new formulations but also the optimization of some properties of the studied materials. The silver amount was quantified using the spectroscopy techniques (energy-dispersive X-ray fluorescence (XRF), energy-dispersive X-ray spectroscopy (EDX)), while formation of the AgNPs was confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS). Also, the morphological examination (Atomic Force Microscopy (AFM) and Scanning electron microscopy (SEM)) by means of the texture roughness parameters has evidenced favorable characteristics for targeted applications. Antibacterial activity was tested against Escherichia coli and Staphylococcus aureus and was found to be substantially improved was silver was added in the studied systems.

High viscosity hydroxypropyl methyl cellulose to improve inkjet printing for cotton/polyamide fabrics

When dyes were used for inkjet printing on multi-component fabrics, the complex acid-base conditions, high temperature and high humidity posed a challenge to the stability of water-soluble polymers covered the surface of the fabrics. In this study, hydroxypropyl methyl cellulose (HPMC) was used to construct a continuous film on the surface of cotton/polyamide interwoven fabric. The results show that the formation of ridges between fibers is closely related to the properties of HPMC. Fibers in the yarn were connected to each other by HPMC, which prevented inks from penetrating into the bottom of the yarns. Meanwhile, HPMC maintained high viscosity under acidic conditions, which provided conditions for reactive dyes to dye polyamide fibers under acidic conditions. Compare with sodium alginate, the color depth of cyan, magenta, yellow and black improved by 75.1 %, 101.8 %, 181.3 %, 207.5 % on cotton/polyamide fabrics using HPMC, separately. Hydroxypropyl methyl cellulose is effective to improve inkjet printing for cotton and polyamide fiber, which has the possibility of widespread application in natural fiber and synthetic fiber. • Hydroxypropyl methyl cellulose membrane is constructed to connect adjacent fibers. • The formation of ridge structure is due to the high viscosity of HPMC solution. • The ink penetration is constrained along the direction perpendicular to the fabric. • The inkjet printing effect of C/PA fabric is improved with the help of HPMC film.

Rheology of nano ZnO - Hydroxypropyl Methylcellulose (HPMC) based suspensions and structural properties of resulting films

Effect of polyethylene glycol (PEG) and ZnO nanoparticles concentration on rheological properties of the hydroxypropyl methylcellulose (HPMC) based film forming suspensions (FFS) and, on the structural properties of the resulting films were characterized. Rheological properties of FFS were not significantly affected by PEG concentration and ZnO NPs incorporation. Intrinsic viscosity [η] of aqueous HPMC solution obtained from extrapolation of Huggins and Kraemer plot was 0.115–0.118 (L/g). Coating thickness calculated as a function of coating solution viscosity, concentration and draining time for strawberry coating was 1.26–1.49 μm. Tensile strength (TS) of HPMC film decreased while water vapour permeability (WVP) increased with increasing PEG concentration. Elongation at break (%E) increased up to 25% PEG concentration and decreased afterward. Incorporation of ZnO NPs improved the tensile strength and barrier properties of HPMC film. Relaxation percentage and stress decay rate increased with increasing plasticizer concentration while decreased with incorporation of ZnO NPs. • Rheological behaviour of aqueous HPMC solution (4% w/v) was Newtonian. • Calculated Intrinsic viscosity [η] of aqueous HPMC solution was 0.115–0.118 (L/g). • Relaxation % and stress decay rate showed positive correlation with PEG concentration. • Added ZnO nanoparticles improves the HPMC film properties.

Synthesis of antibacterial hydroxypropyl methylcellulose and silver nanoparticle biocomposites via solution plasma using silver electrodes

