Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

The present work aimed at assessing the pharmaceutical tableting properties of some Egyptian kaolin samples belong to the Abu Zenima kaolin deposits (estimated at 120 million tons). Four representative samples were selected based on kaolinite richness and their structural order-disorder degree, and after purification, they were dried at 70 ºC and heated from room temperature up to 400 ºC (10 ºC/min). Mineralogy, micromorphology, microtexture, granulometry, porosimetry, moisture content, bulk and tapped density, direct and indirect flowability, and tableting characteristics are studied. Results indicated that purified kaolin samples were made up of 95–99% kaolinite, <3% illite, 1% quartz and 1% anatase. The powder showed mesoporous character (pore diameters from 2 to 38 nm and total pore volume from 0.064 to 0.136 cm3/g) with dominance of fine nanosized particles (<1 um–10 nm). The powder flow characteristics of both the ordered (Hinckley Index HI > 0.7, crystallite size D001 > 30 nm) and disordered (HI < 0.7, D001 < 30 nm) kaolinite-rich samples have been improved (Hausner ratio between 1.24 and 1.09) as their densities were influenced by thermal treatment (with some observed changes in the kaolinite XRD reflection profiles) and by moisture content (variable between 2.98% and 5.82%). The obtained tablets exhibited hardness between 33 and 44 N only from the dehydrated powders at 400 ºC, with elastic recovery (ER) between 21.74% and 25.61%, ejection stress (ES) between 7.85 and 11.45 MPa and tensile fracture stress (TFS) between 1.85 and 2.32 MPa, which are strongly correlated with crystallinity (HI) and flowability (HR) parameters. These findings on quality indicators showed the promising pharmaceutical tabletability of the studied Egyptian kaolin powders and the optimization factors for their manufacturability and compactability.This work has been funded by the Egyptian Cultural Affairs and Missions Sector (Plan 2013–2014), Ministry of Higher Education, in collaboration with the Group CTS-946 (Junta de Andalucía) and MINECO project CGL2016-80833-R (Spain), and the grant funded by Erasmus+ KA1 mobility program 2016/2017

Comparative assessment of in vitro and in silico methods for aerodynamic characterization of powders for inhalation

In vitro assessment of dry powders for inhalation (DPIs) aerodynamic performance is an inevitable test in DPI development. However, contemporary trends in drug development also implicate the use of in silico methods, e.g., computational fluid dynamics (CFD) coupled with discrete phase modeling (DPM). The aim of this study was to compare the designed CFD-DPM outcomes with the results of three in vitro methods for aerodynamic assessment of solid lipid microparticle DPIs. The model was able to simulate particle-to-wall sticking and estimate fractions of particles that stick or bounce off the inhaler’s wall; however, we observed notable differences between the in silico and in vitro results. The predicted emitted fractions (EFs) were comparable to the in vitro determined EFs, whereas the predicted fine particle fractions (FPFs) were generally lower than the corresponding in vitro values. In addition, CFD-DPM predicted higher mass median aerodynamic diameter (MMAD) in comparison to the in vitro values. The outcomes of different in vitro methods also diverged, implying that these methods are not interchangeable. Overall, our results support the utility of CFD-DPM in the DPI development, but highlight the need for additional improvements in these models to capture all the key processes influencing aerodynamic performance of specific DPIs

Optimization of technological procedure for amygdalin isolation from plum seeds (Pruni domesticae semen)

The process of amygdalin extraction from plum seeds was optimized using central composite design (CCD) and multilayer perceptron (MLP). The effect of time, ethanol concentration, solid-to-liquid ratio, and temperature on the amygdalin content in the extracts was estimated using both mathematical models. The MLP 4-3-1 with exponential function in hidden layer and linear function in output layer was used for describing the extraction process. MLP model was more superior compared with CCD model due to better prediction ability. According to MLP model, the suggested optimal conditions are: time of 120 min, 100% (v/v) ethanol, solid-to liquid ratio of 1:25 (m/v) and temperature of 34.4 degrees C. The predicted value of amygdalin content in the dried extract (25.42 g per 100 g) at these conditions was experimentally confirmed (25.30 g per 100 g of dried extract). Amygdalin (>90%) was isolated from the complex extraction mixture and structurally characterized by FT-IR, UV, and MS methods

Current Mathematical Methods Used in QSAR/QSPR Studies

This paper gives an overview of the mathematical methods currently used in quantitative structure-activity/property relationship (QASR/QSPR) studies. Recently, the mathematical methods applied to the regression of QASR/QSPR models are developing very fast, and new methods, such as Gene Expression Programming (GEP), Project Pursuit Regression (PPR) and Local Lazy Regression (LLR) have appeared on the QASR/QSPR stage. At the same time, the earlier methods, including Multiple Linear Regression (MLR), Partial Least Squares (PLS), Neural Networks (NN), Support Vector Machine (SVM) and so on, are being upgraded to improve their performance in QASR/QSPR studies. These new and upgraded methods and algorithms are described in detail, and their advantages and disadvantages are evaluated and discussed, to show their application potential in QASR/QSPR studies in the future

Dworkin und Aristoteles - über die Ungerechtigkeit : führt der Fokus auf die Ungerechtigkeit zu «gerechteren» Gerechtigkeitstheorien?

