Part 1. Evaluation of Epigallocatechin Gallate or Tannic Acid Formulations of Hydrophobic Drugs for Enhanced Dermal and Bladder Uptake or for Local Anesthesia Effects

Abstract

Epigallocatechin gallate (EGCG) and tannic acid (TA) are known to increase the aqueous solubility and cellular uptake of the hydrophobic drugs docetaxel, paclitaxel, amphotericin B, and curcumin. In this study the practical application of gallate-based solubilization phenomena for the uptake of these drugs into dermal and bladder tissue and of lidocaine for wound healing application was studied. The penetration of all these drugs into pig skin or docetaxel into pig bladder using EGCG or TA formulations was measured. Overall, EGCG and TA particulate or propylene glycol paste formulations of drugs allowed for greatly increased levels of drug uptake into skin as compared to control formulations. EGCG/propylene glycol pastes allowed for rapid lidocaine uptake into skin. EGCG and TA formulations of docetaxel allowed for approximately 10 fold increases in bladder tissue uptake of docetaxel over tween based solutions. Morphologically, both EGCG and TA caused a mild, dose dependent exfoliation of the bladder wall. Both EGCG and TA formed injectable viscous pastes with propylene glycol which solidified in water and degraded and released lidocaine over 2e35 days. These data support the use of EGCG and TA based formulations of certain drugs for improved dermal, bladder and wound applications.

Tannic acid: a versatile polyphenol for design of biomedical hydrogels

“…42 The large numbers of hydrogen bonds (donor/acceptor sites) and hydrophobic regions of TA allow for the optimal molecular alignment with hydrophobic drugs that have similar characteristics and thereby divest water and prevent precipitation. 43 Paclitaxel, an antineoplastic drug for the treatment of different types of solid tumor cancers, has also been used as a model nano-encapsulation drug through intense intermolecular hydrogen-bonded interactions of TA and polyvinylpyrrolidone (PVP). 44 The physical crosslinking, including strong and weak hydrogen bonding between hydroxyl groups of poly(vinyl alcohol) (PVA) and TA, led to gelation upon mixing at a high temperature, and finally, gelation appeared at room temperature.…”

Synergistic Antibacterial Effects of Gallate Containing Compounds with Silver Nanoparticles in Gallate Crossed Linked PVA Hydrogel Films

“…There are limited studies using EGCG or Quercetin as singular agents directly in PVA films for mechanical or solubilization effects, although Quercetin has been used in PVA in combination with boron [39,40] and used as an antioxidant in PVA for food packaging [41]. The hydrogen bonding potential of Tannic acid and EGCG has been previously noted around drug solubilization of hydrophobic drugs [42][43][44].…”