Diffusion Apparatus Research Articles

Spray Dried Buccal Mucoadhesive Microspheres based on Okra Mucilage: Formulation and In vitro Evaluation

The goal of this work was to create and assess spray-dried buccal mucoadhesive microspheres containing darifenacin Hbr based on okra mucilage. Okra mucilage was used to create the microspheres in various ratios. Several parameters were used to characterize the buccal mucoadhesive microspheres: drug release studies in vitro, ex-vivo mucoadhesive test, swelling test, percentage yield, thermal analysis, scanning electron microscopy, X-ray diffraction, drug incorporation efficiency study, and stability study. In a modified Franz diffusion apparatus, the microspheres were tested for in vitro drug release in a 6.8 phosphate buffer solution for eight hours. The maximum release of 94.65% was displayed. Data was subjected to zero order, first order, Higuchi, and Korsemayers-Peppas models to ascertain the mechanism of release. The in vitro release study's findings indicated that a sustained release was seen. Studies on mucoadhesion have shown a clear relationship between okra mucilage concentration and mucoadhesion. Mucoadhesion and drug incorporation efficiency did not alter, according to the formulation stability analysis.

Revamped mini-αA-crystallin showed improved skin permeation and therapeutic activity against melittin-induced toxicity

Melittin is honey bee venom's primary and most toxic pharmacologically active component. Melittin causes haemolysis, lymphocyte lysis, long-term pain, localised inflammation followed by rhabdomyolysis, and severe renal failure. Renal failure or cardiovascular complications could lead to the victim's death. Severe honey bee bites are treated with general medication involving antihistaminic, anti-inflammatory, and analgesic drugs, as a specific treatment option is unavailable. An earlier study showed the anti-hemolysis and anti-lymphocyte lysis activity of mini- αA-crystallin (MAC), a peptide derived from human eye lens alpha-crystallin. MAC's use has often been restricted despite its high therapeutic potential due to its poor skin permeability. This study compared the skin permeation, anti-inflammatory and analgesic activities of natural peptide MAC and its modified version (MAC-GRD) formed by attaching cell-penetrating peptide (CPP) and GRD amino residues into MAC. Gel formulations were prepared for MAC and MAC-GRD peptides using carbopol (1% w/w), Tween 80 (1%), and ethanol (10%). An ex-vivo skin permeation study was performed using a vertical-type Franz diffusion apparatus. Preclinical in-vivo experiments were conducted to compare the native and modified peptide formulations against melittin-induced toxicity in Wistar rats. MAC gel, MAC–GRD gel and 1% hydrocortisone cream significantly reduced the melittin-induced writhing (20.16 ± 0.792) response in rats with 15.16 ± 0.47, 11.16 ± 0.477 and 12.66 ± 0.66 wriths, respectively. There was a significant reduction in melittin-induced inflammation when MAC-GRD gel was applied immediately after melittin administration. At 0.5, 1, 3, and 5 h, the MAC-GRD-treated rat paws were 0.9 ± 0.043 mm, 0.750 ± 0.037 mm, 0.167 ± 0.0070 mm, and 0.133 ± 0.031 mm thick. Administration of melittin resulted in reduced GSH (antioxidant) levels (47.33 ± 0.760 μg/mg). However, treatment with MAC-GRD gel (71.167 ± 0.601 μg/mg), MAC gel (65.167 ± 1.138 μg/mg), and 1% hydrocortisone (68.33 ± 0.667 μg/mg) significantly increased the antioxidant enzyme levels. MAC-GRD gel significantly reduced the elevated MDA levels (6.933 ± 0.049 nmol/mg) compared to the melittin group (12.533 ± 0.126 nmol/mg), followed by the 1% hydrocortisone (7.367 ± 0.049 nmol/mg) and MAC gel (7.917 ± 0.048 nmol/mg). MAC-GRD demonstrated more skin permeability and superior anti-inflammatory, analgesic, and antioxidant activities when compared to MAC gel. When compared to standard 1% hydrocortisone cream, MAC-GRD had better anti-inflammatory, analgesic, antioxidant, and comparable action in anti-oxidant restoration against melittin. These findings suggest that the developed MAC-GRD gel formulation could help to treat severe cases of honey bee stings.

