Evaluation of the stability of creatine in solution prepared from effervescent creatine formulations

Pharmacokinetic Evaluation of a Single 5-Gram Bolus of Creatine Monohydrate Versus Two Other Creatine-Containing Investigational Products

The purpose of this study was to determine the relative pharmacokinetics of creatine monohydrate delivered as a formula or as a pure powder (all mixed in solution). A single 5 g bolus of creatine monohydrate was ingested as CreaBev 1, CreaBev 2, or creatine monohydrate. Participants we assigned a test product and monitored in a supervised laboratory setting for ingestion and all blood draws starting 30 min post-ingestion to the 6-h mark. Standard pharmacokinetic analysis was undertaken to determine relative maximum concentration (Cmax), time to maximum concentration (Tmax), and area under the curve (AUC) for the products. Cmax data indicate that CreaBev 1 10.55±4.10, CreaBev 2 15.45±5.48, and creatine monohydrate 12.77±4.0 nmol/h/μL. The Tmax analysis demonstrated CreaBev 1 1.20±1.01, CreaBev 2 1.23±0.65, and creatine monohydrate 0.91±0.2 h. The AUC data indicate that CreaBev 1 22.90±9.17, CreaBev 2 33.92±9.52, and creatine monohydrate 29.58±11.93 nmol/h/μL. When examining the data for pharmacokinetics, the AUC and Cmax pharmacokinetics were greatest for CreaBev 2 (p<0.021 and 0.020). Within the confines of this study, CreaBev 2 produced the highest blood concentrations of creatine as compared to creatine monohydrate and CreaBev 1.

The effect of creatine ingestion on urinary creatinine concentration: Does supplementation mask a heavy dilution?

A high volume of fluid can strongly reduce a drug's concentration in urine. Therefore, to detect diluted samples, the concentration of creatinine in urine is determined during testing drugs of abuse. If the concentration is below 20 mg creatinine/dl urine, the urine sample is usually rejected for drug testing. It should be examined whether creatine or creatinine ingestion can mask urine dilution by increasing the creatinine concentration. A total of 18 subjects drank 1.3 L of water and 0.2 L of orange juice on each of the three testing days: (1) without creatine, (2) with 20 g of creatine, and (3) with 20 g of creatine following incubation for 4 days in orange juice at room temperature; an acidic environment should promote conversion of creatine to creatinine. The lowest creatinine concentrations in urine were observed on average 2 h after fluid intake. At that time, ingestion of fluid without creatine, with creatine, and with creatine(ine)-orange juice mixture resulted in mean values of 11.6, 22.5, and 28.3 mg creatinine/dl urine, respectively. It can be concluded that ingestion of creatine or creatinine can increase the concentration of creatinine in urine and thus mask dilution of a sample. The conversion of creatine in orange juice further increases availability of creatinine as it is obvious from urine creatinine concentration. Therefore, creatine ingestion during drug testing will give rise to negative results due to matrix adulteration. In a case of suspected creatine supplementation, the creatine content of the sample should be determined in addition to creatinine.

Experimental and computational study of guanidinoacetic acid self-aggregation in aqueous solution

In this work for the first time the physicochemical and thermal properties of guanidinoacetic acid (GAA) and its aqueous solutions have been performed to test for its viability as a potential dietary supplement. Thermal stability, viscosity, solubility and experimental density are determined. From measured densities the volumetric properties were estimated and discussed in the scope of GAA self-aggregation in aqueous solutions using experimental and computational results. Based on thermal stability and solubility measurements, it is found that GAA is more thermally stable but less soluble comparing to creatine due to a self-aggregation process that occurs at GAA concentrations higher than 0.013mol·dm^-3. Existence of self-aggregation influences the macroscopic properties of aqueous GAA solutions, but also its bioavailability.

Creatine and creatine forms intended for sports nutrition

Creatine is a popular ergogenic supplement in sports nutrition. Yet, supplementation of creatine occasionally caused adverse effects such as gastrointestinal complaints, muscle cramps and an increase in body weight. Creatine monohydrate has already been evaluated by different competent authorities and several have come to the conclusion that a daily intake of 3 g creatine per person is unlikely to pose safety concerns, focusing on healthy adults with exclusion of pregnant and breastfeeding women. Possible vulnerable subgroups were also discussed in relation to the safety of creatine. The present review provides an up-to-date overview of the relevant information with special focus on human studies regarding the safety of creatine monohydrate and other marketed creatine forms, in particular creatine pyruvate, creatine citrate, creatine malate, creatine taurinate, creatine phosphate, creatine orotate, creatine ethyl ester, creatine pyroglutamate, creatine gluconate, and magnesium creatine chelate. Limited data are available with regard to the safety of the latter creatine forms. Considering an acceptable creatine intake of 3 g per day, most of the evaluated creatine forms are unlikely to pose safety concerns, however some safety concerns regarding a supplementary intake of creatine orotate, creatine phosphate, and magnesium creatine chelate are discussed here.

