ISSN:
1468-3083
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Hyaluronic acid (HA) derivatives have been developed to try to enhance Theological properties of this molecule to make it suitable for various medical applications. The main dermatological application of HA derivatives is the augmentation of soft tissues, via injection into the dermis. HA derivatives are indicated for the correction of cutaneous contour deficiencies of the skin, particularly in cases of ageing or degenerative lesions or to increase lips. Two HA derivatives have been evaluated: Hylaform® Viscoelastic Gel (Hylan B), derived from rooster combs and subjected to cross-linking, and Restylane®, produced through bacterial fermentation (streptococci) and stabilized, as declared by the producer. In both cases the purpose is to improve HA rheological characteristics and slow down its degradation once it is in contact with biological structures. Distribution of particle dimensions, pH, protein concentration and rheological properties have been investigated in order to evaluate their reliability as fillers for soft tissue augmentation. The results of the analyses showed that there are differences between Restylane® and Hylaform®. Especially as far as rheological characteristics are concerned, the results outline different structures of the products: Hylaform® behaves as a strong hydrogel, Restylane® as a weak hydrogel; theologically Hylaform® is clearly superior to Restylane®. Hylaform® contains a definitely minor quantity (about a quarter) of cross-linked hyaluronic acid than Restylane®. Furthermore, although not declared by the manufacturer, Restylane® contains protein, resulting from bacterial fermentation or added to enable cross-linking reaction; the quantity of proteins contained by Restylane® can be as much as four times the quantity contained by Hylaform®, for the same volume (1 ml). It is evident that Hylaform® offers higher safety margin than Restylane®. Furthermore, wide literature and 20 years of clinical experience on hyaluronan derived from rooster combs confirm the reliability of this derivative while we did not find evidence regarding about the safety of HA obtained from streptococcus.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1468-3083.1999.tb00881.x
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