Aquamid®

11 Aquamid®





During the past two decades, the improvement and increase in the number of newly available fillers have made soft tissue augmentation with injectable fillers a standard clinical approach to correct wrinkles and folds. With the growing demand of patients for facial rejuvenation and the increasing trend for volumetric enhancement in recent years, the search for longer lasting fillers continues.


Permanent fillers are still demonized with horrendous side effects attributed to them. As new fillers come to the market, we have seen others that have been retired. All fillers, whether permanent or temporary, may create a challenge for successful treatment. Notwithstanding current improvements in the safety, efficacy, and duration of effect of soft tissue fillers, there is still considerable need for a filler that is truly long lasting.



Product


Aquamid® is a non-absorbable soft volume filler for aesthetic and reconstructive purposes. The polyacrylamide hydrogel (PAAG) Aquamid® is one of the new macromolecules that are used as implants and tissue fillers in reconstruction and aesthetic dermatology. Aquamid® hydrogel is a 2.5% cross-linked PAAG made from acrylamide and N,N′-methylene-bis-acrylamide, ammonium persulphate/tetramethyl ethylenediamine (AMPS / TEMED) redox initiator system, and 97.5% purified water. It is not biodegradable and offers a long-lasting effect. Each batch is analyzed for consistency and compliance with product specification, including narrow tolerances of elasticity modulus, pH and impurities, and degradation products from the polymerization reaction. Aquamid® is developed, produced, and commercialized by Contura International A/S, Søborg, Denmark. It was approved and CE marketed in Europe in 2001 for facial augmentation and minor body contouring and is available in more than 40 countries worldwide in Europe, Asia, the Middle East, and Latin America.


Aquamid® has been evaluated in clinical trials by Von Buelow and colleagues, Christensen et al, Narins et al, and Wolter & Pallua, involving more than 5000 patients including a comparative trial in the USA. Data from these trials have been used to support a PMA application to the US Food and Drug Administration (FDA). Aquamid® is not yet approved for sale in the USA, but is expected to get FDA approval by the end of this year.


Studies by Bello and colleagues and by De Cassias Novaes & Berg have shown that this PAAG does not migrate within the tissue after subcutaneous injection because of its large molecular size and high cohesive properties. Christensen found that cells grew well in the Aquamid® gel, which allows vessel ingrowth from adjacent tissue. It is kept in place by means of a fibrous capsule (endoprosthesis) that develops after being injected in the subcutaneous tissue. These capsules are surrounded by fibroblasts and macrophages (Fig. 11.1). Another study by Zarini and colleagues emphasized the importance of the microstructure and porosity of hydrogels in relation to their functions and interactions with surrounding medium and tissue. Hydrogels could behave as an accessible foreign body that creates the appearance of infections that are untreatable. PAAG can exchange both physiological and non-physiological constituents very efficiently with the surrounding medium. In the context of hydrogels as tissue fillers, Brahm et al considered the ability of water and solutes (including an antibiotic) to cross between the hydrogel and the surrounding tissue to be attractive.



The hydrogel is homogeneous, containing no microparticles or microspheres, and its filling effect is immediate. It relies exclusively on adding volume from the gel itself, unlike tissue fillers that are particle based and depend on foreign-body reaction to achieve the desired effect.




Mar 12, 2016 | Posted by in General Surgery | Comments Off on Aquamid®

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