Fizikokemijska karakterizacija čvrstih disperzijskih sustava tadalafila s poloksamerom 407

Dissolution behaviour of a poorly water-soluble drug, tadalafil, from its solid dispersion systems with poloxamer 407 has been investigated. Solid dispersion systems of tadalafil were prepared with poloxamer 407 in 1:0.5, 1:1.5 and 1:2.5 ratios using the melting method. Characterization of binary systems with FTIR and powder XRPD studies demonstrated the presence of strong hydrogen bonding interactions, a significant decrease in crystallinity and the possibility of existence of amorphous entities of the drug. In the binary systems tested, 1:0.5 proportion of tadalafil/poloxamer 407 showed rapid dissolution of tadalafil (DE30 70.9 ± 3.6 %). In contrast, higher proportions of poloxamer 407 (1:1.5 and 1:2.5) offered no advantage towards dissolution enhancement of the drug from corresponding binary systems indicating altered rheological characteristics of the polymer, at its higher concentration, which might have retarded the release rate of tadalafil.U radu je ispitivano oslobađanje u vodi teško topljivog lijeka tadalafila iz čvrstih disperzijskih sustava. Ti sustavi pripravljeni su s poloksamerom 407 u omjeru lijeka i polimera 1:0,5, 1:1,5 i 1:2,5, koristeći metodu taljenja. Karakterizacija binarnih sustava s FTIR i rendgenskom difrakcijom praha XRD ukazuje na prisutnost snažnih vodikovih veza, značajno smanjenje kristaliničnosti i moguću prisutnost amorfnog lijeka. Iz binarnog sustava tadalafil/poloksamer 1:0,5 oslobađanje ljekovite tvari je brzo (DE30 70,9 ± 3,6 %). Nasuprot tome, iz pripravaka s višim omjerima lijeka i polimera (1:1,5 i 1:2,5) oslobađanje ljekovite tvari nije povećano. Usporavanje oslobađanja tadalafila moglo bi biti posljedicom promjene reoloških svojstava polimera pri višim koncentracijama

Neural Correlates of Visual Motion Prediction

Predicting the trajectories of moving objects in our surroundings is important for many life scenarios, such as driving, walking, reaching, hunting and combat. We determined human subjects’ performance and task-related brain activity in a motion trajectory prediction task. The task required spatial and motion working memory as well as the ability to extrapolate motion information in time to predict future object locations. We showed that the neural circuits associated with motion prediction included frontal, parietal and insular cortex, as well as the thalamus and the visual cortex. Interestingly, deactivation of many of these regions seemed to be more closely related to task performance. The differential activity during motion prediction vs. direct observation was also correlated with task performance. The neural networks involved in our visual motion prediction task are significantly different from those that underlie visual motion memory and imagery. Our results set the stage for the examination of the effects of deficiencies in these networks, such as those caused by aging and mental disorders, on visual motion prediction and its consequences on mobility related daily activities

Divorce Trends in Seven Countries Over the Long Transition from State Socialism: 1981–2004

The collapse of communism was a defining geopolitical event of late-20th century Europe, with well-documented economic, social, and political implications. Yet there is a striking absence of research on how it influenced divorce. The objective of this study is to provide an exploratory analysis of trends in divorce over the long transition from communism—starting from the decline of the communist economy in the 1980s and ending with economic revival—in seven countries: Bulgaria, Estonia, Hungary, Lithuania, Poland, Romania, and Russia. We discuss how the transition could be expected to either increase or decrease divorce risks. We analyze retrospective micro-level data on first marriages from the Changing Life Course Regimes in Eastern Europe (CLiCR) dataset. Based on our event-history analyses, we find that divorce rates increased in each country at some stage during the long transition and these increases cannot be explained by compositional change of the marriages. However, no uniform pattern emerged in the timing and duration of the increase in divorce risk. This striking variation leads us to conclude that even the effect of major societal ruptures is contextually contingent