КИНЕТИКО-ДИНАМИЧЕСКИЕ ПАРАМЕТРЫ ОЧИЩАЮЩЕГО, ПРОТИВОВОСПАЛИТЕЛЬНОГО И РЕМИНЕРАЛИЗИРУЩЕГО ДЕЙСТВИЯ НОВОЙ ЗУБНОЙ ПАСТЫ ПРОТИВ КУРЕНИЯ

Subject. The subject of this study is DentaSwiss Stop Smoking toothpaste.
 Objective. The objective of this study is to define kinetic and dynamic features of cleaning efficacy, remineralizing and anti-inflammatory effects of the new no-smoking toothpaste.
 Methodology. Study participants included 56 volunteers, young patients (26 males, 30 females; the average age of patients was 21.5 ± 1.75 years). The four groups were formed with 14 patients in each group: the first group included smoking patients brushing teeth with DentaSwiss Stop Smoking; the second group included smoking patients brushing teeth with the placebo toothpaste for oral hygiene; the third group included non-smoking patients brushing teeth with DentaSwiss Stop Smoking; the fourth group included non-smoking patients brushing teeth with the placebo toothpaste for oral hygiene. All study participants were evaluated for dental index values and mixed saliva characteristics. Delivery kinetics of DentaSwiss Stop Smoking components containing calcium (KK-component “functional calcite”) was measured using the diffusion apparatus. Diffusion rate in the toothpaste suspension was calculated through cellulose acetate semipermeable membrane. Organoleptic properties of the new toothpaste were evaluated using 10-rating scale survey.
 Conclusions. The diffusion rate of the new toothpaste was 5.0 ± 0.12 pg/s. The average penetration coefficient was 255 ± 0.12 nm/s, the average diffusion coefficient was 10.71 ± 0.08.10-11 m2/s. Toothpaste particle sizes were 2.07 ± 0.17 nm. Studies of use of the new no-smoking toothpaste demonstrated reliable improvement of indices which was evidenced by the increase in pH. On all parameters, organoleptic properties of DentaSwiss Stop Smoking toothpaste were highly ranked by the study participants scoring the average of 9.99 ± 0.01.

Analysis of plant cuticles and their interactions with agrochemical surfactants using a 3D printed diffusion chamber

BackgroundDecades of research is available on their effects of single component surfactant on active ingredient diffusion across plant cuticular membranes, but ingredient diffusion is rarely analysed in the presence of commercial surfactants. Also, diffusion studies require expensive or specialized apparatus the fabrication of which often requires skilled labour and specialized facilities. In this research we have addressed both problems where the effects of four commercially available surfactants on a known tracer molecule were investigated using a 3D printed customized diffusion chamber.ResultsAs a proof-of-concept a customized 3D printed diffusion chamber was devised using two different thermoplastics and was successfully used in a range of diffusion tests . The effect of various solvents and surfactants on S. lycopersicum cuticular membrane indicated an increased rate of flux of tracer molecules across the membranes. This research has validated the application of 3D printing in diffusion sciences and demonstrated the flexibility and potential of this technique.ConclusionsUsing a 3D printed diffusion apparatus, the effect of commercial surfactants on molecular diffusion through isolated plant membranes was studied. Further, we have included here the steps involved in material selection, design, fabrication, and post processing procedures for successful recreation of the chamber. The customizability and rapid production process of the 3D printing demonstrates the power of additive manufacturing in the design and use of customizable labware.

