Now that I'm acquainted with the patent field, however, I'm aware that just about anything can be patented, provided that the "thing" is useful, novel, nonobvious, and complies with various other statutory requirements. There is no requirement, however, to prove that the invention actually works as asserted, nor that the product is "better" in any way than other products intended to be used for the same purpose. A patent just means that the Examiner at the US Patent Office took no issue with the asserted utility of the invention, and the Examiner couldn't find any prior art (i.e., references) that disclosed or suggested the claimed invention. Pretty much end of story.
Enter CeraVe®. You must've seen the TV commercials by now for the CeraVe® skin products that claim to be based on a "unique, patented Multivesicular Emulsion (MVE®) delivery technology." When I first saw this, my first impression was "oooh, that sounds cool, it must really work and stuff." Then my brain kicked in and said "hmmm, that marketing campaign must snare lots of customers." I googled CeraVe® and they have a section of their website that gets all scientific about what their products contain, how they work, and mentions their patented MVE® delivery system a few times.
Now, I'm not saying CeraVe® products don't work - in fact they may work exactly as marketed and described on their website - I'm just pointing out that whenever you see a product marketed as "patented," you should be a little skeptical and remind yourself that "patented" does not necessarily mean that the product actually works or is superior to others on the market. CeraVe® just happens to be the most recent chemical case of a product having this type of marketing campaign, and therefore I'm using this situation as an example. (Disclaimer: I have not evaluated the CeraVe® product in any way and cannot speak to the effectiveness of the product).
Quite surprisingly, despite the fact that CeraVe® repeatedly mentions their patented MVE® delivery system on their website and in their commercial, I could not find on their website any reference to the actual patent protecting their invention, even when trying a Google site search. I can only speculate as to the reasons. Luckily, however, there is only one patent I could find assigned to Healthpoint, Ltd. (the owner of the trademark MVE® noted on CeraVe®'s website) that contains the word "multivesicular," and that is U.S. Patent 6,709,663 titled "Multivesicular Emulsion Drug Delivery Systems."
Ok, enough warning you about products marketed as "patented." Let's get into the science of the CeraVe® multivesicular emulsion delivery system! So, what's the gist of the patent? Well, it notes there is a problem with the release rate of most conventional products that are based on regular, single-walled vesicles (i.e., those that are not multi-walled vesicles). Specifically, conventional products, once applied to the skin, allegedly have a "spike" in the release of the active agents contained in the vesicles, which can cause overdosing and skin irritation at the point of application. In contrast, the MVE® delivery system allegedly has sustained release over a longer period of time, such that overdosing and skin irritation are reduced or eliminated. The patent also notes that the inventive composition affects the biophysical properties of the skin, such as increased blood flow, reduction of transepidermal water loss, and increase of skin hydration.
What exactly is a "multivesicular emulsion" anyways? The patent defines it as an emulsion comprising vesicles having a series of concentric spheres or shells of oil and water phases, and states that under a microscope, the vesicles looks very similar to the cross section of an onion. Given this definition, it seems that "multivesicular emulsion" is really just this patent's fancy name for multilamellar emulsions (MLEs) or multilamellar vesicles (MLVs), which are the more generally accepted terms in the field.
The multivesicular emulsion is prepared by mixing an active agent with either water or oil, whichever phase it is most compatible with, and then a quaternary ammonium salt emulsifier is added at a preferred level of 0.5-5 wt.%. The mixture is then high sheer mixed and the active agent becomes trapped within the concentric walls of the multi-layered vesicles. The resulting emulsion is said to be an oil-in-water emulsion, which makes sense given that the emulsifier is positively charged and thus likely water soluble (or at least more compatible with water than oil).
