title: Photostability and ex-vivo permeation studies on diclofenac in topical niosomal formulations.
abstract: Photostability studies were performed on topical formulations containing diclofenac (DC). Niosomal gels were designed as photostabilization systems and ascorbic acid was also added to the new topical formulations because of its antioxidant property. Photodegradation tests were applied on commercial formulations containing DC and novel prepared gels, according to the ICH rules. The experiments were monitored by spectrophotometry and the data processed by multivariate curve resolution analysis to estimate the spectra and concentration profiles of evolved components. Characterization of niosomes was evaluated by size and distribution measurement, morphological analysis and encapsulation efficiency. Permeation experiments were performed across rabbit ear skin up to 24 h. Photodegradation rate of DC was found very fast in commercial formulation, with a residual content of 90% after only 4.38 min under a radiant exposure of 450 W/m(2). Photostability resulted increased significantly when the drug was entrapped in niosomal systems. The best results were obtained by reaching a 10% degradation after 50.00 min of light exposure after incorporation of DC in niosomes in presence of 5% ascorbic acid. Moreover, niosomal gel also influenced the permeation capability of DC by enhancing the transdermal delivery of the drug. The cumulative dose permeated of DC from niosomal gel was about three times that obtained with the commercial gel.
authors: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende (CS), Italy. Electronic address: giuseppina.ioele@unical.it.
authors: Giuseppina
authors: G
authors: Ioele
authors: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende (CS), Italy.
authors: Lorena
authors: L
authors: Tavano
authors: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende (CS), Italy.
authors: Michele
authors: M
authors: De Luca
authors: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende (CS), Italy.
authors: Gaetano
authors: G
authors: Ragno
authors: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende (CS), Italy.
authors: Nevio
authors: N
authors: Picci
authors: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende (CS), Italy.
authors: Rita
authors: R
authors: Muzzalupo
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000737:chemistry; D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004008:Diclofenac / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D004355:Drug Stability; D005782:Gels / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D008081:Liposomes; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D010782:Photolysis; D011817:Rabbits; D012869:Skin Absorption
chemical_list: D005782:Gels; D008081:Liposomes; D004008:Diclofenac; D001205:Ascorbic Acid
keywords: Ascorbic Acid; Ascorbic Acid (PubChem CID: 54670067); Diclofenac sodium salt (PubChem CID: 5018304); MCR analysis; Niosomal gel; Percutaneous permeation study; Photodegradation studies; Photostabilization