Vesna Savic

The aim of this study was to prepare curcumin/2-hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complex, evaluate the antioxidant and antimicrobial activities of curcumin and curcumin in inclusion complex, as well as to examine the effect of curcumin and curcumin inclusion complex on the textural properties of Carbopol^® gel mixture. Curcumin/2-hydroxypropyl-β-cyclodextrin inclusion complex was prepared using the co-precipitation method in a molar ratio of 1:1. The antioxidant activity of curcumin and curcumin in inclusion complex was determined using DPPH, ABTS, and FRAP methods. The micro-dilution method was used to examine in vitro the antimicrobial activity of curcumin and curcumin in inclusion complex. The textural, rheological, and morphological properties of the samples (Gel 1- Carbopol^® gel; Gel 2- Carbopol^® gel with dispersed curcumin inclusion complex; Gel 3- Carbopol^® gel with dispersed curcumin) were examined. The textural properties were evaluated using a texturometer CT3 Texture Analyzer by means of a Texture Profile Analysis (TPA) test. The results showed that curcumin in inclusion complex had higher antioxidant and antimicrobial activity. The SEM confirms the presence of curcumin and inclusion complex in Carbopol^® gel. The rheological analysis confirmed that the structural integrity of Carbopol^® gel was preserved. The highest swelling degree is achieved by Gel 3 formulation. The in vitro release of curcumin from Gel 2 and Gel 3 occurs at the rates of 0.414 µg/h·g_gel and 0.376 µg/h·g_gel, respectively. The textural analysis showed that adding curcumin or its inclusion complex did not significantly change the properties of Carbopol^® gel, indicating potential for topical use.

Due to the ability to be carriers for both hydrophilic and lipophilic substances, creams as a type of emulsion are extremely popular carriers in the production of pharmaceutical and cosmetic preparations. On the other hand, emulgels, as newer types of emulsions in which the aqueous phase is gelled with gelling agent, are increasingly being investigated. The aim of this study was to examine the differences between textural characteristics and evaluate the stability of emulsion systems stabilized with mixed emulsifier Myristyl Alcohol and Myristyl Glucoside - cream and emulgel whose water phase was gelled with Cellulose gum. Textural analysis was carried out after the preparation of the samples, as well as after one month and after 6 months from the making of the samples. The Brookfield CT3 Texture Analyzer was used to perform texture analysis, for determining the following parameters: hardness cycle 1, hardness cycle 2, adhesiveness, cohesiveness, resilience, and springiness. The results showed that at the beginning of the study, the value of hardness and resilience of cream and emulgel was similar, but the cream had higher cohesiveness and lower adhesiveness and springiness than emulgel. However, during the study, there was a change in the parameters of the emulgel, which were statistically significant during the first month after the production of the emulgel, when an increase in hardness, adhesiveness and springiness appeared. On the repeated measurement after 6 months, there were no significant differences compared to the results after the first month, leading to conclusion that it took less than a month for the emulgel to reach its final structure.

Felt-based dash panel insulation materials have traditionally been used as a sound barrier between the engine and passenger compartments in a vehicle to reduce the transmission of engine noise to the occupant space. Their structural performance has been mainly ignored due to the typically low stiffness and strength characteristics. Consequently, studies of the acoustic properties of these materials have been found in literature while no information was found on their mechanical behavior especially in dynamic loading conditions. More stringent requirements for occupant and pedestrian safety imposed by government regulations and the position of these materials in the impact zones of pedestrian head impact have brought attention to the material contribution to the energy absorption during the impact and the need to assess the mechanical properties of these materials. This paper presents tensile, compressive, and multiaxial impact results from tests conducted on two multi-layered felt-based materials at several different thicknesses and the challenges these soft materials present in tensile testing. Effects of thickness and strain rate on each material are discussed. Finally, a material modeling methodology for each material is proposed and verified by comparison of multiaxial test and simulation results.

Thermoplastics find application in many automotive components. Off late, hardware testing is supplemented by analysis using finite element (FE) codes. One of the factors determining the analysis accuracy is the representation of the components with suitable material models. While a uniaxial tensile test on the specimens typically provides engineering stress-strain data, material plasticity models in commercial FE solvers, such as LS-DYNA and ABAQUS, require equivalent plastic strain versus true stress as input. Engineering stress and strain can be converted to the corresponding true stress and true strain using equations based on the constant volume assumption; however, these equations are valid only up to the point of necking. A conventional approach of estimating the true stress and true strain beyond necking involves a trial and error method in which several true stress-strain curves are generated, and a finite element simulation is used to find the best possible fit with the test data. This approach is time consuming and provides an approximate true stress-strain curve beyond necking. The objective of this paper is to provide an experimental alternative to the conventional approach. Digital image correlation (DIC) was used to measure volumetric strain in the necking region of a tensile test specimen by employing two cameras simultaneously, one focusing on the front (width, length) and the other focusing on the side (thickness, length) surface of the test specimen. True strain measured by DIC in the longitudinal direction and the true stress, estimated from the applied force and measured true transverse strains, were used to generate material models for use in FE analysis without modification, i.e. without a need for correction factors. Material models were then validated by comparing the FE simulation with the tensile test results.

