Miller Con-cret Solubility Study
A letter to the owner of Vireo systems inc
Donald W. Miller, Ph.D.
Department of Pharmacology and Therapeutics
University of Manitoba
Dear Mr. Faulkner:
As requested, I have performed the creatine aqueous solubility study comparing creatine monohydrate to creatine hydrochloride (Con-CretTM). As an inventor of creatine hydrochloride, my laboratory had previously demonstrated the superior aqueous solubility properties of the hydrochloride salt form. This data was included in the patent application which was recently evaluated and upon which a patent was issued (USP #7,608,641).
In these studies my laboratory had performed a saturation solubility study in which an excess amount of the various creatine salt forms are added to an aqueous solution. The mixtures are left over night at room temperature and then sampled, filtered to remove any particulate and/or precipitate, and then analyzed via high performance liquid chromatography (HPLC). Our studies suggested that the creatine hydrochloride salt had the best aqueous solubility of all the creatine salts examined (included creatine monohydrate, creatine citrate and creatine pyruvate salts).
While these studies were in good agreement with your own solubility studies performed by the titration method, you requested that we confirm your results, independently in our own laboratory. Thus we have repeated the aqueous solubility studies using the titration methodology which you employed and provided. These studies are summarized below, and the raw data included with this communication.
To reproduce your previous experiments, studies were performed at 60O F using the microcrystalline creatine monohydrate; standard creatine monohydrate and creatine hydrochloride. Mixtures were stirred at a rate of 100 rpm with magnetic stir plate and 2 minutes for each titration. Under these conditions the following was observed:
Microcrystalline Creatine monohydrate: Aqueous solubility 17 + 1 mg/ml
Standard Creatine monohydrate: Aqueous solubility 13 + 1 mg/ml
Creatine hydrochloride: Aqueous solubility 900 + 11 mg/ml
This represents a 53 and 68-fold increase in aqueous solubility for creatine hydrochloride salt compared to microcrystalline and standard creatine monohydrate, respectively.
I have attached the excel spreadsheet of the raw data for your files.