Comparative Physical Properties of Hyaluronic Acid Dermal Fillers
ABSTRACT Hyaluronic acid (HA) fillers are becoming the material of choice for use in cosmetic soft tissue and dermal correction. HA fillers appear to be similar, but their physical characteristics can be quite different. These differences have the potential to affect the ability of the physician to provide the patient with a natural and enduring result.
The objective of this article is to discuss the key physical properties and methods used in characterizing dermal fillers. These methods were then used to analyze several well-known commercially available fillers.
Analytical methods were employed to generate data on the properties of various fillers. The measured physical properties were concentration, gel-to-fluid ratio, HA gel concentration, degree of HA modification, percentage of cross-linking, swelling, modulus, and particle size.
The results demonstrated that commercial fillers exhibit a wide variety of properties.
Combining the objective factors that influence filler performance with clinical experience will provide the patient with the optimal product for achieving the best cosmetic result. A careful review of these gel characteristics is essential in determining filler selection, performance, and patient expectations.
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- "DiHA formed by the degradation of HA with chondroitinase AC. cross-linking efficiency in BDDE cross-linked HA hydrogels, based on the chromatographic separation of polysaccharides formed by mild hydrolysis in alkaline conditions, was reported (Guarise, Pavan, Pirrone, & Renier, 2012). Enzymatic treatment with hyaluronidase of HA hydrogels cross-linked with BDDE (Kablik et al., 2009) and divinylsulfone (Chang et al., 2007) into oligosaccharides prior to chromatographic separation has also been described. A disadvantage with mild hydrolysis and hyaluronidase treatment of HA is that the degradation product consists of a complex mixture of larger oligosaccharides (>tetrasaccharides) making it difficult for a detailed analysis of the cross-linked residues. "
ABSTRACT: Definitions and methods for the quantification of degree of modification and cross-linking in cross-linked hyaluronic acid (HA) hydrogels are outlined. A novel method is presented in which the HA hydrogel is degraded by the enzyme chondroitinase AC and the digest product analyzed by size exclusion chromatography combined with electrospray ionization mass spectrometry (SEC-ESI-MS). This method allows for the determination of effective cross-linker ratio (CrR) which together with the degree of modification (MoD), determined by, e.g. (1)H NMR spectroscopy, enables the calculation of the degree of substitution (DS) and degree of cross-linking (CrD). The method, could be applicable to the major cross-linked HA hydrogels currently on the market, and is exemplified here by application to two HA hydrogels. The definitions and methods presented are important contributions in attempts to find relationships between MoD, DS and CrD to mechanical properties as well as to biocompatibility of HA hydrogels.01/2013; 91(1):410-8. DOI:10.1016/j.carbpol.2012.08.066
Article: Soft Tissue Fillers in the Nose[Show abstract] [Hide abstract]
ABSTRACT: Using soft tissue fillers to correct postrhinoplasty deformities in the nose is appealing. Fillers are minimally invasive and can potentially help patients who are concerned with the financial expense, anesthetic risk, or downtime generally associated with a surgical intervention. A variety of filler materials are currently available and have been used for facial soft tissue augmentation. Of these, hyaluronic acid (HA) derivatives, calcium hydroxylapatite gel (CaHA), and silicone have most frequently been used for treating nasal deformities. While effective, silicone is known to cause severe granulomatous reactions in some patients and should be avoided. HA and CaHA are likely safer, but still may occasionally lead to complications such as infection, thinning of the skin envelope, and necrosis. Nasal injection technique must include sub-SMAS placement to eliminate visible or palpable nodularity. Restricting the use of fillers to the nasal dorsum and sidewalls minimizes complications because more adverse events occur after injections to the nasal tip and alae. We believe that HA and CaHA are acceptable for the treatment of postrhinoplasty deformities in carefully selected patients; however, patients who are treated must be followed closely for complications. The use of any soft tissue filler in the nose should always be approached with great caution and with a thorough consideration of a patient's individual circumstances.Aesthetic surgery journal / the American Society for Aesthetic Plastic surgery 11/2009; 29(6):477-84. DOI:10.1016/j.asj.2009.09.002 · 2.03 Impact Factor