Effect of some ethoxylated sorbitan alkanoate on hydrocortisone release from methylcellulose gels

The process of hydrocortisone release from the nonionic polymer--methylcellulose hydrogels with the addition of 1% and 3% ethoxylated sorbitan alkanoate: polysorbate 20 or polysorbate 80, in the presence of 1,2-propylene glycol or PEG 200 has two stages. In the first stage the release rates are higher in comparison with the second stage. Concerning the hydrogel as a two-compartment system with micellas of polysorbates, the release rates of the first stage are in the range 4.27 x 10(-4)-6.23 x 10(-4) h-1 and in the second stage are in the range 8.29 x 10(-6)-1.16 x 10(-5) h-1 what can be affected by HLB of mentioned polysorbates.