Synergistic effect of iontophoresis and chemical enhancers on transdermal permeation of tolterodine tartrate for the treatment of overactive bladder.

PURPOSE: The objective of the study was to evaluate the synergistic transdermal permeation effect of chemical enhancers and iontophoresis technique on tolterodine tartrate (TT) transdermal gel and to evaluate its pharmacokinetic properties. MATERIALS AND METHODS: Taguchi robust design was used for optimization of formulations. Skin permeation rates were evaluated using the Keshary-chein type diffusion cells in order to optimize the gel formulation. In-vivo studies of the optimized formulation were performed in a rabbit model and histopathology studies of optimized formulation were performed on rats. RESULTS: Transdermal gels were formulated successfully using Taguchi robust design method. The type of penetration enhancer, concentration of penetration enhancer, current density and pulse on/off ratio were chosen as independent variables. Type of penetration enhancer was found to be the significant factor for all the responses. Permeation parameters were evaluated when maximum cumulative amount permeated in 24 hours (Q24) was 145.71 ± 2.00µg/cm² by CIT4 formulation over control (91.89 ± 2.30µg/cm²). Permeation was enhanced by 1.75 fold by CIT4 formulation. Formulation CIT4 containing nerolidol (5%) and iontophoretic variables applied (0.5mA/cm² and pulse on/off ratio 3:1) was optimized. In vivo studies with optimized formulation CIT4 showed increase in AUC and T1/2 when compared to oral suspension in rabbits. The histological studies showed changes in dermis indicating the effect of penetration enhancers and as iontophoresis was continued only for two cycles in periodic fashion so it did not cause any skin damage observed in the slides. CONCLUSION: Results indicated that iontophoresis in combination with chemical enhancers is an effective method for transdermal administration of TT in the treatment of overactive bladder.

Synergistic effect of iontophoresis and chemical enhancers on transdermal permeation of tolterodine tartrate for the treatment of overactive bladder

Purpose The objective of the study was to evaluate the synergistic transdermal permeation effect of chemical enhancers and iontophoresis technique on tolterodine tartrate (TT) transdermal gel and to evaluate its pharmacokinetic properties. Materials and Methods Taguchi robust design was used for optimization of formulations. Skin permeation rates were evaluated using the Keshary-chein type diffusion cells in order to optimize the gel formulation. In-vivo studies of the optimized formulation were performed in a rabbit model and histopathology studies of optimized formulation were performed on rats. Results Transdermal gels were formulated successfully using Taguchi robust design method. The type of penetration enhancer, concentration of penetration enhancer, current density and pulse on/off ratio were chosen as independent variables. Type of penetration enhancer was found to be the significant factor for all the responses. Permeation parameters were evaluated when maximum cumulative amount permeated in 24 hours (Q24) was 145.71 ± 2.00µg/cm2 by CIT4 formulation over control (91.89 ± 2.30µg/cm2). Permeation was enhanced by 1.75 fold by CIT4 formulation. Formulation CIT4 containing nerolidol (5%) and iontophoretic variables applied (0.5mA/cm2 and pulse on/off ratio 3:1) was optimized. In vivo studies with optimized formulation CIT4 showed increase in AUC and T1/2 when compared to oral suspension in rabbits. The histological studies showed changes in dermis indicating the effect of penetration enhancers and as iontophoresis was continued only for two cycles in periodic fashion so it did not cause any skin damage observed in the slides. Conclusion Results indicated that iontophoresis in combination with chemical enhancers is an effective method for transdermal administration of TT in the treatment of overactive bladder. .

Pharmacokinetics of the orally administered decongestants pseudoephedrine and phenylpropanolamine in children.

BACKGROUND: There is little published, objective information about pseudoephedrine and phenylpropanolamine in the treatment of children. Our goal was to determine the pharmacokinetics of these medications in young subjects. METHODS: In two sequential double-blind, parallel-group, single-dose studies, 21 children received either pseudoephedrine, 30 or 60 mg, or placebo, and 20 children received either phenylpropanolamine, 20 or 37.5 mg, or placebo. Before dosing and at intervals up to 7 hours after dosing, serum pseudoephedrine or phenylpropanolamine concentrations were measured, and pulse and blood pressure were recorded. In two children receiving each drug, these tests were also performed at 12 and 24 hours, and urine was collected from 0 to 12 and from 12 to 24 hours. RESULTS: In children, the mean (+/-SEM) terminal elimination half-life values for pseudoephedrine, 3.1 +/- 0.5 hours, and for phenylpropanolamine, 2.6 +/- 0.6 hours, were significantly shorter than those found by other investigators in adults. Pharmacokinetics were not dose dependent in the dose ranges studied. CONCLUSION: Further studies of pseudoephedrine and phenylpropanolamine should be performed in children with the use of objective measurements. The widespread use of these medications in young subjects should be reevaluated.