ASSESSMENT OF ADVANTAGES OF USING A DIFFUSION PULSATING APPARATUS FOR RECONSTRUCTION OF THE DIFFUSION SECTION OF A SUGAR FACTORY

The sugar industry in Russia plays a huge role in ensuring the country’s food security and is a strategic industry. Of the 90 sugar factories in Russia today, a third of the factories are closed due to unprofitability associated with the high cost of sugar production due to low feed capacity. The raw material for sugar production is sugar beet, mainly domestically produced. The locations of most sugar factories are small municipalities, for which they are the town-forming enterprises. For the revival of closed sugar factories, it is necessary to increase their capacity, which is difficult to do due to the fact that in the diffusion section of each sugar factory there is one large-sized imported diffusion apparatus of a mechanical type, which does not allow increasing capacity in any other way than purchasing a new, more high-performance expensive imported diffusion apparatus of a mechanical type. In the current conditions of uncertainty and disruption of trade relations with other countries, new suppliers of high-performance diffusion apparatus are needed in Russia itself, the apparatus of which would at least not be inferior to the Western apparatus. The Russian company Ingehim has developed a diffusion pulsating apparatus (DPA) without mechanical movable transporting devices, which reduces energy consumption, operating costs and lowers quality requirements for sugar beet chips. The test results obtained using an experimental unit showed a higher quality of the diffusion juice. The lightness of the juice was found to be much higher compared to juices produced in conventional diffusion apparatus, and the juice purity was found to be 5% higher at a comparable solids content, resulting in an additional amount of sugar produced per year, allowing for a faster return on investment.

Cationic Chitosan/Pectin Polyelectrolyte Nanocapsules of Moxifloxacin as Novel Topical Management System for Bacterial Keratitis

Purpose Moxifloxacin (MOX) is a fourth-generation fluoroquinolone and a broad spectrum antibiotic used in the management of bacterial keratitis (BK). This investigation aimed to formulate MOX-loaded chitosan/pectin cationic polyelectrolyte nanocapsules (CPNCs) for the effective topical treatment of BK. Methods Physicochemical properties like nanocapsule size, charge, drug entrapment efficiency (EE), viscosity, pH, and in-vitro release profile of CPNCs were evaluated. The in-vitro antibacterial activity of CPNCs and marketed formulations (MFs) was studied against Staphylococcus aureus. Ex-vivo corneal permeation studies of CPNCs were evaluated with the help of a modified diffusion apparatus, which was used with goat cornea. The pharmacodynamic study was performed with optimized CPNCs on a BK-induced rabbit eye model and compared with MF. Results The optimized nanocapsules appeared as positive charge (+19.91 ± 0.66) with a nano size (242.0 ± 0.30 nm) as calculated by the dynamic light scattering method. The in-vitro release profile of CPNCs exhibited sustained release properties. The ex-vivo permeation pattern also supported the improved drug permeation through the cornea from CPNCs as compared with MF. Draize irritation studies confirmed that the prepared formulation is compatible with the corneal tissue. The in-vivo study concluded that the antibacterial activity of CPNCs was improved when evaluated with MF. Conclusion The obtained results showed that CPNCs were the better choice for the management of BK therapy due to its capability to improve the corneal adhesion of CPNCs through direct interaction with the mucous membrane of the corneal tissue.

Soil-Gas Diffusivity-Based Characterization of Variably Saturated Agricultural Topsoils

Soil-gas diffusivity and its variation with soil moisture plays a fundamental role in diffusion-controlled migration of climate-impact gases from different terrestrial agroecosystems including cultivated soils and managed pasture systems. The wide contrast in soil texture and structure (e.g., density, soil aggregation) in agriculture topsoils (0–10 cm) makes it challenging for soil-gas diffusivity predictive models to make accurate predictions across different moisture conditions. This study characterized gas diffusivity and gas-phase tortuosity in soils sampled from managed pasture and cultivated sites in Sri Lanka at 0–10 cm depth, together with selected soil-gas diffusivity data from the literature. Soil-gas diffusivity was measured using a one-chamber diffusion apparatus using N2 and O2 as experimental gases. The measured diffusivity, together with literature data representing both intact and repacked soils, were tested against five existing widely known gas diffusivity predictive models. The tested models tended to mischaracterize the two-region behavior in some of the aggregated soils, suggesting the need of soil-specific diffusivity models to better describe gas diffusivity in agricultural soils. We suggested a new parametric two-region model, developed in line with literature-based models, to represent both unimodal and bimodal/two-region behavior of selected soils. The new model statistically outperformed the existing predictive models for both intact and repacked soils and, hence, demonstrated its applicability to better characterize site-specific greenhouse gas emissions under different soil water regimes.

