tolterodine-tartrate and isopropyl-myristate

To design and optimize a drug-in-adhesive (DIA) type transdermal patch for tolterodine (TOL) based on acrylic and silicone matrixes.. Initial in vitro studies were conducted to optimize the formulations. Two types of adhesive matrixes, drug loading, and enhancers were evaluated on the TOL transport across rabbit skin. For in vivo studies, patches were administered to rabbit abdominal skin. Pharmacokinetic assessments were performed based on plasma level of TOL up to 28 h for acrylic patch and 52 h for silicone patch after topical application.. The final formulation of acrylic adhesive type patch consisted of 10% TOL (w/w) and 5.8 × 10(-4) mol isopropyl myristate (IPM) and 2.9 × 10(-4) mol Span 80 in per unit gram (mol/g) of adhesive, while 2.5% TOL (w/w) and 2.9 × 10(-4) mol/g IPM for silicone adhesive type patch. Comparison of the pharmacokinetic parameters between two types of patches showed that the steady-state concentration of silicone type patch was 2-fold higher than that of acrylic type patch being 0.97 mg/L versus 0.49 mg/L, and the absolute bioavailability was 27.5% for silicone type patch and 6.3% for acrylic type patch, respectively. In addition, the prediction of in vivo drug level from the in vitro permeation data of silicone adhesive formulation was in good agreement with actual observed concentration data in rabbits.. These results indicate that the silicone type of TOL patch is an appropriate delivery system for the treatment of overactive bladder (OAB).

Topics: Adhesives; Administration, Cutaneous; Animals; Benzhydryl Compounds; Biological Availability; Chemistry, Pharmaceutical; Cresols; Drug Delivery Systems; Male; Myristates; Phenylpropanolamine; Rabbits; Silicones; Skin; Skin Absorption; Tolterodine Tartrate; Transdermal Patch; Urinary Bladder, Overactive

The aim of the present investigation was to evaluate the percutaneous absorption of tolterodine (TOL) using O-acylmenthol derivatives as enhancers as well as to correlate their enhancing activity under in vitro and in vivo conditions. The in vitro permeation studies of TOL were conducted in isopropyl myristate (IPM) solution or from patches in side-by-side diffusion cells. TOL pharmacokinetic parameters were determined after intravenous administration and topical application of patches without enhancer or with l-menthol and (E)-2-isopropyl-5-methylcyclohexyl octadec-9-enoate (M-OA) as enhancers in rats. The in vitro permeation studies indicated that M-OA was the most promising enhancer for transdermal delivery, as 2-isopropyl-5-methylcyclohexyl 2-hydroxypanoate (M-LA) was merely effective in IPM solution. There was no significant difference between the control and l-menthol group in terms of the flux before patches were removed, while the skin reservoir effects of the enhancer-containing groups were significantly greater than that of the control group. The mean steady-state plasma concentrations after applying patches without enhancer or with l-menthol and M-OA as enhancers were 0.89, 0.84 and 1.47 microg/mL, respectively. The in vivo results observed from the three types of patches in rats were in good agreement with the plasma concentrations predicted from the in vitro data.

Topics: Administration, Cutaneous; Animals; Benzhydryl Compounds; Chemistry, Pharmaceutical; Cresols; Diffusion Chambers, Culture; Excipients; Male; Menthol; Muscarinic Antagonists; Myristates; Permeability; Phenylpropanolamine; Rats; Rats, Wistar; Skin Absorption; Tolterodine Tartrate