The biocomposites of hydroxypropyl methylcellulose (HPMC)/silver nanoparticles (AgNPs) were synthesized using the solution plasma process (SPP). HPMC/AgNPs were synthesized in 1–5 % HPMC solutions using silver electrodes. UV–Vis spectroscopy showed a peak near 400 nm and the peak increased as the concentration of HPMC and discharge time increased. FTIR analysis indicated no change in the chemical structure of the HPMC based biocomposites. Spherical shaped AgNPs with size ranges about 2–18 nm and well dispersed in the porous HPMC matrices with fringed edges were observed by TEM and SEM/EDS analyses. The synthesized biocomposites were found to be thermo-stable by TGA analysis. The inhibition zones of bacterial growth formed by the HPMC/AgNPs biocomposites were in the range of 8–14.3 mm; minimal inhibition concentrations, in the range of 10–15 μg·mL−1 for Gram-negative bacteria; 25–30 μg·mL−1 for Gram-positive bacteria. The biocomposites were non-toxic to the HEK293 cells up to 125 μg·mL−1. The results indicated that the synthesis of antibacterial agents in the HPMC matrix using silver electrodes via SPP would be an efficient and safe way for the development of biopolymer based antimicrobials and wound healing biomaterials.

Development of Saturated Fat Replacers: Conventional and Nano-Emulsions Stabilised by Lecithin and Hydroxylpropyl Methylcellulose.

The combination of two emulsifiers, lecithin and hydroxypropyl methylcellulose (HPMC), into emulsions is an interesting strategy to design fat replacers in food matrices. The objective of this study was to investigate the effect of HPMC type and concentration on the formation, stability, and microstructure of conventional emulsions and nanoemulsions. Two different types of HPMC with low and high content of methyl and hydroxypropyl groups (HPMC-L and HPMC-H) were evaluated. The results showed that the molecular structure and concentration of HPMC play a major role in the viscoelastic behaviour, the gelation temperature, and the strength of gel formed. The firmness and work of shear of HPMC solutions increased significantly (p < 0.05) with increasing concentration. HPMC-L illustrated a more stable gel structure than the HPMC-H solution. Nanoemulsions showed lower moduli values, firmness, and work of shear than conventional emulsions due to the influence of high-pressure homogenization. A combination of lecithin and HPMC improved the physical and lipid oxidative stability of the emulsions, presenting a lower creaming index and thiobarbituric acid reactive substances (TBARS). In conclusion, HPMC-L at 2% w/w could be a suitable type and concentration combined with lecithin to formulate a saturated fat replacer that could mimic butter technological performance during food manufacturing operations.

STUDY OF BIODEGRADABLE FILMS BASED ON CELLULOSE ETHERS WITH BACTERICIDAL PROPERTIES

The article shows research on the development of the latest biodegradable films with bactericidal properties based on hydroxypropylmethylcellulose modified with brown coal humic acids. Hybrid biodegradable films with bactericidal properties were obtained by pouring solutions of hydroxypropylmethylcellulose with a concentration of 2 wt.%, to which different amounts of humic acid were added. When obtaining biodegradable films with bactericidal properties, hydroxypropylmethylcellulose of the Walocel™ brand manufactured by Dow Corning (USA) was used. As hybrid modifiers, humic acids were used, obtained by extraction of brown coal with an alkaline solution of sodium pyrophosphate, followed by extraction with a 1% sodium hydroxide solution and precipitation with mineral acid. Determination of water absorption of samples of biodegradable films in cold water was carried out according to ISO 62:2008, tensile strength properties of biodegradable films were determined according to ISO 527-2:2021, to measure the gas permeability of biodegradable films, the differential pressure method and a vacuum tester VAC-V1 were used. The effect of the hybrid modification of hydroxypropylmethylcellulose with lignite humic acids in terms of the studied performance characteristics increased in the direction of lignite humic acid types No. 3&gt; No. 2&gt; No. 1. It has been shown that hybrid modification by the mechanism of matrix synthesis of biodegradable films with bactericidal properties based on hydroxypropylmethylcellulose with brown coal humic acids makes it possible to reduce their water absorption, increase the basic strength characteristics and impart antibacterial properties to them, which is confirmed by the data on the time of mold appearance. Optimum in terms of strength and performance characteristics are biodegradable films with bactericidal properties at a content of 10% wt. humic acids No. 3. In general, it has been established that hybrid modification with humic acids according to the mechanism of matrix synthesis of biodegradable films based on hydroxypropylmethylcellulose makes it possible to obtain durable water-soluble films with antibacterial properties for use as packaging for dry food products (bread, cereals, nuts, etc.) with an extended shelf life. storage.

