Topical Cream-Based Dosage Forms of the Macrocyclic Drug Delivery Vehicle Cucurbit[6]uril

The macrocycle family of molecules called cucurbitn]urils are potential drug delivery vehicles as they are able to form host-guest complexes with many different classes of drugs. This study aimed to examine the utility of Cucurbit6]uril (CB6]) in topical cream-based formulations for either localised treatment or for transdermal delivery. Cucurbit6]uril was formulated into both buffered cream aqueous- and oily cream-based dosage forms. The solid state interaction of CB6] with other excipients was studied by differential scanning calorimetry and the macrocycle''s transdermal permeability was determined using rat skin. Significant solid state interactions were observed between CB6] and the other dosage form excipients. At concentrations up to 32% w/w the buffered aqueous cream maintained its normal consistency and could be effectively applied to skin, but the oily cream was too stiff and is not suitable as a dosage form. Cucurbit6]uril does not permeate through skin; as such, the results imply that cucurbituril-based topical creams may potentially only have applications for localised skin treatment and not for transdermal drug delivery.