Investigation of the semi-solid preparations with mometasone furoate on the emulsion bases

Abstract

Topicality. It is reasonably to introduce into the medical practice the medicinal product Mometasone cream 0.1 % based on the o/w emulsion for using in the acute phase of the inflammatory process. It is necessary to standardize and control the particle size of the dispersed phase in ointments and creams with mometasone furoate (MF), which have w/o emulsions as the vehicle.                  Aim. Investigation of the stabilization mechanism of w/o emulsions, which disperse phase contains 80 % hexylene glycol (HG), as well as the study of the of anti-inflammatory efficacy of semi-solid preparations with 0.1 % mometasone furoate (MF) and with viscous-plastic o/w and w/o emulsions as a bases, depending on the MF dispersion state and the particles size of the hydrophilic disperse phase of the w/o emulsions.                                                              Materials and methods. The objects of investigation were semi-solid preparations with 0.1 % MF and with o/w and w/o emulsions as bases, as well as the mixed solvents water – HG. In the experiment, laser diffraction and optical microscopy were used to determine the particle size; the rotating viscometer method was used for the study of rheological properties of emulsions; the method of spin probes was used for determination of the structure of the emulsifier associates, and the interfacial tension was determined by mass and volume of the drop. The anti-inflammatory effect of the drugs was studied using dextran induced paw edema as a model.                                                                                      Results and discussion. On the basis of the particles size distribution studies, the MF micronized substance was chosen and a medicinal product with viscous-plastic o/w emulsion as a basis, which contains 0.1 % MF as a suspension, was produced (Mometasone cream 0.1 %). It was revealed that HG at a content of more than 40 % w/w reduces the interfacial tension more than the emulsifiers, which makes their adsorption on the interfacial surface energetically unprofitable. By the EPR spectra parameters of the spin probes modeling w/o emulsifiers, it has been shown that in an emulsion, where the disperse phase is 80 % aqueous solution of HG, the w/o emulsifier forms a reverse micelles in a hydrophobic medium rather than adsorbed on the boundary of phase separation. It has been shown that the physical stabilization of such emulsions is related to the dispersion medium consistency, which depends on the temperature and shear stress during emulsion mixing. Taking into account the above mentioned critical factors, two samples of Mometasone ointment 0.1 % with w/o emulsion as a basis were prepared; these samples differ significantly in particles size of the dispersed phase, where MF is dissolved. It was found that in the conditions of dextran induced rat paw edema there is a pronounced tendency to a higher anti-inflammatory effect of Mometasone cream 0.1 % on the basis of the o/w emulsion, compared with Mometasone ointment 0.1 % on the basis w/o emulsion. Mometasone ointment 0.1 % on the basis of w/o emulsion with large particles of the disperse phase loses anti-inflammatory activity.                      Conclusions. According to the results of the study, it is rational to develop a cream with MF and the o/w emulsion as a basis; it is advisable to use this cream in the acute phase of the inflammatory process. During manufacture of the ointment with MF and with the w/o emulsion as a basis, it is necessary to strictly observe the production process parameters, as well as to standardize and control the particle size of the dispersed phase.