Development and research of a digital control system for juice consumption after the diffusion apparatus in sugar production

The article is devoted to solving the problem of stabilizing the flow rate of diffusion juice at the outlet from the buffer tank under conditions of an unstable hydrodynamic mode of operation of the diffusion apparatus in sugar production. The existing system does not provide effective stabilization of the juice consumption in case of significant fluctuations in the level and situations arise when the buffer tank is empty or overflowed. A digital control system is proposed that improves the dynamic accuracy of juice flow stabilization due to digital correction according to the integral law of setting the flow regulator according to filtered (smoothed) level values and including proportional, differential components in the correction algorithm when the level leaves the “smooth” control area. The effectiveness of the digital control system is confirmed by mathematical modeling in various modes.

Interface interactions in UN-X-UO2 systems (X = V, Nb, Ta, Cr, Mo, W) by pressure-assisted diffusion experiments at 1773 K

UN-UO2 composite fuel is considered an advanced technology fuel (ATF) option to overcome the low oxidation resistance of the UN fuel. However, the interaction between UO2 and UN limits the performance of such composites. A possible way to avoid this interaction is to encapsulate the UN fuel with a material that has a high melting point, high thermal conductivity and reasonably low neutron cross-section. Amongst many candidates, refractory metals can be the first option. In this study, detailed investigations in UN-X-UO2 composite systems (X = V, Nb, Ta, Cr, Mo, W) were performed using SEM/FIB-EDS. The systems were heat-treated at 1773 K and 80 MPa for 10 min in vacuum using the spark plasma sintering method as a pressure-assisted diffusion apparatus. The results suggest that Mo and W are the most promising coating candidates to protect the UN fuel against interactions with UO2. Both metals are inert to N migration and preserve sharp interfaces with the nitride fuel. V, Nb, Ta and Cr strongly interact with UO2 and UN and form their respective nitrides V2N/V8N, Nb2N, and Cr2N. The formation of TaNx was not observed but Ta reacts with UO2 and forms two phases at the UO2-Ta interface (UTa2O7 and Ta2O5), while O from UO2+x diffuses throughout the Ta foil and oxidise the UN pellet via grain boundary attack. This oxidation mechanism also occurs at the V, Nb and Cr-UN interfaces. Our recent atomic scale modelling of the X-UN interfaces also proposes Mo and W as the optimal candidates. Therefore, these results validate the coating candidates for the UN fuel and may guide further experimental/modelling development in UN-X-UO2 advanced technology fuel.

Formulation and Evaluation of Microemulsion of Curcumin in Thymol-Menthol Carrier System

Aim: To formulate and evaluate the Micro emulsion of curcumin in thymol-menthol carrier system.
 Study Design: Curcumin dissolves in mixture of thymol & menthol to reasonable extent.100 mg of curcumin in 1 g of thymol and 0.6 g of menthol mixture was finalized as product mixture. The solution of curcumin in eutectic mixture being oily liquid, it gave the idea for development for the micro emulsion
 Place and Duration of Study: Department of Pharmaceutics and Department of Pharmacognosy, STES’s Smt. Kashibai Navale College of Pharmacy, Kondhwa (BK), National Chemical Laboratory, Pune between June 2016 and May 2017.
 Methodology: Micro emulsion system with eutectic mixture of thymol and menthol was chosen as oil phase and carrier for curcumin, tween 80 as surfactant and ethanol as co-surfactant. Ternary phase diagrams were constructed to obtain the optimum concentration range of oil phase, surfactant and co-surfactant. The micro emulsion of 100 mg curcumin containing 4.95 % oil phase, 33.39 % surfactant, 11.13% co-surfactant, 50:50% of water was optimum. Micro emulsion of curcumin was prepared by water titration method and evaluated for globule size, drug content, pH, viscosity, conductivity and In vitro drug release study. The ex-vivo permeation study for micro emulsion of curcumin was carried out on excised mice skin using Franz Diffusion apparatus. The cytotoxicity study for thymol, menthol was performed on healthy L929 murine fibroblast cell line. Anticancer activity of thymol-menthol eutectic mixture alone and with curcumin was performed on HeLa cell lines.
 Results: The preformulation studies did clearly indicate good compatibility of drug with thymol menthol carrier system. The cytotoxicity study was done on thymol – menthol(TM) as a preformulation aspect to ascertain the toxicity of these two excipients to be tried. It was found that TM was not cytotoxic in 120ug/mL concentration and thus was safe to be used in concentration below 120ug/mL. Batch B1 was optimised. The average globule size of micro emulsion was found to be 131.54 nm, zeta potential was found to be -0.57 mV. The drug content in micro emulsion batch B1 was determined and found to be 74.6%.Permeability study across mice skin ex-vivo model showed 52.38% permeability compared with curcumin alone which was 22.41%. So permeability of curcumin is enhanced substantially with micro emulsion made in thymol and menthol, owing to fact that thymol and menthol act as good permeation enhancers. The In vitro drug release study of micro emulsion was compared with curcumin alone. About 48.75% of curcumin was released from micro emulsion showed increase in release rate.
 Conclusion: Eutectic mixture of thymol and menthol showed promising results as penetration and solubility enhancer for curcumin. Solubility of curcumin was improved so as its rate of permeation which was used to develop formulation of micro emulsion with proven anticancer activity. The solubility of curcumin formulated with combination of eutectic mixture was increased up to 50 %.

