and full-text of published articles. The journal is devoted to the promotion of health sciences and related disciplines (including medicine, pharmacy, nursing, biotechnology, cell and molecular biology, and related engineering fields). It seeks particularly (but not exclusively) to encourage multidisciplinary research and collaboration among scientists, the industry and the healthcare professionals. It will also provide an international forum for the communication and evaluation of data, methods and findings in health sciences and related disciplines. The journal welcomes original research papers, reviews and case reports on current topics of special interest and relevance. All manuscripts will be subject to rapid peer review. Those of high quality (not previously published and not under consideration for publication) will be published without delay. The maximum length of manuscripts should normally be 10,000 words (20 single-spaced typewritten pages) for review, 6,000 words for research articles, 3,000 for technical notes, case reports, commentaries and short communications.
Ordered mixtures consist of adhering fine particles of a hydrophobic drug to the surface of larger particles of a water soluble carrier substance (1). Carrier particles dissolve in the presence of water, whereby adherent particles of the pharmaceutical substance disperse throughout the liquid. This eliminates the inherent tendency of hydrophobic drug particles to collect into not-readily dissolvable and dispersible aggregate. Literature reveals that various water soluble excipients such as lactose, mannitol, sorbitol and sodium chloride have been extensively used in preparation of ordered mixtures (1-3).Gliclazide is 1-(3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-2-yl)-3-(4-methylphenyl)sulfonylurea with molecular mass of 323.41 (PubChem Database; http://pubchem. ncbi.nlm.nih.gov). Gliclazide is used for the treatment of type II non-insulin dependent The poorly water soluble antidiabetic drug gliclazide was selected to study the effect of excipients on dissolution rate enhancement. Ordered mixtures of micronized gliclazide with lactose, mannitol, sorbitol, maltitol and sodium chloride were prepared by manual shaking of glass vials containing the drug and excipient(s). Different water soluble excipients, addition of surfactant and superdisintegrant, drug concentration and carrier particle size influenced the dissolution rate of the drug. Dissolution rate studies of the prepared ordered mixtures revealed an increase in drug dissolution with all water soluble excipients. The order of dissolution rate improvement for gliclazide was mannitol > lactose > maltitol > sorbitol > sodium chloride. Composite granules of the particle size range 355-710 mm were superior in increasing the drug dissolution rate from ordered mixtures. Reducing the carrier particle size decreased the dissolution rate of the drug as well as the increase in drug concentration. Kinetic modeling of drug release data fitted best the Hixson--Crowell model, which indicates that all the ordered mixture formulations followed the cube root law fairly well.
The objectives of this investigation were to prepare microspheres of the anti-diabetic drug, metformin hydrochloride, using ethyl cellulose as the polymer and evaluate the encapsulation efficiency and release characteristics in vitro and in vivo; utilizing different microencapsulation techniques. Different proportions of polymer were used to obtain varying drug-polymer ratios. Physical properties, loading efficiency and dissolution rate were dependent on the method chosen for preparation and also on the drug-to-polymer ratio. The addition of surfactant during emulsification and petroleum ether in non-solvent addition process affected release of drug and also size distribution of microspheres. To investigate the type of mechanism that occurs, dissolution data were plotted according to different kinetic models. In vitro release studies show first order and Higuchi model release characteristics being exhibited. All the results were treated statistically to validate the findings. Significant differences in percentage yield, entrapment efficiency and sustaining capacity were seen with microspheres prepared by two different methods. In vivo studies in normal and hyperglycemic mice show faster glucose reduction with microspheres prepared by the evaporation method, whereas the release sustaining effect was more pronounced with microspheres prepared by the non-solvent addition method.
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