Development of xanthan gum/hydroxypropyl methyl cellulose composite films incorporating tea polyphenol and its application on fresh-cut green bell peppers preservation

The aim of this work was to develop an edible packaging material with good performance that can be used for fresh-cut vegetables preservation. The xanthan (XG)-hydroxypropyl methylcellulose (HPMC)-tea polyphenols (TP) composite film (XHT) was prepared by adding TP to the composite film-forming solution of XG and HPMC. At optimum TP dosage of 6% (XHT6), the tensile strength and elongation at break were at the maximum. The antioxidant activity and antibacterial properties were also enhanced, demonstrated good inhibitory ability to Staphylococcus aureus. After 8 days, the amount of Vitamin C that was retained by XHT6 was 127.81% and 7.83% higher than unpackaged and XHT0, respectively. Additionally, the MDA content in green peppers were 39.16% and 78.87% higher than that of unpackaged and XHT0, respectively. Practical applications of XHT films in preserving fresh-cut bell peppers had also shown positive results, making it possible as potential food packaging.

HPMC Hydrogel Formation Mechanisms Unveiled by the Evaluation of the Activation Energy.

Aqueous solutions of hydroxypropyl methylcellulose (HPMC) show inverse thermoreversible gelation, i.e., they respond to small temperature variations exhibiting sol–gel transition during heating, and reversibly gel–sol transition during cooling. According to the pertinent literature on HPMC aqueous systems, at room temperature, the loss modulus (G”) is higher than the storage modulus (G’). During the heating ramp, the viscoelastic response follows a peculiar path: initially, G” and G’ smoothly decrease, then drop to a minimum and finally increase. Eventually, G’ overcomes G”, indicating the gel formation. A recent explanation of this behaviour considers a two-step mechanism: first, phase separation occurs, then fibrils form from a polymer-rich phase and entangle, leading to a three-dimensional network. Based on this, our research focuses on the rheological analysis of the different steps of the sol–gel transition of an HPMC aqueous solution. We perform different viscoelastic tests: thermal ramps, time sweeps, and frequency sweeps at selected characteristic temperatures. We couple classical analysis of the SAOS experiments with an innovative approach based on the evaluation of the activation energy (Ea), made possible by the instrument intrinsic temperature oscillations around the target value. Results show that Ea can be a valid tool that contributes to further clarifying the peculiar microstructural evolution occurring in this kind of thermoreversible gel.

Effect of Hydroxypropyl methylcellulose from oil palm empty fruit bunch on oil uptake and physical properties of French fries

Oil palm empty fruit bunches (OPEFB) can be used as raw material for Hydroxypropyl Methylcellulose (HPMC). HPMC can be used as a French fries coating to reduce oil uptake. This research aims to study the utilization of HPMC OPEFB as a French fries coating. This research consists of two stages. The first stage is cellulose extraction and HPMC synthesis. HPMC synthesis through alkalization, methylation, propylation, and neutralization. The second stage is the use of HPMC as a French fries coating with different concentrations (0, 1, 2, and 3%). Potatoes that have been peeled and washed, cut lengthwise with a thickness of about 0.5 cm. Further dipped in HPMC solution with different concentrations for 10 seconds, then carried out a frying pan. The HPMC from OPEFB is characterized by methyl and hydroxypropyl groups found at a wavenumber of 2891.30 cm-1, a ring of pyranose at 995.79 cm-1 and hydroxyls (OH) groups at 3371.10 cm-1. The coating of French fries with 3% HPMC OPEFB can reduce oil absorption by 16.09%. The higher the concentration of HPMC, will reduce the fat content but increase the moisture and the texture of French fries become softer. The preferred type of coating was HPMC 1%.

