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The evaluation of the solubility of solid solutes in supercritical carbon dioxide is of paramount interest for the optimization of different supercritical based technologies. Most of the proposed approaches, at the end, give a method for the correlation only of the solubility and not a tool for the prediction. In this study, a modified NRTL equation, that includes the ratio of molar volumes of the two components, is used for the evaluation of the activity in the supercritical phase. Furthermore, the model is applied in the one parameter form according to the method already proposed by Tassios. The remaining cross interaction parameter is correlated to the difference of well know properties of pure compounds. The method is applied with satisfactory results to the description of the solubility of sterols in supercritical carbon dioxide in a wide range of temperature and pressure

The limited amount of fish oils available has led to extensive search for alternative sources of oils rich in long-chain n-3 polyunsaturated fatty acids (PUFA). Evidence from a large number of epidemiological studies, clinical studies and intervention trials have established the protective effect of omega 3 PUFA against several pathologies such as cardiopathies, diabetes and cancer. The fish oil remains the principal source of omega 3 even if a variety of alternative PUFA sources, such as bacteria, fungi, plants and microalgae are currently being explored for commercial production. The present study reports the extraction of perilla frutescens var frutescens seeds oil by means of supercritical carbon dioxide technique. Composition of the obtained extracts was analyzed by different techniques allowing a careful comparison with oil obtained from mechanical press extraction. Moreover, this plant of Asian origin, has been cultivated and bred in Italy.

This book chapter is aimed to provide, with a consistent section concerning the physical and chemical issues, the industrial uses of dichloromethane with particular attention to pharmaceutical, nutraceutical, and food purposes. Solubility data in different substances, were reported and estimated by means of Abraham’s model. Due to its toxicity and possible carcinogenic action, methods to avoid residuals in the treated materials such as pharmaceutical, nutraceutical or food compounds will be discussed. As an example, a literature experimental test on dichloromethane removal from a pharmaceutical drug, by supercritical carbon dioxide, is reported. Moreover, two other literature applications of dichloromethane in pharmaceutical technology field were considered.

A perturbed hard chain theory based equation of state is investigated in view of its application to supercritical fluid extraction process calculations. This investigation is an extension of a previous paper in which attention was given to pure component properties and in which a method was proposed for estimating the pure component parameters from the molecular structure. Binary systems of supercritical fluids and nonpolar molecules are considered in this paper. A method is proposed for estimating a priori the binary interaction parameter from molecular structure information. A universal set of parameters is found for hydrocarbon—supercritical fluid mixtures depending only upon the supercritical fluid and the hydrocarbon family. The results obtained are fairly good and comparable with other predictive equations of state available in the literature. The advantages of using this method is its integration with the pure component parameter estimation method proposed in a previous paper. Good results were also obtained in the prediction of the volumetric properties of the liquid and the vapor phase.

The purpose of this study is to investigate the influence of supercritical CO2 on the physicochemical properties of Piroxicam (PXC), a poorly soluble drug. The supercritical anti-solvent (SAS) technique was used to precipitate the drug at the pressure of 100 and 120 bar from three different solvents (acetone, ethylacetate and dichloromethane) to study how they would affect the final product. The samples were analyzed before and after the treatment to highlight possible changes in the habitus of the crystals.

In this work, a study has been carried out to prepare drug-polymer composites of Cefuroxime Axetil amorphous (CFA, antibiotic) loaded Polyvinylpyrrolidone (PVP-K30) by batch and continuous supercritical antisolvent (SAS) process. Solutions of (CFA + PVP-K30) in methanol or dichloromethane with overall concentrations of 50-150 mg/ml and drug/polymer ratios of 1/1-1/4 were sprayed with flow rates of 0.85-6 ml/min into the scCO2 at 100-150 bar and 35-50 °C. The effects of the process mode on the properties of the composite particles have been investigated. DSC, XRD and SEM analyses have been carried out to enlighten the particle formation mechanisms of two processes and to determine the relationship between the mechanism and product properties.

A method is proposed for the calculation of solubilities in compressed carbon dioxide. The method is illustrated with the hard-sphere equation of state, but the main feature is the use of low-pressure—low-temperature solubility data for determining the binary interaction parameters. Examples are reported for carbon dioxide because of its industrial use in supercritical fluid extraction.

5th Int. Symposium on High Pressure Process Technology and Chemical Engineering

Controlled – delivery products are finding considerable attention, because of their drug’s therapeutic effect prolongation, that keeps the drug concentration in the body between a lower limit (therapeutic limit) and an upper limit (toxicity limit). These devices are traditionally obtained by encapsulation of a drug in a polymer matrix using an organic solvent with the following steps: • Solubilization of the active principle in an organic solvent; • Partitioning of the active principle between the solvent and the polymer matrix; • Residual solvent removal. Problems arise for the elimination of residual solvent to acceptable limits. Antisolvent precipitation can be an alternative method for the encapsulation of a drug in a polymer matrix. In this study the feasibility of the technique, known as Supercritical Anti Solvent recrystallization (SAS), will be investigated in order to obtain the co-precipitation of a drug and a biodegradable polymer from an appropriate organic solvent. A biodegradable polymer, poly(L-lactide) (L-PLA) is considered, with a non steroidal anti-inflammatory drug (NSAID), nimesulide, as active principle.