Clay-Based Hydrogels as Drug Delivery Vehicles of Curcumin Nanocrystals for Topical Application

Abstract

The poor water solubility of a significant number of active pharmaceutical ingredients (API) remains one of the main challenges in the drug development process, causing low bioavailability and therapeutic failure of drug candidates. Curcumin is a well-known Biopharmaceutics Classification System (BCS) class IV drug, characterized by lipophilicity and low permeability, which hampers topical bioavailability. Given these premises, the aim of this work was the design and the development of curcumin nanocrystals and their incorporation into natural inorganic hydrogels for topical application. Curcumin nanocrystals were manufactured by the wet ball milling technique and then loaded in clay-based hydrogels. Bentonite and/or palygorskite were selected as the inorganic gelling agents. Curcumin nanocrystal-loaded hydrogels were manufactured by means of a homogenization process and characterized with respect to their chemico-physical properties, in vitro release, antioxidant activity and skin permeation. The results highlighted that the presence of bentonite provided an increase of curcumin skin penetration and simultaneously allowed its radical scavenging properties, due to the desirable rheological characteristics, which should guarantee the necessary contact time of the gel with the skin.

Wondrous Yellow Molecule: Are Hydrogels a Successful Strategy to Overcome the Limitations of Curcumin?

“…Subsequently, the product was analyzed for its topical use. The results of ex vivo experiments indicated improved porcine skin model permeability (with permeation ranging around 40% through the stratum corneum and around 25% through the epidermis) and free radical neutralization (ranging from 40% to 80% depending on the type of the clay) [31]. Similar results were obtained when curcumin nanocrystals were coated with chitosan and further embedded in Carbopol934 hydrogel.…”

“…Many studies have been conducted concerning novel curcumin-hydrogel delivery systems. They are designed to take advantage of curcumin's versatile pharmaceutical potential and hydrogel specific properties while overcoming curcumin's disadvantages such as poor bioavailability and instability (Table 1) [29][30][31]. Many known and novel delivery systems utilizing various releasing modes were used to create a hydrogel base for the curcumin.…”

“…Nano-based oral delivery systems Controlled/prolonged release [30,32] Nano-based topical delivery systems Better skin permeability [31,33] Injectable delivery systems Controlled release [34,35] 2.1. Hydrogels' Releasing Modes for Curcumin Delivery…”

“…Hydrogels were also evaluated for the prolonged release profile of curcumin as topical drug delivery systems. The biggest challenge in the topical delivery of curcumin is its insolubility [31,33]. Hence, curcumin nanocrystal-loaded clay-based hydrogels were prepared by using the wet ball media milling method and mixing formed nanosuspension with clay-based hydrogel.…”

Natural and Synthetic Clay Minerals in the Pharmaceutical and Biomedical Fields

“…PAL and/or bentonite were also used as gelling agents for topical administration of curcumin [ 85 ] or diclofenac [ 86 ] nanocrystals. The wet ball media milling process was used to prepare a curcumin/diclofenac nanosuspension which was then incorporated into clay-based hydrogels using a homogenization process.…”