Cosmetic injectables: a point of difference

By Dr Peter Muzikants and Dr Lesley-Jayne Wild

2007 saw a plethora of new products launched by a few of the established distributors of injectable dermal fillers in Australia. Doctors and clients now have more choices than ever when it’s time to correct that wrinkle, line or enhance your facial features.

The most popular end of the dermal fillers spectrum, the hyaluronic gels, has seen the fiercest marketing competition, not only to the public but also to the cosmetic practitioner. Each new product sounds like the perfect solution to our ageing problems. Each new product claims to be superior to past products and their competitors’ products. We in Australia need to be thankful we have a therapeutic goods regulatory body, the TGA, which has limited the number of competing hyaluronic gels that are available world wide and could otherwise have flooded our country.

How are we as cosmetic industry professionals going to deal with our clients’ enquiries about these new products?

Firstly, let’s look at the new products released this year. These include Juvederm, Esthelis, Restylane ‘Sub-Q’ and Restylane ‘Lipp’. Also due to have been launched just before Christmas is Restylane ‘Vitale’.

It is worth noting that Restylane, until now, has been the most popular hyaluronic gel in Australia. ( Hylaform was the other product available but did not achieve the acceptance among doctors and patients to be a true competitor because of longevity issues).

So, how do these new products stack up against the established leader, Restylane? To be honest, a fair and valid answer to this question would involve a large random double-blinded study. That has not been done and is probably unlikely to eventuate.

We can only look at the differences between the products and try to understand why they are making claims of superiority over their competitors.

Essentially, all hyaluronic gels are built from the same basic sugar polymer molecule, its proper biochemical name being ‘hyaluronic acid.’ This is identical to that which is produced by our own body or by any other animal species as well as by certain bacterial micro-organisms. In fact, the main source of hyaluronic acid for injectable gel is bacteria and therefore of non-animal origin. However, injecting pure hyaluronic gel into skin would not be wise as it would be broken down by our normal skin enzymes within one to two days. So, all the available filler gels have been minimally altered by the addition of very tiny amounts of chemical cross-links to hold the long hyaluron molecules together and slow down the degradation by skin enzymes. Further, this cross-linking can also increase the gel’s ‘hardness’ or ability to flow.

The other feature of the hyaluronic gels that may vary is the gel particle size. During the manufacturing process pure hyaluronic acid powder is reconstituted with water. A gel mass is produced to which cross-links are added, making it a fairly solid mass. This large mass of gel then needs to be prepared so as to be able to be placed into a syringe and injected. Consequently, the solid gel mass with all its cross-linked molecules, is physically broken down into small gel particles – small enough to allow it to behave like liquid and flow through a small needle. This is called ‘sizing’ of hyaluron gel. It may be as simple as forcing the gel mass through a grate or may involve more complex techniques which the manufactures will not divulge because of protection by commercial secrets laws.

The sizing of the hyaluron gel mass will also influence the degradation (breakdown by the body’s enzymes) of the product.

It is argued that larger, cuboidal shaped particles may be more resistant to enzyme attack. This may be the case if there is no movement of the particles (say, in a tear trough) – but in a highly mobile area such as around the mouth and lips where constant movement occurs, one can expect the particles to be eroded by constant collision which allows for easier enzyme attack.

So the main differences between the different hyaluronic gels are, firstly, a function of the degree and type of cross-linking and secondly of the gel particle sizing. Other factors such as concentration of hyaluronic acid and degree of hydration of the gels will also play a role in giving each product their unique properties.

This may sound fairly easy to understand thus far, but it gets more complex and confusing as different products will have different combinations of these features and the comparison on paper becomes more complicated and less predictable. Don’t make the mistake of judging a product on just one of its properties ,for example, the hyaluronic gel ‘concentration’ (see table 1.) A higher hyaluron concentration figure alone does not necessarily imply a superior product.

Other factors require consideration. For example, one product may have a higher concentration of hyaluron, but a lesser amount of cross-linking than its competitors, which may reduce the longevity of the higher-concentrated gel.

Then, of course, we have to look at other factors such as gel particle sizing and the type of cross-link bonds. It is the combination of all these factors, and maybe even more, that will determine the performance of the injectable gel in the skin.

The purpose of this exercise is to demonstrate the complexity of these dermal fillers when trying to predict their clinical properties.

In many cases, clients may be only concerned with longevity of the product. Often then, the idea of a ‘permanent filler’ sounds perfect – but we need to educate our clients that in the real world this is not necessarily the nirvana of fillers. After all, the term “permanent filler’ means, by definition, that it is not biodegradable over time. There are two very good points to bring to your clients’ attention if they insist they are only interested in ‘permanent fillers.’ These are, firstly, our faces are constantly changing over time, and so the corrections required will also change. Secondly, the longer a foreign material sits in the skin, the greater the chance the body will find a way to react to it – possibly resulting in red, swollen lump formation. Remind them that permanent fillers may also mean permanent problems.

On the other hand, the hyaluronic gels are re-sorbable, but they can be considered ‘long term’ fillers as many people will see results lasting more than six months. In my own practice, many areas I treat with hyaluronics see results lasting well over 12 months.

Getting back to the question of which injectable filler is the best, I must disappoint you by not being able to provide an irrefutable answer. As already demonstrated there are many properties of each hyaluonic gel that make each product in some way unique. We need to consider not only longevity of the product, which consumers seem mainly to consider, but we need to assess the suitability of the product. How natural it looks, feels and performs over time in the particular area in which it has been placed is of much consequence.

Restylane appears to be leading the way by introducing many specialised products designed for specific jobs, for example the latest ‘Sub-Q’ for volumising cheeks, ‘Lipp’ for lip enhancement and ‘Vitale’ for those very thin skin areas like the lower eyelids, hands & décolletage. It may make the choices harder for consumers, but from the experienced injector’s point of view it has never been better to have choice. It is far better than having just one or two products to choose from, which any experienced injector worth his/her salt will tell you is simply not enough. Different lines, creases on different parts of face on different skin types all demand particular and different filler properties. The only way to achieve great results is to have available a variety of fillers to meet the demands of multiple conditions.

Finally, the answer to how to find the best injectable filler will come from experienced cosmetic injectors. No matter how impressive the technical figures and claims made by the product manufacturers, it will come down to the empirical data injectors will gather from the clients they treat: longevity, appearance, tactile sensation and side effects. The cosmetic injector is in the front seat to observe these features and to use this information to compare the performance of the different products in the myriad conditions for which they will be used. Your clients’ queries about the latest new filler would be best addressed by discussing this with an experienced cosmetic injector who will assess the problem and match it to the empirical data that he or she has accumulated through clinical experience.

Dr Peter Muzikants and Dr Lesley Wild both graduated from University of NSW medical school with MB, BS in 1984. For the past 20 years they have been specialising in laser and cosmetic medicine and are established in Sydney and Wollongong. Ada Cosmetic Medicine is one of Australia’s largest laser and cosmetic clinics. Their special interests are dermatologic lasers and non-surgical cosmetic procedures.

For further information, contact Ada Cosmetic Medicine: (02) 9552 1442 or visit www.adacosmetic.com.au