The synthesis of ring-contracted derivatives of erythromycin A via intramolecular transesterification under microwave irradiation of 8,9-anhydroerythromycin A 6,9-hemiketal and its derivatives is described. It was found that microwave irradiation could significantly improve the yields and shorten the reaction times under either solvent-containing (method A) or solvent-free (method B) conditions.

The objective of this investigation was to develop the hollow microspheres as a new dosage form of floating drug delivery system with prolonged stomach retention time. Hollow microspheres containing ranitidine hydrochloride were prepared by solvent evaporation method using Eudragit RLPO dissolved in a mixture of dichloromethane and ethanol. The maximum yield and drug loading amount of hollow mi...

Mechanical extraction: this traditional method of cottonseed oil extraction uses a circular mortar (called ghani in India, Achaya, 1993) or more advanced technology, such as a hydraulic press or a screw press (expeller). The cotton seeds may be dehulled, cracked, dried or heated before being fed to the press. The resulting cake is dried, ground and then processed into large pellets (Ash, 1992)....

We present a physically rigorous method to calculate solvent-dependent accessible surface areas (ASAs) of amino acid residues in unfolded proteins. ASA values will be larger in a good solvent, where solute-solvent interactions dominate and promote chain extension. Conversely, they will be smaller in a poor solvent, where solute-solute interactions dominate and promote chain collapse. In the met...

Mesoporous photocatalysts of CeO2/SBA-15 are prepared by two methods of direct synthesis as solvent-usage and solvent-free methods. In solvent-usage method, CeO2/SBA-15 is synthesized in acidic media. While, in solvent-free method, CeO2/SBA-15, has been prepared through the novel path of directly grind cerium salt into the as-prepared samples of SBA-15 occluded ...

In many M.D. simulations the simulated system consists of a single macromolecule in a solvent. Usually, one is not interested in the behaviour of the solvent, so, the CPU time may be minimized by minimizing the amount of solvent. For a given molecule and cut-off radius this may be done by constructing a computational box with near minimal volume. In this article a method is presented to constru...

In the proposed method, carbon tetrachloride and ethanol were used as extraction and dispersive solvents. Several factors that may be affected on the extraction process, such as extraction solvent, disperser solvent, the volume of extraction and disperser solvent, pH of the aqueous solution and extraction time were optimized. Under the optimal conditions, linearity was maintained between 1.0 ng...

A rapid and sensitive method has been developed for the determination of benzaldehyde, a toxic oxidation product of the widely used preservative and co-solvent benzyl alcohol in injectable formulations of non-steroidal anti-inflammatory drugs, diclofenac, vitamin B-complex and Voltaren injection solutions by using dispersive liquid-liquid microextraction followed by gas chromatography. This met...