Pharmacokinetic interactions: The effects of selected herbal extracts on permeation of P-glycoprotein substrate drugs across excised pig intestinal tissue

Introduction: There is growing concern that co-administered herbal medicines may alter the pharmacokinetics and, therefore, the efficacy and toxicity of Western drugs. The aim of this study was to investigate the potential membrane permeation modulating effects of four herbal extracts, i.e., Harpagophytum procumbens, Hoodia gordonii, Leonotis leonurus, and Vitis vinifera on a model compound, Rhodamine 123 (RH-123). Methods: An in vitro permeation model, i.e., excised pig intestinal tissue, mounted to test chambers in a Sweetana-Grass diffusion apparatus, was used to measure the bi-directional transport of RH-123 in the presence and in the absence of four herbal extracts. The concentration of transported RH-123 in each sample was determined by means of fluorescence spectroscopic analysis. The integrity of the mounted jejunum tissue during experimentation was confirmed by measuring the permeation of Lucifer Yellow through these membranes. Trans-epithelial electrical resistance (TEER) of the mounted membranes was also measured at the onset and termination of each experiment to monitor whether tight junction modulation occurred. Results: H. procumbens extract increased the secretory transport of RH-123, indicative of the induction of P-glycoprotein (P-gp) mediated efflux. H. gordonii extract also increased RH-123’s absorptive transport, coupled with a subsequent decrease in its secretory transport, indicating the P-gp related efflux inhibition. Contrary, L. leonurus extract reduced RH-123’s absorptive transport, accompanied by an increase in its secretory transport. V. vinifera seed extract, however, increased both the absorptive and secretory transport of RH-123. A reduction in TEER was observed in the presence of V. vinifera extract, indicating the modulation of tight junction integrity. Conclusion: The ex vivo pharmacokinetics interactions recorded in the current study suggest that the co-administration of herbal medicines could alter the extent of membrane permeation of Western drugs.

Comparison of physical enhancement technologies in the skin permeation of methyl amino levulinic acid (mALA)

