Toward Physicochemical and Rheological Characterization of Different Injectable Hyaluronic Acid Dermal Fillers Cross-Linked with Polyethylene Glycol Diglycidyl Ether

Abstract

(1) Background: Injectable hyaluronic acid (HA) dermal fillers are used to restore volume, hydration and skin tone in aesthetic medicine. HA fillers differ from each other due to their cross-linking technologies, with the aim to increase mechanical and biological activities. One of the most recent and promising cross-linkers is polyethylene glycol diglycidyl ether (PEGDE), used by the company Matex Lab S.p.A., (Brindisi, Italy) to create the HA dermal filler PEGDE family. Over the last few years, several studies have been performed to investigate the biocompatibility and biodegradability of these formulations, but little information is available regarding their matrix structure, rheological and physicochemical properties related to their cross-linking technologies, the HA content or the degree of cross-linking. (2) Methods: Seven different injectable HA hydrogels were subjected to optical microscopic examination, cohesivity evaluation and rheological characterization in order to investigate their behavior. (3) Results: The analyzed cross-linked dermal fillers showed a fibrous “spiderweb-like” matrix structure, with each medical device presenting different and peculiar rheological features. Except for HA non cross-linked hydrogel 18 mg/mL, all showed an elastic and cohesive profile. (4) Conclusions: The comparative analysis with other literature works makes a preliminary characterization of these injectable medical devices possible.

Clinical Experience with PEGylated Hyaluronic Acid Fillers: A 3-year Retrospective Study

“…PEG is a polymer and can be used as crosslinking agent in order to obtain the so-called PEGylation process. Furthermore, HA is a polymer, the cross-linking effect between PEG and HA create a matrices with scaffold structure, a sort of 3D molecular scaffold, that has a better integration with the host tissue, gaining a long-lasting effect and a better resistance to thermal and mechanical stress [23]. The cross-linking between HA and PEG is characterized by an organic reaction in which an epoxide ring-opening with the hydroxyl group of the HA and the formation of a C-O-C bond, which is among the most stable bonds and consequently is very resistant to degradation.…”

Comparative Physicochemical Analysis among 1,4-Butanediol Diglycidyl Ether Cross-Linked Hyaluronic Acid Dermal Fillers

“…The investigation demonstrates that the organization of microscopic areas of the HA hydrogels do not show remarkable differences among the dermal fillers despite the different concentrations of HA in their composition; rather, they a peculiar and homogenous fibrous matrix structure resembling a “spider web”. Furthermore, previous studies demonstrate that this feature is peculiar of cross-linked HA hydrogels, and it is totally absent in not cross-linked HA dermal fillers that show microelements dispersed flake-like in aqueous solution [ 21 ].…”

“…The HA fillers’ capacity to resist deformation and to spring back (ability to return to the original shape) was demonstrated for these four cross-linked samples. The rheological parameters of a not cross-linked HA dermal filler were investigated in a previous study [ 21 ].…”

Non-Surgical Touch-Up with Hyaluronic Acid Fillers Following Facial Reconstructive Surgery

“…It has become popular to use hyaluronic acid (HA)-based fillers to treat facial wrinkles and deep tissue folds [82]. Their space-filling properties are well described both clinically and histologically [83][84][85][86], and multiple reports demonstrate the positive effects of HAbased fillers on the dermis [83][84][85][86][87][88]. HA filler charming features could be related to the relative ease of application, immediate results, and minimal downtime.…”