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The effects of β-cyclodextrin (β-CD) on the solubility properties of lidocaine base were studied. Products were prepared by physical mixing, kneading, spray-drying and precipitation methods in drug : β-CD ratios of 3:1, 2:1, 1:1, 1:2 and 1:3. Some auxiliary materials (hydroxy acids, etc.) were also used. The solubility and the rate of dissolution both in distilled water and in artificial gastric juice, the in vitro diffusion, the thermoanalytical properties (TG, DTG, DSC and DTA) and the surface tension were determined, and the measured results were compared with the corresponding data for lidocaine hydrochloride.

Inclusion complexation between dimethyl-β-cyclodextrin and a very poorly water-soluble serum lipid-regulating agent, gemfibrozil, was studied. Products were prepared by several methods (physical mixing, kneading, spray-drying and ultrasonic treatment) in four different molecular ratios (2:1, 1:1, 1:2 and 1:3). The possibility of complex formation between the drug and the host molecule was studied by thermal analysis. Supplementary techniques, such as Fourier transformation-infrared spectroscopy and X-ray diffractometry, were also applied to interpret the results of thermal study of the products.

Gemfibrozil (GEM) is a xylyloxi-valeric acid derivative with an antilipaemic effect. This molecule has very poor water solubility, and the ability of different cyclodextrins (CDs) to form inclusion complexes was therefore tested. Primarily heptakis-2,6-di-O-methyl-β-cyclodextrin (DIMEB) was found to increase the solubility. The preparation of the complex in solid form for characterization was successful by means of physical mixing, kneading, spray-drying and ultrasonic treatment. The dissolution and in vitro membrane diffusion of the products were investigated. The n-octanol/water partition coefficients were determined for pure GEM and the DIMEB inclusion product, and the interactions leading to complex formation between the components of the products were examined by thermoanalytical methods and FTIR spectrophotometric analysis.

Inclusion complexation between cyclodextrin derivatives (hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin) and a very poorly water-soluble antifungal agent, ketoconazole, was studied. Solid products were prepared by physical mixing, kneading and spray-drying methods in four molecular ratios: 2:1, 1:1, 1:2 and 1:3. The possibility of complex formation between the drug and the cyclodextrins was studied by thermal analysis. Supplementary techniques, such as X-ray diffractometry and Fourier transformation-infrared spectroscopy, were also applied to interpret the results of the thermal study of the products.

The aim of this study was to compare the adsorption of various organic drugs and a well-studied surfactant. The organic drugs used were promethazine chloride [10-(2-dimethylammonium) propylfenothiazine chloride] and buformin hydrochloride (1-butylbiguanidine chloride). The surfactant was benzalkonium chloride (N-tridecyl-N-benzyl-N,N-dimethylammonium chloride). Different amounts of drug solutions were added to montmorillonite suspensions, either separately (simple system) or in combination (competitive system) under the same conditions, and the organocomplexes formed were investigated. The organic molecule with the short alkyl chain adsorbed to yield monolayer coverage, whereas the aromatic molecule and the surfactant formed a pseudotrimolecular arrangement. In the competitive system, the larger organic molecules (having the same charge) displaced the smaller one from the interlayer space. The intercalation of molecules in the interlayer space was investigated by X-ray diffraction measurements.

Nifluminic acid (N) is a frequently used anti-inflammatory drug,but its poor aqueous solubility is a disadvantageous property. Inclusion complexation with cyclodextrinderivatives (CDs) affords a possibility to increase its solubility properties. For thispurpose, different CDs were used, primarily hydroxypropyl-β-CD (HP-β-CD), to prepareproducts by powder mixing or kneading in four molecular ratios. The dissolution and in vitromembrane diffusion of the products were investigated. The wetting angles of pure N andHP-β-CD and of the products, and the n-octanol/water partition coefficients were determined.The interaction, leading to complex formation between the components of the products was examined by thermoanalytical methods.

Tenoxicam is a widely used non-steroidal anti-inflammatory drug (NSAID). Itscomplexation with cyclodextrin was studied in order to improve its aqueoussolubility and to decrease its side-effects. Two- and three-component systems inseveral mole-ratios were prepared by means of two different methods. The drugliberation profile, the in vitro membrane diffusion and the n-octanol/water partitioncoefficient were investigated. The presence of complexes was detected via thermoanalyticaland X-ray diffractometric studies. On the basis of these data, several compositionswere selected for incorporation into topical dosage forms.

In pharmaceutical practice it is important and useful to know the crystallinity of materials and to monitor it during formulation development, production processes and storage. The purpose of this study was to assess the quantitative capability of DSC for determining crystallinity in crystalline/amorphous powder mixtures and to compare the accuracy of the DSC method with that of conventional powder X-ray diffraction. Alpha-lactose monohydrate was chosen as the model material. On the basis of this study it can be concluded, that DSC method can be applied safely for semiquantitative evaluation of the crystallinity of lactose samples consisting of an amorphous content higher than 20%.

Cyclodextrin complexation was applied to achieve better aqueous solubility of the drug and to formulate suppositories. Binary products were prepared in several mole ratios by two different methods. The dissolution profiles and in vitro membrane diffusion behaviour of the compositions were investigated. Thermoanalytical studies were performed in order to confirm inclusion complex formation. Compositions were selected for further detailed investigations and for incorporation into suppository dosage form.

The adsorption of promethazine chloride [10-(2-dimethylammonium propyl) fenothiazine chloride] and buformin hydrochloride (1-butylbiguanidine chloride) on montmorillonite was studied in previous work. The present article focuses on the desorption of these molecules from their organocomplexes in a medium of artificial intestinal juice (pH 7.0 ± 0.1) at the temperature of the human body (37 ± 0.5 °C). The desorption was investigated by kinetic studies, basal spacing measurements and Fourier transform IR studies. Important quantitative differences were observed: buformin, which adsorbed in a monolayer coverage, exhibited a very high desorption rate, whereas promethazine formed a pseudotrilayer arrangement and showed a lower dissolution rate.

One of the most important task of the pharmaceutical technology is to reach a possible high gastrointestinal absorbtion of the active ingredient. Therefore, it is necessary to have a good solubility in the gastric/intestinal medium. In this way the applied drug quantity and unwanted side effects can be reduced with solubility increasing. The water-insoluble drug's solubility and bioavailability can be increased by the alteration of their physicochemical properties. Nifluminic acid is a frequently used anti-inflammatory drug with low aqueous solubility. Inclusion complexation with cyclodextrins is an efficacious method to improve the solubility, stability and bioavailability. Ternary systems were prepared and investigated to use nifluminic acid, hydoxypropyl-beta-cyclodextrin and polyvidone. The aims of the study were to investigate the solubility rate, the in vitro diffusion ability, to determine the n-octanol/water partition coefficient, and to study the thermoanalitycal properties of products. The results suggested that complexation with cyclodextrin and the use of polyvidone is better method than to prepare binary systems. Inclusion complexation was presumed in the event of the ternary composition to improve the bioavailability of nifluminic acid.