Physical drug delivery enhancement in skin has been shown to enhance cosmeceutical actives efficacy. Among the physical drug delivery enhancement technologies, microneedle is the most commercially successful technology. However, there are pros and cons like other physical enhancement technologies including variabilities in penetration depth and lack of efficacy. In this study, three physical topical dug delivery enhancements, elongated microparticles, microneedles and dermaroller, were applied to ex vivo pig skin and compared. The model topical drug that was used is 5-Aminolevulinic acid, the most commonly used photosensitiser prodrug. The skin was pre-treated before mounting on to Franz cell diffusion apparatus. Transdermal epidermal water loss was measured, and receptor fluids were collected at 7 time points for HPLC analysis. The results show that all three technologies disrupted the skin surface. All microporation pre-treatments significantly enhanced mALA cumulative permeation over 8 h (p < 0.001), with the 24x dermaroller significantly greater than 12x dermaroller (p < 0.001) and both dermaroller treatments significantly greater than microneedles and elongated microparticles (p < 0.05). The microporation pre-treatments all significantly increased mALA deposition in the stratum corneum and deeper skin tissues compared to passive administration, with deposition increases ranging from 3.6x to 15.1x that of passive administration. The DR pretreatment showed highest enhancement ratios (amount 5-Aminolevulinic acid in skin at 8 h following pretreatment v passive) with the following order of enhancement: 24x dermaroller > 12x dermaroller > microneedles > elongated microparticles. In conclusion, physical enhancement tools such as microneedles, dermarollers and elongated microparticles demonstrated significant penetration and retention of mALA through/into piglet skin. Further study is needed to determine the cost, dose and patient compliance.

Effects of Transport Medium Composition on In vitro Drug Permeation Across Excised Pig Intestinal Tissue

Background:: Knowledge of the permeation characteristics of new chemical entities across biological membranes is essential to drug research and development. Transport medium composition may affect the absorption of compounds during in vitro drug transport testing. To preserve the predictive values of screening tests, the possible influence of transport media on the solubility of model drugs and on the activities of tight junctions and efflux transporter proteins (e.g., Pglycoprotein) must be known. Objective:: The aim of this study was to compare the impact of different transport media on the bidirectional transport of standard compounds, selected from the four classes of the Biopharmaceutical Classification System (BCS), across excised pig intestinal tissue. Methods:: The Sweetana-Grass diffusion apparatus was used for transport studies. Krebs-Ringer bicarbonate (KRB) buffer and simulated intestinal fluids in the fed (FeSSIF) and fasted (FaSSIF) states were used as the three transport media, while the chosen compounds were abacavir (BCS class 1), dapsone (BCS class 2), lamivudine (BCS class 3) and furosemide (BCS class 4). Results:: Abacavir exhibited lower permeability in both the simulated intestinal fluids than in the KRB buffer. Dapsone showed similar permeability in all media. Lamivudine exhibited lower permeability in FaSSIF than in the other two media. Furosemide exhibited improved transport with pronounced efflux in FaSSIF. Conclusion:: Different permeation behaviors were observed for the selected drugs in the respective media, which may have resulted from their different physico-chemical properties, as well as from the effects that dissimilar transport media components had on excised pig intestinal tissue.

Formulation and Evaluation of Lawsone Loaded Nanosponge Gel for Topical Delivery

The target of the current report considers producing controlled-release lawsone-loaded nanosponge gel for topical delivery. Lawsone is also known as hennotannic acid, is an active pharmaceutical agent found in the general leaves of the henna plant responsible for an antifungal agent to treat cutaneous candidiasis. The current nanosponge formulation is carried out using ethyl cellulose as polymer, polyvinyl alcohol as co-polymer dichloromethane as a cross-linker & propylene glycol as a permeation enhancer. The formulation was prepared through emulsion solvent diffusion approach as well as the prepared nanosponge gels were evaluated by physical appearance, determination of PH, spreadability, extrudability, skin irritation test, drug content, entrapment efficiency, and in-vitro diffusion studies. The physical appearance of the LNS1 & LNS7 formulation was watery and the remaining formulations were found to have smooth, transparent, homogenous with a gel-like consistency. The PH of formulated nanosponge gel formulation was found to be in the range between 4.5-5.5. It was concluded that all the PH values within the range of skin PH. The spreadability values ranging from 7.2-8.5. In the formulations (LNS1 & LNS8) far more than 90% going from contents had been extrudable indicating they need perfect extrudability with the except for LNS1 & LNS7 as 80% of the contents were extrudable. The skin irritation test of lawsone loaded nanosponge gels (LNS1-LSN5) had been strain irritation at a site of application. The drug content ranging from 79-92.2% & entrapment efficiency ranging from 66-80% was obtained. In-vitro drug diffusion research had been performed by diffusion apparatus containing 100ml PH 5.0 phosphate buffer maintained at 37 oC. LNS6 was found to show a drug release of 68.8%. Therefore LNS6 formulation sustained the drug release and was considered as optimized formulation over LNS4-LSN7. The ‘n’ value of formulation LNS6 was 0.899and suggesting drug was released by Zero-order kinetics.

