Formulation and optimization of desogestrel transdermal contraceptive patch using crystallization studies.

Levonorgestrel (LNG) is the most commonly used progestin in contraception. In this study, we report the use of an alternative progestin, desogestrel, for transdermal contraception. The drug was found to be significantly more permeable as compared to LNG (p<0.05). Crystallization studies were used to select the best adhesive among acrylate (Duro-Tak 87-4098 and Duro-Tak 87-202A) and polyisobutylene (PIB, Duro-Tak 87-608A) pressure sensitive adhesives by determining the drug's saturation solubility in them. The use of copovidone and mineral oil as formulation excipients was investigated to increase drug loading in the PIB adhesive. Physical characterization of the patches was performed using in vitro drug release, content analysis, patch weight and thickness variations and rolling ball tack and peel adhesion studies. Optimized patches were evaluated for in vitro transdermal delivery across hairless rat skin. The saturation solubility of desogestrel was found to be approximately 49.3% (w/w) and 55.6% (w/w) in Duro-Tak 87-4098 and Duro-Tak 87-202A acrylate adhesives, respectively. The saturation solubility of desogestrel was significantly lower (3-4%, w/w) in the PIB adhesive. Mineral oil (10%, w/w) and copovidone (30%, w/w) were found to be optimum for increasing drug loading and patch cosmetics. Results from the physical characterization studies suggest that a uniform and reproducible 7 day drug-in-adhesive patch could be developed.

Use of a sulfated chitosan derivative to reduce bladder inflammation in the rat.

OBJECTIVES: Interstitial cystitis is a chronic, debilitating disease of the bladder. Treatments using intravesicular inoculation of long-chain polysaccharide formulations, such as hyaluronic acid or anti-inflammatory agents, have been used to some effect. The objective of this study was to test a long-chain polysaccharide derivative of chitosan as a vehicle for delivery of the anti-inflammatory agent 5-aminosalicylic acid (5-ASA) for treatment of inflammation in the bladder. METHODS: Bladder inflammation was induced in rats by intravesicular inoculation of protamine sulfate and lipopolysaccharide. Groups of rats were randomly assigned to the treated or control groups, which received either the treatment agents or saline 24 hours after induction. The animals were killed 5 days after inoculation, and the bladders harvested for histologic examination of inflammation by a blinded observer. Four parameters of inflammation were measured using a 6-point scale. In another experiment, urinary frequency was measured 4 days after inoculation. RESULTS: The most potent treatment agent was 3% N-sulphonato-N,O-carboxymethylchitosan plus 5-ASA, with a mean reduction in inflammation, as measured by histologic examination, of up to 75%. This level of reduction was significantly greater than that seen by treatment with the commercially available product Cystistat. In a separate experiment, 3% N-sulphonato-N,O-carboxymethylchitosan plus 5-ASA ameliorated the increase in urinary frequency seen in induced, untreated animals. CONCLUSIONS: The combination of 3% N-sulphonato-N,O-carboxymethylchitosan and 5-ASA reduced bladder inflammation as measured by histologic examination and by the lower urinary frequency.