L.V. Ovsyannikova - Post-graduate Student, First Moscow State Medical University of I.M. Sechenov
I.I. Krsanuk (junior) - Dr.Sc. (Pharm.), Professor, First Moscow State Medical University of I.M. Sechenov
A.V. Belyatskaya - Associate Professor, First Moscow State Medical University of I.M. Sechenov
O.I. Nikulina - Post-graduate Student, First Moscow State Medical University of I.M. Sechenov
V.V. Grikh - Post-graduate Student, First Moscow State Medical University of I.M. Sechenov. E-mail: liky145@gmail.com

It is known that about 60 % of the substances are slightly soluble in water. Low solubility is one of the important problems in pharmaceutical technology. The promising way to improve the technology and increase the bioavailability (BA) is the method of solid dispersions (SD) [2, 3]. The previously established increase in the solubility of diclofenac from SD related to the size of the drug substance (LP).The purpose of this research is studying microcrystalloscopy and optical properties of diclofenac (acid form) as a substance and SD with polyvinylpyrrolidone-10000 (PVP) and polyethylene glycol-1500 (PEG). SD were prepared by removing the solvent. Non micronized diclofenac microscopy was performed by applying to a glass slide and microscopy in liquid paraffin. Recrystallized diclofenac and SD on the glass slide were obtained by evaporating the solution of the LP or SD in ethanol. The studies were performed using a digital microscope STL-BL900 [1]. The phenomenon of light scattering was observed with side lighting rays of the test solution in darkness. The solutions were filtered through nozzles Minisart with a pore size of 1.2 µm. The reasons for increasing the solubility of the LP from SD may be associated with a decrease in the crystallinity of the LP in SD and obtaining a colloidal solution. According to microcrystalloscopy objects under study are as follows: diclofenac - shapeless small fragments of opaque crystalline particles, which were previously machined. Recrystallized diclofenac - stellate clusters of needles. Polymers - clear, colorless mass: PEG - scaly structure of polyhedra towering cone over a plane, PVP - transparent surface covered with grooves. SD with PEG - scaly structure of large irregular polyhedra with a rough surface, it is similar to the picture of PEG, crystals of the LP are not observed; SD with PVP don-t contain crystals of the LP, represents solution of diclofenac in polymer, the picture is identical to PVP after the removal of ethanol. The study of optical properties was conducted for the LP solutions and its SD with PEG. Unlike the solutions of the polymers and LP by passing the light through the solution of SD there are observed opalescence and Tyndall cone due to the colloidal station of the LP. The findings indicate a loss of crystallinity of diclofenac in SD, preparing solid solution of the LP in the polymer. Diclofenac from SD dissolves in colloidal form that enhances the solubility of the LP from SD. The results will be used to improve the BA of new diclofenac dosage forms.