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THERMODYNAMIC PROPERTIES OF OCULAR PERMEATION OF DICLOFENAC: EFFECT OF TRIETHANOLAMINE

RAJARAM MOHAPATRA, SIBANANDA SENAPATI, CHINMAYA SAHOO, SUBRATA MALLICK^*

Department of Pharmaceutics, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan University, Khandagiri Square, Bhubaneswar, OR, India

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The objective of the present study was to evaluate the effect of triethanolamine (TEA) as plasticizer on the thermodynamic properties of ex-vivo permeation of diclofenac potassium (DP) from hypromellose matrix films. The apparent permeability has been evaluated at different temperatures and utilized for estimation of activation energy (Ea), enthalpy (ΔH), entropy (ΔS) and free energy (ΔG) of permeation, diffusion and partition. Permeation was found to be increasing with the increase of temperature and concentration of plasticizer. Improved permeation has been supported by the decreased value of activation energy. Positive ΔH value of all the films indicated increased permeation with the increase of temperature. The presence TEA in the formulation significantly lowered the ΔS value compared to the film without TEA. FTIR, DSC and SEM studies of the films revealed the inhibition of the crystal growth and transformation of crystalline nature of drug to amorphous state. The film (containing 30% TEA) was rehydrated in vivo upon lachrymal fluid uptake and progressed as a bioerodible swelled mass at the end of 5 h of application.