Hydroxypropyl methylcellulose-based films embedded with garlic oil- loaded chitosan microparticles as a potential oral mucosal drug delivery system

In the present study, hydroxypropyl methylcellulose (HPMC)-based films embedded with garlic oil- loaded chitosan microparticles were characterized and evaluated for their suitability as a potential oral mucosal drug delivery system concerning bacterial infections. Chitosan was used to encapsulate garlic oil and form microparticles using different weight ratios by ionic gelation technique. The microparticles were then incorporated into HPMC solution and films were fabricated using the film casting technique. A blank film without microparticles was also prepared. The microparticles were examined for their particle size, uniformity, shape, zeta potential and antimicrobial activities. The results suggest that the microparticles exhibit a spherical shape, are electrically unstable and tend to agglomerate due to having low zeta potential (-7.06 to -1.24 mV). Nevertheless, they showed antimicrobial activities against both Escherichia coli and Staphylococcus aureus. Additionally, the films were characterized by weight, thickness, wettability and antimicrobial activities. All films produced were generally light (0.20 to 0.25 g), thin (0.02 to 0.12 mm) and had good wettability based on their low contact angles (below 90°). In comparison to the microparticles, the films exhibited antimicrobial activity against S. aureus whereas no zone of inhibition was observed when the films were tested against E. coli. HPMC-based films embedded with encapsulated garlic oil have the potential to act as a new drug treatment to treat oral mucosal bacterial infections. Additional studies should be performed to evaluate the effectiveness of this treatment, such as extensive physicochemical characterization, mucoadhesion studies and evaluation of drug release and drug permeation across the oral mucosa.

Feeding silkworms with HPMC dispersed MoO2 NPs: An efficient strategy to enhance the supercapacitance performance of carbonized silk

It was found in our previous study that feeding silkworms with MoO2 nanoparticles (NPs) as a food additive enabled the incorporation of MoO2 NPs into the as-spun silk, which, in turn, can be used to build electrodes for energy storage. However, aggregation of the MoO2 NPs was observed at high fractional feeding dosages. In order to disperse the MoO2 NPs in fibrous silk and enhance the specific capacitance of the carbonized silk more effectively, a 0.5% (w/v) hydroxypropyl methyl cellulose (HPMC) solution was utilized as the dispersant in this work. Transmission electron microscopy (TEM) results confirmed that HPMC increased the separation of MoO2 nanoparticles incorporated within the silk matrix. Furthermore, the electrochemical performance was characterized, revealing that the specific capacitance of carbonized silk from this HPMC-MoO2 NP feeding group reached 456 F/g, compared to the value of 245 F/g from the previous study, at a current density of 0.2 A/g, demonstrating a significant improvement. The feasibility of utilizing HPMC to maintain the segregated state of MoO2 NPs throughout all stages of silk encapsulation, with negligible impact of this feeding regimen on the growth of silkworms, is demonstrated in this work.

Biomechanical Response After Corneal Cross-linking With Riboflavin Dissolved in Dextran Solution Versus Hydroxypropyl Methylcellulose.

To evaluate corneal stiffening in porcine eyes induced by corneal cross-linking (CXL) using riboflavin dissolved in either aqueous dextran or hydroxypropyl methylcellulose (HPMC) solution. Fifty-one porcine corneas were divided into three groups of 17 each. After deepithelialization, the first (Dresden) group was treated for 30 minutes with 0.1% riboflavin (riboflavin-5-monophosphate in 0.9% NaCl) dissolved in hypertonic 20% dextran and the second (HPMC) group for 30 minutes with isotonic solution containing 0.1% riboflavin and 1.1% HPMC. Thereafter, corneas of both groups were irradiated using 5.4 J/cm2 (irradiance of 9 mW/cm2 for 10 minutes; 10*9). After CXL, all corneas were kept in an isotonic 16% dextran bath for 2 hours to obtain an equal hydration state. The third group served as the control group. Stress-strain measurements were performed on 5-mm-wide strips. Corneal thickness was monitored throughout the entire course of the experiments. The required stress for a 10% strain was increased by 83% in the Dresden group and 35% in the HPMC group compared to the control group. Resultant Young's modulus (at 10% strain) was 2.53 ± 0.73, 1.87 ± 0.50, and 1.47 ± 0.44 Pa for the Dresden, HPMC, and control groups, respectively. The differences between the Dresden and HPMC groups (P = .006), the Dresden and control groups (P < .001), and the HPMC and control groups (P = .014) were statistically significant. Pachymetry measurements showed a significantly increased corneal thickness after application of HPMC compared with the Dresden group (P = .002) and control group (P = .041). The biomechanical stiffening of the cornea by CXL can be achieved using dextran- and HPMC-based riboflavin solutions in porcine corneas with an application time of 30 minutes. Dextran-based riboflavin solutions seem to induce a slightly stronger biomechanical response in this setting. HPMC solutions induce less thinning than dextran solutions. [J Refract Surg. 2021;37(9):631-635.].

