Influence of emulsoid vehicle on the release and activity of allantoin

Samples which contain 2% (w/w) of allantoin in various emulsified vehicles were prepared and characterized. The influence of vehicle on releasing and diffusion of allantoin through semipermeable membrane into an aqueous medium was examined and the quantity of released allantoin was estimated spectrophotometrically. The best results were achieved with ambiphilic vehicle emulsified with complex Tagat S-Tegin M which in the aqueous phase contained propylene glycol (sample A2). On the contrary, with both lanacolic vehicles, the poorest results were achieved in vitro. On the basis of the results for clinical evaluation, the best preparation was chosen (A2) and the preparation with lanacolic vehicle which contains propylene glycol (B2). Before the application of samples, each patient was tested for irritation and sensitization. All test were negative. During further clinical examinations on patients suffering from psoriasis an open double trial for the duration of 14 d was performed. For the evaluation of the efficacy of the examined preparations, objective parameters of the clinical picture were observed (the state of hyperkeratosis, of erythema and infiltration) as well as subjective parameters which were evaluated by the patients themselves. When the in vitro results are compared with clinical estimation, it is evident that they correspond only when characteristics of the preparation are estimated by patients (smearing, absorption and feeling on the skin), because the best preparation was in these cases A2. Both preparations are equally good when regression of subjective symptoms is evaluated (itching and burning). In the objective evaluation of the regression of visible symptoms, such as hyperkeratosis and erythema, results of the clinical experiment do not correspond with results in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)