Design and development of SMEDDS for colon-specific drug delivery

Lipoidal systems have particularly shown potential for specific accumulation in areas with inflamed tissue increasing the selectivity of local drug delivery.

Formulation and evaluation of self-microemulsifying drug delivery system (SMEDDS) for colon-specific drug delivery for effective treatment of colonic diseases.

Ternary phase diagram was used to optimize level of oil, surfactant and co-surfactant to optimize SMEDDS and were evaluated for percent transmittance, emulsification time, in vitro release, myeloperoxidase (MPO) activity and intestinal accumulation. The spray dried SMEDDS were filled in capsules which were enteric coated with Eudragit S-100 at 10% weight gain to ensure SMEDDS delivery at colon. The spray dried SMEDDS were also evaluated for IR, DSC, XRD, SEM and stability study.

In ternary phase diagram, Capmul MCM C8 and Capmul PG12 NF with surfactant (Tween 20) and co-surfactant (PG) in ratio 2:1 and 3:1, respectively, showed maximum emulsification area. These liquid SMEDDS show maximum transmittance, globule size of 90-30 nm. The spray-dried SMEDDS with diluents show good flow property. The units of MPO activity show lower level as compared to pure drug and control group, histopathology results supports better healing with SMEDDS. This was attributed to accumulation of SMEDDS in inflammatory area as compared to drug which was further proved by accumulation study. Enteric-coated capsule containing SMEDDS are able to deliver drug, specifically at the colonic region.

Higher accumulation of lipoidal drug in inflammatory area and specific release of liposomes by enteric-coated capsules provide better option for the treatment of colonic disease.