Structural, mechanical and thermal properties of gamma irradiated SF_HPMC blend films

Introduction: The properties of the silk fibroin can be improved by blending silk with some other biopolymers. The improvement in properties of the blend depends on the degree of compatibility or miscibility of the polymers at the molecular level (1). Depending upon the degree of molecular mixing, blends can be compatible, semi-compatible or incompatible. Gamma irradiation is one of the techniques used to promote the compatibility between the individual polymer molecules of the polymer blends. Here gamma irradiation is performed in order to investigate the effect of gamma radiation on the silk fibroin blends, which may be useful for development of silk fibroin blends for biomedical applications in the future. The goal of this study was to prepare and characterize SF_HPMC blend films, aiming at an insoluble film, with a more stable and crystalline structure. Later the blend film was exposed to gamma radiation of different doses. Methods: The Silk Fibroin solution was prepared from Bombyx mori CSR4 bivoltine cocoons. Prepared SF solution was added with Hydroxypropyl Methylcellulose solution of same weight percentage (5 wt%), with constant stirring at room temperature. The final solution mixture is tuned into free standing flexible film of SF_HPMC by solution casting method. Gamma irradiation of SF_HPMC blend films was done at CARRT centre, Mangalore university, using Cobalt-60 source, with a dose range of 0-250 kGy (50 kGy interval) at a dose rate of 7.065 kGy/h. The average energy of the gamma photons was 1.25 MeV. The irradiation was carried at normal temperature and pressure. Structural property of the samples was studied by using Rigaku Miniflex-II, X-ray Diffractometer. Mechanical studies of the sample were done by universal testing machine (Zwick Roell Z020, Germany) according to ASTM D882. Thermal properties of the samples were studied using TA instruments, SDT Q600 analyzer. Results & Discussions: The XRD results suggested that both α-helical (silk I) and β sheet (silk II) components were present in the SF_HPMC irradiated with the high doses of gamma radiation. It also seems that up to 100 kGy of gamma energy the composition of silk fibroin and its crystal conformation did not change significantly. The increase in doses of gamma radiation increases the crystallite sizes and decreases the lattice strain slightly. Mechanical strength analysis shows the breaking strength and elongation at break of SF_HPMC films showed almost a linear downward trend due to free radical formation, chain scissions, and disordering of silk fibroin chains due to the breakage of hydrogen bonds and peptide bonds in amorphous region, which results loss of the average molecular orientation in the polymer assembly. The thermal stability of SF_HPMC blend film decreases with gamma irradiation, which is due to the weakening of molecular interactions between SF and HPMC components and decrease in the percentage composition of silk II (β- sheet components). Conclusions: It was found from results that the increase in the energy of incident gamma radiation the thermal stability and mechanical strength of the SF_HPMC blend films decreased. Also, the structural and chemical properties of the blend films were slightly altered with increase in the dose of gamma radiation. The various characterization techniques used here to study the properties of the gamma radiated Silk fibroin-HPMC blend revealed that when silk fibroin materials were sterilized by gamma irradiation smaller radiation doses should be used, otherwise irreversible damages (breakdown of secondary bonds and covalent bonds) on the materials would be caused. Keywords: Silk fibroin, Gamma irradiation, structural properties, chemical, mechanical, thermal properties References Shetty GR, Rao BL, Asha S, Wang Y, Sangappa Y, Preparation and Characterization of Silk Fibroin/Hydroxypropyl Methyl Cellulose (HPMC) Blend Films. Fiber Polym, 2015;16(8):1734-1741.