Strength of Shell Structure Operating in Hydrogenous Media under Pressure

Estimation of strength and durability of any structure can be carried out after finding components of stress-strain state of all its parts. The present work shows that in order to calculate stresses in a certain element of a structure that works under thermo-mechanical loading and contacts hydrogenous media, one should trace distribution of heat and hydrogen concentration in this element. Based on the results obtained when having solved thermo-diffusion problem of heat and hydrogen distribution in a casing of a diffusion apparatus, its stress state was found. Casing of the diffusion apparatus is represented in a shape of a shell of revolution. It was determined that in a thin shell, homogenous fields of temperature and hydrogen concentration are being set for a period that is significantly less than the design operating life of the apparatus. To solve the problem of stress distribution in a shell, S.K. Godunov’s method of discrete orthogonalization was used. In the structure that does not have any manifested stress raisers, a critical point with maximum value of shear stress intensity was found. Consistent patterns of change of the intensity in the critical point were found under the emergency pressure boost in the apparatus at various hydrogen densities. The paper shows that emergency pressure boost in a shell may cause the appearance of zones of plastic yield; when this boost is accompanied by increase in hydrogen concentration, the fracture pattern changes from viscous to brittle.

Автоматизований контроль механічних параметрів дводвигунового електропривода похилого дифузійного апарата

The article is devoted to the mechanical parameters automated control method development. Control object is the two-engine electric drive of an inclined diffusion apparatus. It is shown that in production conditions, the traditional automated control system, equipped with only electrical parameters control system, does not meet the requirements for the reliability of the two-engine electric drive with elastic bonds in the kinematic circuit. Structural schemes of two-motor electric drive`s relative rotation angle and speed control methods are developed. Theoretical evaluation of metrological characteristics of the proposed measuring channels was carried out, its static characteristics were constructed, and quantization errors were determined. It was established that the quantization error of the measuring channel is directly proportional to the mark number of engine shaft rotation sensors. Therefore, the optimal number of marks for means of mechanical parameters control was determined, which would ensure the necessary reliability of control. The algorithms of two-motor electric drive`s relative rotation angle and speed automated control are developed, the production implementation results of developed control means based on theoretical research are presented. Experimental studies of the two-motor electric drive`s relative rotation angle and speed automated control work, which showed the complete adequacy of measurement, both the speed of engines rotation and their shafts relative rotation angle, were carried out. The real metrological characteristics of these means correlate with theoretical developments. With the help of developed control means, experimental time charts were obtained that illustrate the operation of an inclined diffusion apparatus two-engine electric drive, in transient gear modes associated with the presence of an elastic-dissipative connection between the drive engines and the uneven distribution of torque between them. Preliminary theoretical studies of the dynamic properties of such an electric drive system have been experimentally confirmed.

A comparative study of the release of active ingredients from semisolid cosmeceuticals measured with Franz, enhancer or flow-through cell diffusion apparatus

This study reports the release properties of the poorly water-soluble drug hydrocortisone, antibacterial agent triclosan, and the water-soluble anti-aging compounds salicylic acid and ascorbic acid from gels, creams, and ointments, alone or combined with triclosan. Drug release was measured with the flow-through, Franz, and Enhancer cell release testing methods. For the 3 methods, a cellulose acetate membrane soaked in lipophilic oleic acid and dissolution mediums composed of a phosphate buffer pH 5.8 or a 50% ethanol: buffer mixture gave more constant and less variable release profiles (similarity factors, f2, above 50). Comparison of the release rates of hydrocortisone, salicylic acid, ascorbic acid, and triclosan from creams and gels showed that the rates measured with the flow-through cells were significantly slower (p < 0.01) than those measured with the Franz and Enhancer cells. In all 3 systems, hydrophilic compounds released faster in the buffer solution and from the gels. Less water-soluble compounds and lipophilic compounds released faster in the hydro-alcohol mixture and from creams and ointments. The disadvantages of the flow-through cells were difficult operation and small sample sizes which caused variable results. The advantages of the Enhancer cells were that they used the basic USP dissolution apparatus and had a larger volume range making it easier to adapt the system for studying the release of products containing low concentrations of active ingredients or ingredients that are difficult to analyze.

