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The kinetics of ultrasonic extraction of extractive substances (ES) from dry herbs of garden (Salvia officinalis L.) and glutinous (Salvia glutinosa L.) sage using petroleum ether, 70% ethanol or water at 40 degrees C, as well as the composition of dry extracts, were studied. The mechanism of ultrasonic extraction is confirmed to occur in two steps: first, dissolution of the ES near the particle surface (washing) and, second, diffusion from the solid particles to the bulk of the liquid extract (slow extraction). The process is described mathematically using three concepts of the unsteady diffusion through plant material, the film theory and the empirical equation of Ponomaryov. The yield of ES increases with increasing solvent polarity, and nearly the maximum concentration of ES in liquid extracts is achieved for about 20 min. The composition of extracts depends on both the extraction conditions applied and the plant material.

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The extraction of resinoids from St. John's wort (Hypericum perforatum L) was studied in a series of two papers. In the first part, the effects of the operating conditions on the yield of resinoids (total extract) were analyzed, while the mathematical models of extraction kinetics were compared in the second one. The extraction was carried out using an aqueous solution of ethanol (70 and 95 % v/v) at a hydromodulus (plant material to solvent ratio, w/v) of 1:5 or 1:10. The plant material was disintegrated and divided into three fractions (mean particle size: 0.23, 0.57 and 1.05 mm). The temperature was 25, 50 or about 80°C (boiling temperature). A higher yield of resinoids was obtained when the plant material of greater disintegration degree (0.23 mm) was treated with 70% v/v aqueous ethanol solution at higher hydromoduli (1:10) and temperatures (80°C). The effects of the operating factors on the yield of resinoids were estimated by using both the full factorial experimental plan 24 and artificial neuronic networks (ANN) of 3-4-1 topology. Of the two methods, the ANN one was found to be advantageous because of its capability of estimating the yield of resinoids in the whole range of the applied operating conditions

Cleaning validation procedures are carried out in order to assure that residues of cleaning agents are within acceptable limits after the cleaning process. Cleaning agents often consist of a mixture of various surfactants which are in a highly diluted state after the water rinsing procedure has been completed. This makes it difficult to find appropriate analytical methods that are sensitive enough to detect the cleaning agents. In addition, it is advantageous for the analytical methods to be simple to perform and to give results quickly. In this study, three different non-specific analytical methods are compared: visual detection of foam, pH and conductivity measurements. The analyses were performed on different dilutions of the cleaning agents Bactericidal Hydroclean and Tickopur R33. The results demonstrated that the most appropriate method for these detergents are conductivity measurements, by which it is possible to detect concentrations of cleaning agents down to 10 µg/ml. In this case, pH is an inadequate method (non-linear) and visual detection of foam is a semi--quantitative method. All these methods are easy to perform, gives a quick results, and requires no expensive instrumentation.The main objective of cleaning validation procedures is to provide documented evidence that the equipment is safe for the manufacture of the next product. For this purpose, cleaning agents are used for removal of the previously manufactured product and also for the removal microorganisms. Because cleaning agents often consist of a mixture of various surfactants, often very diluted, it may be difficult to find appropriate analytical methods that are sensitive enough for detection of the compounds.The first step in cleaning equipment is the selection of an appropriate cleaning product for the type of residue to be removed. Once this is done, an analytical strategy must be devised to determine the amount of cleaning agent residue left on surface that has been cleaned. This determination is important because if a cleaning agent effectively removes the drug--product residue but leaves behind its own residue, then one type of contamination has been exchanged for another, and the equipment has not been cleaned effectively. Detergent selection is a critical step in the Correspondening author: D. Milenović, "Zdravlje-Actavis" Company, 199 Vlajkova St.,

In the pharmaceutical industry, an important step consists in the removal of possible drug residues from the involved equipments and areas. The cleaning procedures must be validated and methods to determine trace amounts of drugs have, therefore, to be considered with special attention. An HPLC-UV method for the determination of digoxin residues on stainless steel surfaces was developed and validated in order to control a cleaning procedure. Cotton swabs, moistened with methanol were used to remove any residues of drugs from stainless steel surfaces, and give recoveries of 85.9, 85.2 and 78.7 % for three concentration levels. The precision of the results, reported as the relative standard deviation (RSD), were below 6.3 %. The method was validated over a concentration range of 0.05-12.5 ?g mL-1. Low quantities of drug residues were determined by HPLC-UV using a Symmetry C18 column (150?4.6) mm, 5 ?m) at 20?C with an acetonitrile-water (28:72, v/v) mobile phase at a flow rate of 1.1 mL min-1, an injection volume of 100 ?L and were detected at 220 nm. A simple, selective and sensitive HPLC-UV assay for the determination of digoxin residues on stainless steel was developed, validated and applied.

An HPLC method for digoxin quantification in dissolution samples obtained as per the official British Pharmacopeia (BP) method is presented in this paper. The chromatography was performed at 20 °C on a Symmetry C18; 3.5 ìm, 75 x 4.6 mm column with water - acetonitrile (72 : 28, v/v), as the mobile phase and UV detection at 220 nm. The method was found to be selective, linear, accurate and precise in the specified ranges. The LOD and LOQ were 0.015 μg mL-1 and 0.050 μg mL-1, respectively. Robustness testing was conducted to evaluate the impact of minor changes in the chromatographic parameters (i.e., acetonitrile fraction, flow rate of the mobile phase, column temperature and column length) on the characteristics of the digoxin peak. A. full factorial design (24) was used to investigate the influence of the four variables The presented HPLC method was applied in quality and stability testing of Digoxin tablets 0.25 mg