553 research outputs found
DESAFIOS DO FINANCIAMENTO PÚBLICO DAS UNIVERSIDADES ESTADUAIS BAIANAS
O presente trabalho aborda o tema da política de financiamento da educação superior no Estado da Bahia, no que diz respeito às Universidades Estaduais Baianas (UEBAs), em especial à Universidade Estadual de Feira de Santana (UEFS). Este trabalho apresenta resultados preliminares de estudos exploratórios, bibliográficos e documentais, com o objetivo de investigar como se caracterizou a política de financiamento da UEFS, no período de 2005 a 2014, diante de um quadro de dificuldades e limitações orçamentário-financeiras. Este estudo realiza uma análise descritiva da situação orçamentário-financeira e procura descrever os desafios e obstáculos enfrentados por essa instituição. Os resultados evidenciam um cenário desafiador para as UEBAs, em relação ao financiamento, oferta e expansão de educação superior no Estado da Bahia, marcado pelo nível de concentração orçamentária das despesas de pessoal e encargos; reduções orçamentárias na cota inicial para custeio e investimentos em relação aos exercícios anteriores; além de interferências na autonomia administrativa e na gestão financeira da universidade. O estudo ainda propõe reflexões sobre possíveis caminhos e ações propositivas para o financiamento, fortalecimento e sustentabilidade financeira das UEBAs
Pure solvent solubility of some pharmaceutical molecules
During the search for novel or improved therapies, new drugs are proposed. Solubility of drug-candidates is important both for drug production and its therapeutic use. Many separation processes in the pharmaceutical industry are based on the solubilities in different solvents. Solvation plays an important role in the organism in each stage of drug transport and delivery. Properties like lipophilicity, hydrophilicity, the ability to establish hydrogen bonds and other interactions of the molecules with the surrounding media play an important role in the solvation process. Although some predictive thermodynamic tools can be used to determine drug solubility, the availability of experimental data is still fundamental for an appropriate model development and evaluation.
In this work, solubilities of some drugs, such as paracetamol, budesonide, furosemide and allopurinol, were measured in the temperature range between 25 °C and 42 °C, in pure solvents (water, ethanol, acetone, n-hexane, ethyl acetate and carbon tetrachloride). The Non-random Two-Liquid Segment Activity Coefficient (NRTL-SAC) equation (Chen and Song 2004), one of the most successful models for the representation of drug solubility, was used to model the data. The obtained agreement is very satisfactory (root mean square deviation of 0.051)
Aqueous solubility of some natural phenolic compounds
In this work, the aqueous solubilities of two hydroxybenzoic acids (gallic and salicylic acid) and three
phenylpropenoic acids (trans-cinnamic, ferulic, and caffeic acids) are addressed. Measurements were performed,
as a function of temperature, between 288.15 and 323.15 K, using the shake-flask method for generating the
saturated aqueous solutions, followed by compositional analysis by spectrophotometric and gravimetric methods.
The pH values of the saturated aqueous solutions were measured by potentiometry. Additional thermodynamic
properties, which are fundamental for a better understanding of the solubilization process, as well as necessary
for the modeling studies, such as melting temperatures and fusion enthalpies were determined by differential
scanning calorimetry (DSC). Apparent acid dissociation constants (Ka) were obtained by potentiometry titration.
The measured data were modeled with the cubic-plus-association (CPA) equation of state (EoS). This EoS is
applied, for the first time, for multifunctional associating molecules, and the results indicate that it can adequately
be used to represent the measured and other literature data with satisfactory accuracy
Temperature and solvent effects in the solubility of some drugs: experimental and modeling
New drugs are always appearing during the development of new therapies or
the improvement of existing ones. The effects of these drugs in the organism
are dependent on the techniques used by the pharmaceutical industry to make
them more soluble [1]. Solubility data involving new drug candidates are
frequently not available in the open literature and, although predictive
thermodynamic models can be used, the availability of experimental data is still
fundamental for an appropriate model development and evaluation. One of the
most recent and successful models is the Nonrandom Two Liquid Segment
Activity Coefficient (NRTL-SAC) model [2-5], which gives reasonable results in
the prediction of drug solubilities and has been widely applied to correlate and
predict phase equilibria of highly nonideal systems, both in pure and mixed
systems, both at academic and industrial level
Comparing approaches for drug-like molecules solubility calculations
Solubility has been recognized as one of the most important properties for designing separation and purification processes of complex molecules, such as active pharmaceutical ingredients. Experimental solubility data are usually needed for performing such design operations. However, frequently data are unavailable due to reduced amounts of sample, time limitations, or inherent complexities with experimental measurements. In such cases, thermodynamic models can be the more theoretically sound tools to generate solubility estimates.
