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selected as pressure sensitive adhesive as it showed the best results. In patch
formulation, crystallization inhibitor was used along with pressure sensitive adhesive, to
achieve the highest drug loading. Various crystallization inhibitors were evaluated out of
which PVP K30 was selected. Various penetration enhancers were evaluated out of which
the best penetration enhancer selected was Transcutol HP. Using Design Expert software,
the Transdermal patch was optimized using the face central composite design. Drug
concentration, crystallization inhibitor concentration, and penetration enhancer
concentration were the selected factors for optimization. Responses selected were
percentage cumulative drug release after 12 hours and indicative 180° peel adhesion
strength. The optimised formulation showed the assay of 98.67 ± 0.86. 180° peel
adhesion strength of 202.37 ± 5.28 gram. The patch thickness was found to be 431 ± 15
μm. Percentage cumulative drug diffused after 12 hours was found to be 64.89 % ± 1.04
%. The optimized formulation was evaluated for a stability study that showed that the
formulation was stable.

Key words: Atomoxetine Hydrochloride, Attention Deficit Hyperactivity Disorder,
Transdermal, Microemulsion based gel, Monophasic System, Simplex Lattice Mixture
Design, Drug in Adhesive Patch, Face Central Composite Design

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