Application of synthetic membranes in establishing bio-predictive IVPT for testosterone transdermal gel.

The current study investigated the use of synthetic membranes in developing a bio-predictive in vitro permeation testing (IVPT) method for 1.62% testosterone gel. The IVPT studies were carried out using both Franz (FC), and Flow-through (FTC) diffusion cells. The experimental variables included the type of synthetic membranes (hydrophilic polyamide nylon, polysulfone tuffryn and STRAT-M (SM) membrane) and the type of receiver media (phosphate buffer containing various concentrations of sodium lauryl sulfate). In vivo drug release rates were obtained from published reports for 1.62% testosterone gel applied to either abdominal area (treatment group A), upper arms/shoulders (treatment group B), or alternating between abdomen and arms/shoulders (treatment group C). The in vitro-in vivo correlations were established using GastroPlus software. The best IVPT method was selected based on establishing point-to-point correlation with the in vivo data of treatment group A with minimal prediction errors (%PE) of AUC0-24 and Cmax. The results showed that the IVPT method which employed the FTC diffusion system, SM membrane and phosphate buffer without surfactant established the best IVIVR model with a correlation coefficient (R2) of 0.9966 and an exponential function of Y=(1.35)5×X3.6. The in vivo data obtained from treatment group A and B was used for internal validation of the prediction model. The validation data was acceptable, with %PE of less than 10% for both AUC0-24 and Cmax. In conclusion, these results suggest that bio-predictive IVPT methods for testosterone gels may be developed using synthetic membranes and diffusion apparatus by varying the composition of the receiver medium.

ESTIMATION OF THE SUITABILITY OF METHODS FOR DETERMINING LACTIC ACID CONTENT IN DIFFUSION JUICE FOR APPLICATION IN CHEMICAL AND TECHNICAL CONTROL OF SUGAR PRODUCTION

Development of microbiological infection in the process of production of diffusion juice is one of the most important factors affecting the quality of diffusion juice and sucrose loss. In this regard, it is important to promptly monitor the microbiological contamination of mixture from water and beet chips in the diffusion apparatus. Lactic acid is used as an indicator of the degree of microbiological contamination of the diffusion juice. Traditionally, when calculating unaccounted sucrose losses on diffusion, the titrimetric method is used to determine the concentration of lactic acid with preliminary isolation of acid anions from the diffusion juice on ionite columns. However, this method is time-consuming and labor-intensive and is not suiTable for operational control. The article suggests using a simpler and less time-consuming spectrophotometric method for operational control, based on measuring the optical density of the colored product of the reaction of lactate ions with iron(III) chloride at a wavelength 400 nm. The results of evaluating the consistency of data on the content of lactic acid in diffusion juices obtained using the traditional and spectrophotometric methods are presented in article. The results of data analysis using the Bland-Altman descriptive statistics method confirm that the data obtained by various methods are in good agreement with each other, and therefore the spectrophotometric method for determining the concentration of lactate ions can be used in production control in the sugar industry.

Effective diffusivity of oxygen in the ash layer of Huadian oil shale semicoke

Diffusion of oxygen in the ash layer usually dominated the combustion of oil shale semicoke particles due to the high ash content. Thus, effective diffusivity of oxygen in the ash layer was a crucial parameter worthy of careful investigation. In this paper, the effective diffusivity of oxygen in the ash layer of Huadian oil shale semicoke was measured directly using an improved Wicke-Kallenbach diffusion apparatus. The experimental results showed that higher temperature would lead to a higher effective diffusivity and a thicker ash layer had the negative effect. Especially, the effective diffusivity along the direction perpendicular to bedding planes was much lower than that along the direction parallel to bedding planes. In addition, an effective diffusivity model was developed, which could be used to describe the mass transfer of oxygen in the ash layer of oil shale semicoke.