Im Zentrum steht die Frage nach der Ungerechtigkeit, die der Mensch im Alltag einer Gesellschaft und eines Staates erfahren kann, und inwieweit diese Erfahrung die Theorie einer Gerechtigkeitslehre nachhaltig prägen konnte. Die Dissertation untersucht das aristotelische und dworkinsche Begriffsverständnis der Ungerechtigkeit und setzt sich mit rechtlichen und politischen Fragestellungen auseinander, indem die Ungerechtigkeit und die Gerechtigkeit in Zielkonflikten von Freiheits- und Gleichheitsrechten, die Bildung demokratischer Prozesse und im Verhältnis mit Unrecht untersucht wird. Zudem widmet sich die Dissertation der Frage, ob die Ungerechtigkeit bloss eine Negation der Gerechtigkeit ist und lediglich als Startpunkt in der Gerechtigkeitsdiskussion dient

Ronald Dworkin: Seeking Truth and Justice through Responsibility

According to Dworkin, “truth” is an interpretative concept. Why? Moral judgements are often the subject of disagreement because they are often the result of divergent conceptual understandings. If, on the other hand, we want to interpret concepts correctly, we have to deal with the analysis of the underlying values we attach to these concepts. Dworkin understands the true as a matter of interpretation, which—and this is often misunderstood—is capable of producing a correct conception of the truth. The truth is thereby directly related to justice. Dworkin even ties his theory of interpretation to an objective truth that can only produce conclusive reasons for a specific advocacy of a particular position in an argument after responsible and intensive debate—in the sense of his two-stage theory. In fact, it turns out that Dworkin’s search for and conception of an objective truth describes a (historical) process. We interpret what our ancestors have already interpreted and continue to understand (in a modified way). This reflexive responsibility is ours to bear; according to Dworkin, it is our responsibility to always stand up for truth through good arguments

IMPLANT-PROSTHETIC REHABILITATION OF UNIDENTARE EDENTATION – PRINCIPLES OF TREATMENT

For a practitioner with experience, the restoration with one or two individual crowns is relatively simple from clinical and technical point of view, but if a single crown has to be rebuilt in areas with major aesthetic concern, the prosthetic restoration becomes a challenge for any team of professionals. A major challenge for such a team si the unidental restoration, with or without implants, of a single incisor from the frontal maxillar area, especially the central superior incisors. These teeth have a highly aesthetic part since they are in direct connection with the shape and the aspect of the face. In the evaluation of the dental shape of the central incisors we can use different parameters which are closely related to the individual anatomical aspects of each patient: the shape and aspect of the face, the analysis of the existing casts or photos from the youth of the patient with the natural teeth. Finally, the decision is taken together with the patient after we establish the expectations and his possible personal demanding. By comparison with the frontal area, the restoration of the posterior teeth presents some advantages: •The width of the initial alveolar crest is greater in the posterior area next to the frontal one; •The vestibular wall is denser and more extensive and allows the 4-5mm implant placement; • The esthetic aspect of the cervical area of the posterior teeth including the interdental spaces and the gingival papilae are less demanding than the frontal esthetical regions; •The esthetics of the shape of the crowns, the emerging profile of the crowns as well as the colour shades are less pretentious; •The placement of an implant in a unidental lateral space spares the practitioner of the preparation of the neighbouring teeth to the edentulous space, resulting a few advantages. We should not forget that, through the increasingly modern methods of mass media spreading, the patient is more curious and informed, consequently more demanding. All these requirements must be weight and if achievable, they will be analysed by the medical team then discussed with the patient

Evaluation of diclofenac sodium release from matrix pellets compressed into MUPS tablets

The purpose of the study was to screen the effects of formulation factors on the in vitro release profile of diclofenac sodium from matrix pellets compressed into multiple unit pellet system (MUPS) tablets using design of experiment (DOE). Extended release of diclofenac sodium was accomplished using Carbopol 71G as matrix substance. According to Fractional Factorial Design FFD 2(3-1) four formulations of diclofenac sodium MUPS matrix tablets were prepared. The process of direct pelletization and subsequently compression of the pellets into tablets was applied in order to investigate a different approach in formulation of matrix systems and to achieve a better control of the process factors over the principal response - the release of the drug. The investigated factors were X1-the percentage of polymer Carbopol 71G, X2-crushing strength of the tablet and X3-different batches of the diclofenac sodium. In vitro dissolution time profiles at 6 different sampling times were chosen as responses. Results of drug release studies indicated that drug release rates vary between different formulations, with a range of 1 to 8 h to complete dissolution. The most important impact on the drug release had factor X1-the percentage of polymer Carbopol 71G. The polymer percentage is suggested as release regulator for diclofenac sodium release from MUPS matrix tablets. All other investigated factors had no significant influence on the release profile of diclofenac sodium