The active agent can include a variety of compounds, such as those effective against acne, hair growth, canker sores, dry skin, wound treatment, among many others. The emulsifier is a quaternary amine salt derived from colza (rapeseed) oil. The patent states that the preferred emulsifier is behentrimonium methosulfate (see structure at right), though it lists other salts of behentrimonium to be suitable as well, such as the choride, sulfuate, and ethosulfate salts. The preferred source of behentrimonium methosulfate is the commercial product Incroquat® Behenyl TMS, which comes formulated as a mixture of behentrimonium methosulfate (25%) and cetearyl alcohol (75%), another known emulsifier, which results in cetearyl alcohol turning up in most, if not all, of the formulations listed in the patent.
It appears that the multi-walled structure of the multivesicular emulsion is the cause of the sustained release characteristics of the CeraVe® products. In an example in the patent, the release rate of an anti-fungal drug (econazole nitrate) from the inventive multi-layered vesicles was compared with the release rate of the same anti-fungal drug from the commercial product Spectazole from Johnson & Johnson, which likely is an emulsion of single-walled vesicles. The release rates are compared in the graph to the left. The patent states that "[t]he results of the diffusion test revealed that there was sustained release over a period of time for the multivesicular emulsion of the present invention, but there was a spike release of short duration for the Spectazole." I don't know if I'd characterize the Spectazole trace as a "spike," since the Spectazole trace doesn't start peeling away from the sheet cream trace until about 225 minutes (15 min squared = 3.75 hrs), but clearly the inventive sheer cream does appear to have a lower release rate and thus more sustained release over time.
The patent lists a variety of specific compositions for various products, including a gentle cleanser, sunscreen lotion, ceramide cream, self tanning cream, diaper rash cream, etc. See the patent at columns 6-7 for all the specific formulations. I'll focus on the ceramic cream formulation shown on the right, since this seems to be the most relevant to the CeraVe® product featured in the TV commercial.
The Incroquat Behenyl TMS comprises the emulsifier behentrimonium methosulfate that was mentioned above. Cetyl and stearyl alcohols are surfactants, emulsifiers, and/or emulsion stabilizing compounds. Cetiol LC, butylene glycol, and Crodamol OHS are emollients. Germall must be a biocide to prevent bacterial growth. Rovisome ACE is an antioxidant and UV protectant. Ceramide 2 is a skin conditioner. The remaining ingredients, like sesame oil, macadamia nut oil, avocadin, and peach kernal extract are the fancy "natural" ingredients that may have some real world function in the composition, though may also provide merely a psychological effect for the consumer.
Notably, you'll find two ingredients missing from this list in the patent - niacinamide and hyaluronic acid - two of the ingredients featured in the sciency section of CeraVe®'s website. Actually, I can't find either of these ingredients explicitly mentioned anywhere in the patent. Chances are (though I'm just speculating here) that the inventors of MVE® did not envision, at the time of the invention, employing niacinamide and hyaluronic acid in the compositions. Otherwise, they most certainly would have described these ingredients in the patent. At some later date, however, perhaps it was realized that these two ingredients would work well in a moisturizer cream and/or with the MVE® delivery system.
The composition claim (claim 1) in the patent is fairly broad, and minimally requires a multivesicular emulsion consisting essentially of 0.1-30 wt.% of behentrimonium methosulfate and an active agent trapped within the vesicles, in which the emulsion is a two-phase oil-in-water emulsion and has concentric spheres of oil and water.
The "consisting essentially of" transitional phrase has legal meaning in patent law and limits the scope of the claim to the specified materials and those that do not materially affect the basic and novel characteristics of the claimed invention. So, for example, if a potential infringer added a small amount of dye to the composition of claim 1 of this patent, and the presence of the dye did not affect the basic and novel characteristics of the claimed invention, then the potential infringer would infringe the patent. If, however, a potential infringer added a chemical compound to the claimed composition that made the vesicles infinitely stable, such that the active agents remained encapsulated in the vesicles forever after skin application (under normal conditions), then arguably the potential infringer would not be infringing the patent, since the novel characteristic of "sustained release" would not be present.