Multifunctional low temperature-cured PVA/PVP/citric acid-based hydrogel forming microarray patches: Physicochemical characteristics and hydrophilic drug interaction

The characteristics of multifunctional polymeric hydrogel-forming microarray patches based on poly(vinyl alcohol)/poly(vinylpyrrolidone)/citric acid composite crosslinked at 80 °C were investigated. The swelling study showed that this composite possesses a higher swelling degree than the same polymer heated at 130 °C due to a lower crosslink density, which was then confirmed by FTIR examination. Solid-state studies revealed that lower-temperature crosslinking does not provide enough energy for the polymer to rearrange itself into a crystalline form. However, this composite polymer was shown to possess acceptable mechanical strength to insert/penetrate into the skin.

Highlights

• Fabrication of low temperature cured PVA/PVP/CA was successfully carried out with satisfactory mechanical properties.
• Diffusion coefficient could potentially be used to predict the permeation patterns of the drug integrated with HF-MAPs.
• The PVA/PVP/CA HF-MAPs can be used both as therapeutic drug monitoring and drug delivery platform.

The patch can function both as a means to sample model hydrophilic drugs from the skin and to deliver them when combined with a melt-type polyethylene glycol reservoir. The hydrophilic interaction between the hydrogel and drugs was investigated. A drug with a higher diffusion coefficient, modelled by theophylline (diffusion coefficient = 16.17 × 10^-6 cm²/s), can be delivered more efficiently than fluorescent sodium (diffusion coefficient = 2.32 × 10^-6 cm²/s) or cyanocobalamin (diffusion coefficient = 7.31 × 10^-6 cm²/s). This is mainly due to theophylline’s high permeability (permeability coefficient = 7.40 × 10^-5 cm/s) and weak ability to interact with the hydrogel (coefficient of partitioning = 1.3). These results indicated that the diffusion coefficient could be a useful predictive parameter to determine the delivery efficiency of the system. Furthermore, the results provide insight into how to select a suitable hydrogel for drug monitoring or delivery involving hydrophilic compounds based on the hydrophilic interaction between the polymer and the drug.

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2.1. Chemicals

The chemicals used in this study were theophylline, fluorescein sodium, PVA 87–89 % hydrolysed MW 85.000–124.000, anhydrous citric acid, methanol for HPLC, acetonitrile for HPLC, triethylamine, and phosphate buffer saline (PBS) tablets (pH 7.4, ionic strength 0.01 M) were purchased from Sigma Aldrich, Dorset, UK. Cyanocobalamin was purchased from Alfa Aesar, Heysham, UK. Plasdone®/PVP K-29/32 was purchased from Ashland, Kidderminster, UK. Water for the formulation, buffer solution, and HPLC was obtained from an ELGA Purelab Flex 2® ultrapure water purification system purchased from Vivendi Water System Ltd., Bucks, UK. Full-thickness skin samples were excised from the stillborn piglets.

Achmad Himawan, Qonita Kurnia Anjani, Usanee Detamornrat, Lalitkumar K. Vora, Andi Dian Permana, Rand Ghanma, Yara Naser, Dina Rahmawanty, Christopher J. Scott, Ryan F. Donnelly, Multifunctional low temperature-cured PVA/PVP/citric acid-based hydrogel forming microarray patches: Physicochemical characteristics and hydrophilic drug interaction, European Polymer Journal, Volume 186, 2023, 111836, ISSN 0014-3057,
https://doi.org/10.1016/j.eurpolymj.2023.111836.