The aim of this study was to compare the stability and texture of three zinc oxide suspensions with different additives. Suspension 1 was made as official magistral formulation Suspensio album 7.5% from Formulae magistrales 2008. Suspension 2 was prepared when 1% carbomer gel was added to suspension 1 and suspension 3 was prepared when polysorbate 20 was added to suspension 2. After stability tests, texture analysis was performed on all suspensions. Following parameters were measured: hardness cycle 1, hardness cycle 2, cohesiveness, adhesiveness, resilience and springiness. The study showed that suspension 3 had the lowest value of hardness, and therefore the best spreadability. Also, suspension 3 was the least sticky of all three, since it was characterized with the lowest adhesiveness. Further, suspension 3 was the most cohesive and is predicted to withstand the stress during packing and use longer than others. On the other hand, the highest values of resilience and springiness were detected for suspension 1, while the lowest was related to suspension 2. Therefore, the best textural characteristics were assigned to suspension 3. This result is in accordance with the results of performed stability tests. The results of our study offer insight into potential improvements of the current magistral formulation Suspensio album 7.5%.

Tensile behavior of advanced high strength steel (AHSS) grades with strengths up to 980 MPa has been extensively studied. However, limited data is found in literature on the tensile behavior of steels with tensile strengths of the order of 1180 MPa, especially at nominal strain rates up to 500/s. This paper examines tensile flow behavior to fracture of four different 1180 MPa grade steels at strain rates of 0.005/s, 0.5/s, 5/s, 50/s and 500/s using an experimental methodology that combines a servo-hydraulic tester and high speed digital image correlation. Even though the strength increase with the strain rate is consistent between the four different materials, the total elongation increase with the strain rate varies widely. Some insights as to why this occurs from examination of the steel microstructure and variation of retained austenite with strain are offered.

In recent years, naturally derived tyrosinase inhibitors and antioxidants have become very important, since the synthetic ones are related with several side effects. As wild fruits are rich source of bioactive compounds, this study focused on the examination of Prunus spinosa L. (blackthorn) fruit extracts, widely distributed in our country. However, blackthorn extracts are not enough investigated, and there are only a few published works. Extraction efficiency of P. spinosa ultrasonic fruit extracts obtained by using different solvents (methanol, 70% (v/v) ethanol, 45% (w/w) propylene glycol and water) was evaluated, regarding polyphenolic profile, tyrosinase inhibitory and antioxidant activity. Results suggested that extracts with 45% propylene glycol and water were particularly rich in polyphenolic compounds (especially phenols, flavonoids and anthocyanins). The highest extraction yield was for 45% propylene glycol extract. This extract showed higher tyrosinase inhibitory and antioxidant activity compared to others, while the methanolic extracts had the highest chelating capacity. Therefore, P. spinosa fruit extracts, especially extracts obtained by ultrasonic extraction with 45% propylene glycol, have a great potential to be incorporated in some pharmaceutical formulations for obtaining tyrosinase inhibitory and antioxidant effects. ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Pessaries with clindamycin phosphate as active component were prepared by moulding. Glycerol-gelatin basis was used as the hydrophilic basis. The pessaries were made with and without the surface-active agent Tween 80 as an excipient. The content of clindamycin phosphate in all samples was determined by high performance liquid chromatography (HPLC) based on the calibration curve of clindamycin phosphate standard solution. The clindamycin phosphate content in the glycerol-gelatin pessaries with or without Tween 80 was optimal. Preparation of extemporaneous (magistral) medicines provides personalization of therapy and the possibility of selection of the most appropriate basis for the specific active substance, which also influences the effectiveness of the therapy. The active substance content in the magistral preparations is not subject to verification in the everyday pharmacy practice. However, by validating the technological process of manufacture and by controlling the quality of the obtained preparations, the choice of the basis in the magistral medicine preparation can be optimized. In this manner, the guidelines for the galenic preparation, including pessaries, can be given to ensure their optimal therapeutic effect.