A preliminary investigation into the use of amino acids as potential ion pairs for diclofenac transdermal delivery

Cristofoli, Mignon, Hadgraft, Jonathan, Lane, Majella E. and Sil dos Santos, Bruno (2022) A preliminary investigation into the use of amino acids as potential ion pairs for diclofenac transdermal delivery. International journal of pharmaceutics, 623 (121906). pp. 1-8. ISSN 0378-5173

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Abstract / Description

Ion pairing is a potential strategy used to increase the partition and permeation of ionisable drug molecules. This work outlines the process of identifying, selecting and testing potential counter ions for diclofenac (DF). Three screening criteria were considered in the initial selection process. The first, toxicity, was used to eliminate counter ion candidates that could not be used in topical formulations. The second related to the balancing of charges. As DF is a free acid in its unionised state, counter ions should be of a basic character. Finally, molecular size, as represented by molecular mass (Da), was used. Because of the impact on ion pair formation, the counter ion was required to have a lower molecular weight than diclofenac. Basic amino acids L-Arginine, L-Histidine, L-Lysine and their salts were chosen. The selection process concluded with Partition Coefficient (PC) studies. These were used to identify any counter ions able to interact electrostatically with the ionised DF, enabling the ‘neutral’ ion pair to partition from an aqueous into an organic layer. Permeation studies using porcine skin were performed to test the efficacy of any selected counter ion. These preliminary studies suggest that amino acids may be used as counter ions to increase the partition and permeation of ionisable drugs.

Item Type:	Article
Uncontrolled Keywords:	ion pairs; diclofenac; diclofenac sodium; amino acids; partition coefficient studies; porcine skin; permeation; mass balance
Subjects:	500 Natural Sciences and Mathematics > 540 Chemistry & allied sciences 600 Technology > 610 Medicine & health
Department:	School of Human Sciences
Depositing User:	Bruno Da Silva sil dos santos
Date Deposited:	27 Jun 2022 10:41
Last Modified:	30 Nov 2022 12:48
URI:	https://repository.londonmet.ac.uk/id/eprint/7781

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