Page 24 - 2021

Ph.D.
(Pharmacy)
DEVELOPMENT & CHARACTERIZATION OF TRANSDERMAL
FORMULATIONS FOR TREATMENT OF ADHD

Ph.D. Scholar : Barot Tularam Baldevsinh
Research Supervisor : Dr. B. G. Prajapati

Regi. No.: 15146021001
Abstract :
For the development of formulations for the treatment of ADHD, three approaches were
evaluated. The first approach developed was a micro emulsion-based gel formulation.
Microemulsions are widely used as a drug delivery approach for transdermal
formulations. For developing microemulsion-based formulation, the solubility of the drug
was determined in different oils, surfactants & co-surfactants and it was observed that
Atomoxetine Hydrochloride showed its best solubility in CapmulMCMC8 EP, Cremophore
RH 40, and PEG 400 respectively. The best Smix ratio was found to be 3:1. The
microemulsion was optimized using a mixture optimal design. The optimized formulation
was evaluated for various evaluation parameters. The optimized microemulsion was
incorporated in the gel base to obtain the final dosage form. The drug release study of the
final gel was performed ex-vivo using Franz diffusion cell using rat skin as a transdermal
barrier. In the second approach, a monophasic transdermal system was developed. Here,
two main factors affecting diffusion are targeted for enhancement of diffusion which is –
higher drug concentration gradient and lower path resistance. Higher drug concentration
has been achieved by choosing a solvent that is skin compatible and can dissolve the
highest amount of drug in it. While for lowering path resistance, penetration enhancers
are used. Penetration enhancers change the property of the skin horny layer so that the
resistance becomes less. Capmul MCM C8 was selected as the vehicle because the drug
Atomoxetine Hydrochloride has the highest solubility in it. Formulation viscosity was
found to be optimum with the use of PVP K90 at 14.44% w/w concentration. Various
penetration enhancers were evaluated, out of which ethanol and Trancutol HP showed
the highest results. The monophasic transdermal formulation was optimised using
Simplex Lattice mixture design. The selected factors were concentrations of oil (Capmul
MCM C8), Transcutol HP, and ethanol. Responses selected were percentage cumulative
drug diffused after 4 hours and percentage cumulative drug diffused after 12 hours.
Optimised batch was evaluated for viscosity, spreadability, assay, and cumulative
percentage drug diffusion study. Optimized formulation showed 91.58 ± 0.43% drug
diffused after 12 hours. The third approach used was - drug in adhesive based
transdermal drug delivery system. The pressure sensitive adhesive was selected from a
wide range of available marketed pressure sensitive adhesives. DURO-TAK 387-2054 was

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