Topical Pilocarpine Formulation for Diagnosis of Cystic Fibrosis.

Cystic fibrosis is diagnosed in infants by estimating the levels of chloride ions present in the sweat induced by iontophoresis of pilocarpine solution. Elevated levels of chloride (≥60 mMol/L) in sweat are indicative of cystic fibrosis. However, the iontophoretic method of delivering pilocarpine is cumbersome and usually is associated with several side effects such as skin burn, skin rashes, erythema, and so forth. The objective of this study was therefore to develop a topical formulation that delivers adequate amount of pilocarpine. The drug delivery of formulation was compared with iontophoresis of aqueous solution of pilocarpine nitrate in vitro using porcine skin model. The pilocarpine levels in the skin exposed to topical pilocarpine solution under mild hyperthermia was 152.04 ± 52.23 μg/cm after 10 min of application, whereas it was 97.05 ± 27.93 μg/cm in the skin after 10 min of iontophoresis. The topical formulation was subjected to clinical evaluation to assess the efficacy of the product to induce sweat production. The average amount of the sweat secreted on application of topical formulation was found to be 77.28 ± 18.97 mg. Based on these results, it was found that the topical formulation was successful in delivering pilocarpine and to stimulate sweat secretion.