Drug in Adhesive Patch of Zolmitriptan: Formulation and In vitro/In vivo Correlation

The objective of the present study was to develop transdermal patch for zolmitriptan, determine its in vivo absorption using the rabbit skin. Solvent evaporation technique prepared zolmitriptan patch was settled in two-chamber diffusion cell combined with excised rabbit abdomen skin for permeation study. A sufficient cumulative penetration amount of zolmitriptan (258.5 +/- 26.9 mu g/cm(2) in 24 h) was achieved by the formulation of 4% zolmitriptan, 10% Azone, and adhesive of DURO-TAK (R) 87-4098. Pharmacokinetic parameters were determined via i.v. and transdermal administrations using animal model of rabbit. The results revealed that the absolute bioavailability was about 63%. Zolmitriptan could be detected with drug level of 88 +/- 51 ng/mL after transdermal administration of 15 min. The in vivo absorption curve obtained by deconvolution approach using WinNonlin (R) program was correlated well with the in vitro permeation curve, the correlation coefficient R is 0.84, and the result indicated that in vitro skin permeation experiments were useful to predict the in vivo performance. In addition, little skin irritation was found in the irritation study. As a conclusion, the optimized zolmitriptan transdermal patches could effectively deliver adequate drug into systemic circulation in short time without producing any irritation phenomenon and worth to be developed.