2. Chiesi Farmaceutici SpA, Parma, Italy.
3. IRCCS Fondazione Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
4. Gastroenterology and Gastrointestinal Endoscopy Unit, IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy.
5. IRCCS Fondazione Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.
Background: The characterization of the rheological properties of topical formulations is important to predict their possible behaviour in clinical use.
Methods: Two commercially available suspension formulations of beclomethasone dipropionate (BDP) enemas (Formulation A and formulation B) were analysed to define their rheological characteristics under different conditions.
Results: The different composition of the two tested formulations led to important differences in their rheological properties. The results showed that formulation A has viscoelastic gel-like properties, whereas formulation B has viscous-fluid characteristics. A gel-like behaviour and pronounced elastic properties may determine longer time of drug permanence in the site of action. Formulation A retained its rheological properties to a greater extent than did Formulation B across a range of stresses that simulate the agitation of the container before using. A gel-like behaviour may be associated to a high ability to recompose the deformation once the stress is ceased. A more pronounced structural integrity may be indicative of a higher stability of formulation A compared to formulation B.
Conclusions: These different rheological properties between the two examined BDP enemas formulations may lead to important differences in the performance in clinical practice, which should be demonstrated in appropriate randomized clinical trials.
Keywords: Beclometasone Diproprionate, suspension, colitis, rheological viscosity