In this work, the group-contribution method UNIFAC, and the NRTL-SAC activity coefficient model, are used to correlate and predict solubility in pure and mixed solvents of a set of representative drug-like molecules such as benzoic, salicylic and acetylsalicylic acids, ibuprofen, hydroquinone, estriol, estradiol and resveratrol. Generally, UNIFAC and NRTL-SAC models are able to represent the data, with NRTL-SAC being better for pure solvent solubilities. Solubility dependence with temperature and solvent composition were also taken into account.
Whenever possible, the reference solvent approach was also applied, and the results were generally improved with any of the models. The average percent absolute deviations obtained for the representation of solubility data in pure solvents are very satisfactory, but for mixed solvents higher deviations are possible to find
Solid-liquid equilibria of some natural phenolic compounds: experimental and modelling
Phenolic compounds are typically found in plants, usually as esters
or glycosides [1]. Apart from being starting materials for many chemical
synthesis, there is also huge evidence that some phenolic compounds have
beneficial effects on human health.
In this work, the aqueous solubilities of some phenolic compounds
such as the hydroxybenzoic acids gallic, salicylic, protocatechuic and
syringic acids, and the phenilpropenoic acids caffeic, cinnamic, ferulic and
coumaric acids are addressed. Measurements were performed, as a function
of temperature, between 288 K and 323 K, at atmospheric pressure, using
constant-temperature jacketed equilibrium glass cells.
Approaches for modelling the measured data were evaluated,
including the modified UNIQUAC model [2] and the CPA equation of state
[3]
Solid-liquid equilibria of some pharmaceutical compounds
Solubility is an important property which affects the release, transport and absorption of drugs. Solubility data involving new drug molecules and their precursors are frequently unavailable hampering drug formulation. Although some thermodynamic models can be used, the existence of some experimental data is still fundamental for an appropriate model development and evaluation.
In this work, solubilities of some drugs, such as paracetamol, budesonide, allopurinol and flurosemide were measured as a
function of the temperature in several solvents, namely water, ethanol and acetone. Solubilities were determined by the analytical shake-flask method, using constant temperature jacketed glass cells for generating the saturated solutions, followed by composition analysis by HPLC. As the analytical shake-flask method is an expensive and time consuming procedure, an alternative method to measure solubility using DSC was also studied [1] with the advantage of being faster and consuming smaller amounts of sample. Melting data of the, pure drugs were also obtained by DSC.
The NRTL-SAC model [2j was used to represent the measured data. This model provides a simple and practical thermodynamic framework for phase equilibria of drug systems. A comparison between experimental and model results showed that NRTL-SAC is an appropriate tool to represent the solubility of these complex molecules
Solubilities of some pharmaceutical compounds in pure solvents
Solubility is an important property which affects the release, transport and absorption of drugs. It also affects drug’s efficacy, its future development and formulation effort [1]. Therefore, its measurements must be carried out in an initial step of the drug development. Solubility data involving new drug molecules and their precursors are frequently unavailable, which hampers the development and evaluation of predictive methodologies.
In this work solubilities of some drugs, such as paracetamol, budesonide, and furosemide, were measured, as a function of temperature, in several solvents, such as water, ethanol and acetone. The shake-flask method was used to obtain the saturated solutions and the compositions were determined by HPLC analysis. In spite of being the most reliable and standard technique to measure solubilities, it is very time consuming and is limited when samples are expensive and available in low amounts. An alternative methodology using differential scanning calorimetry [2] was used, with the advantage of being faster and consuming smaller quantities of sample
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