Экспериментальное обоснование применения вископротекции эндотелия роговичного трансплантата для задней послойной кератопластики, сформированного при помощи фемтосекундного лазера

Purpose. To rationale experimentally the use of a viscoprotection of the corneal endothelium on the graft formed with a femtosecond laser for the descemet stripping endothelial keratoplasty. Material and methods. In our study, we used 12 pig's corneoscleral discs. The preservation time before the experiment averaged 12±4 hours. The corneas were divided into 2 groups. In the operating room, the graft was formed using an LDV Z8 femtosecond laser (Ziemer, Switzerland) from the endothelial side. Before applanation of the donor cornea and femtolaser head, a 1% solution of hydroxypropyl methylcellulose (HPMC) was applied to the endothelium - experimental group. The control group was appraised according to the standard technique, with the application of a few drops of a solution for storing the corneas. Then the applanation was monitored and evaluated by laser optical coherence tomography. Then the graft was separated from the bed and transferred to a conservation medium. Under laboratory conditions, to determine the viability of endothelial cells, the graft was stained with a «vital» dye with the commercial name Life and Dead (Abcam, UK) and placed in a confocal laser scanning microscope. Endothelial cells were counted using the ImageJ software. Results. In the experimental and control groups, the number of living endothelial cells (EC) was 91.06±1.49% and 83.86±2.14%, respectively (p&lt;0.001). The number of dead ECs in the control group was 7.2±0.65% more than in the experimental group and amounted to 16.14±2.14% and 8.94±1.49%, respectively (p&lt;0.001). Conclusion. The study demonstrated that the use of viscoprotection of the corneal graft endothelium for posterior lamellar keratoplasty is quite effective, and significantly reduces the loss of EC at the stage of cutting out the graft with a femtosecond laser. Key words: descemet stripping endothelial keratoplasty, femtosecond laser, vital dyes.

Production of oral films based on pre-gelatinized starch, CMC and HPMC for delivery of bioactive compounds extract from acerola industrial waste

The residue from the processing of acerola, due to the concentration of active compounds, and antioxidant potential has aroused interest in its application. In this context, this study aimed to produce and characterization oral films based on carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC) and pre-gelatinized starch with the incorporation of ethanolic extract of dehydrated acerola industrial waste (EEDAIW) using tape-casting technique. The rheological properties of filmogenic solutions of CMC, HPMC, and starch were assessed. Oral films were characterized in relation to color parameters, mechanical properties, surface pH, contact angle, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy, and stability in relation to total phenolic compounds. It was found that apparent viscosity decreased with the deformation rate and the expected behavior of pseudoplastic fluids, regardless of the polymer used. In general, the addition of EEDAIW in the films led to a reduction in the tensile strength of the films and an increase in the contact angle values; however, the surface pH of the films remained close to the oral pH (6.8). From the FTIR, it was found that even after the addition of EEDAIW, all films showed predominant absorption bands, characteristic of the polymer used. It was found that after 84 days, CMC-based films had a higher concentration of total phenolic compounds when compared to HPMC and starch oral films.

Impact of Mixing on Content Uniformity of Thin Polymer Films Containing Drug Micro-Doses.

The impact of mixer type and critical process parameters (CPPs) on critical quality attributes (CQAs), including the drug content uniformity (CU) of slurry-cast polymer films loaded with micro-sized poorly water-soluble drugs were investigated. Previously untested hypothesis was that the best mixer at suitable CPPs promotes uniform drug dispersion within film precursors leading to acceptable dried-film CU at low, ~0.6 wt% drug concentrations. Taguchi design was utilized to select the best of three mixers; low-shear impeller, high-shear planetary, and high-intensity vibrational, for dried-film drug concentration of ~23 wt%. As-received fenofibrate, a model poorly water-soluble drug (~6 µm) was directly mixed with the hydroxypropyl methylcellulose (HPMC) and glycerin aqueous solution. Impeller and planetary mixers yielded desirable film relative standard deviation (RSD), while vibrational mixer could not. For the lowest dried-film drug concentration of ~0.6 wt%, only planetary mixer yielded RSD <6%. The precursor drug homogeneity was a sufficient but not a necessary condition for achieving dried-film RSD <6%. Thus, proper selection of mixer and its CPPs assured desirable film CQAs. However, minor drug particle aggregation was identified via re-dispersion testing which also led to incomplete drug release.