Spectroscopic and structural study of the newly synthesized heteroligand complex of copper with creatinine and urea

Study of copper complex of creatinine and urea is very important in life science and medicine. In this paper, spectroscopic and structural study of a newly synthesized heteroligand complex of copper with creatinine and urea has been discussed. Structural studies have been carried out using DFT calculations and spectroscopic analyses were carried out by FT-IR, Raman, UV-vis absorption and fluorescence techniques. The copper complex of creatinine and the heteroligand complex were found to have much increased water solubility as compared to pure creatinine. The analysis of FT-IR and Raman spectra helps to understand the coordination properties of the two ligands and to determine the probable structure of the heteroligand complex. The LIBS spectra of the heteroligand complex reveal that the complex is free from other metal impurities. UV-visible absorption spectra and the fluorescence emission spectra of the aqueous solution of Cu-Crn-urea heteroligand complex at different solute concentrations have been analyzed and the complex is found to be rigid and stable in its monomeric form at very low concentrations.

Temperature dependent Raman and DFT study of creatine

Temperature dependent Raman spectra of creatine powder have been recorded in the temperature range 420-100K at regular intervals and different clusters of creatine have been optimized using density functional theory (DFT) in order to determine the effect of temperature on the hydrogen bonded network in the crystal structure of creatine. Vibrational assignments of all the 48 normal modes of the zwitterionic form of creatine have been done in terms of potential energy distribution obtained from DFT calculations. Precise analysis gives information about thermal motion and intermolecular interactions with respect to temperature in the crystal lattice. Formation of higher hydrogen bonded aggregates on cooling can be visualized from the spectra through clear signature of phase transition between 200K and 180K.

A buffered form of creatine does not promote greater changes in muscle creatine content, body composition, or training adaptations than creatine monohydrate

Background

Creatine monohydrate (CrM) has been consistently reported to increase muscle creatine content and improve high-intensity exercise capacity. However, a number of different forms of creatine have been purported to be more efficacious than CrM. The purpose of this study was to determine if a buffered creatine monohydrate (KA) that has been purported to promote greater creatine retention and training adaptations with fewer side effects at lower doses is more efficacious than CrM supplementation in resistance-trained individuals.

Methods

In a double-blind manner, 36 resistance-trained participants (20.2 ± 2 years, 181 ± 7 cm, 82.1 ± 12 kg, and 14.7 ± 5% body fat) were randomly assigned to supplement their diet with CrM (Creapure® AlzChem AG, Trostberg, Germany) at normal loading (4 x 5 g/d for 7-days) and maintenance (5 g/d for 21-days) doses; KA (Kre-Alkalyn®, All American Pharmaceutical, Billings, MT, USA) at manufacturer’s recommended doses (KA-L, 1.5 g/d for 28-days); or, KA with equivalent loading (4 x 5 g/d for 7-days) and maintenance (5 g/d) doses of CrM (KA-H). Participants were asked to maintain their current training programs and record all workouts. Muscle biopsies from the vastus lateralis, fasting blood samples, body weight, DEXA determined body composition, and Wingate Anaerobic Capacity (WAC) tests were performed at 0, 7, and 28-days while 1RM strength tests were performed at 0 and 28-days. Data were analyzed by a repeated measures multivariate analysis of variance (MANOVA) and are presented as mean ± SD changes from baseline after 7 and 28-days, respectively.

Results

Muscle free creatine content obtained in a subgroup of 25 participants increased in all groups over time (1.4 ± 20.7 and 11.9 ± 24.0 mmol/kg DW, p = 0.03) after 7 and 28-days, respectively, with no significant differences among groups (KA-L −7.9 ± 22.3, 4.7 ± 27.0; KA-H 1.0 ± 12.8, 9.1 ± 23.2; CrM 11.3 ± 23.9, 22.3 ± 21.0 mmol/kg DW, p = 0.46). However, while no overall group differences were observed (p = 0.14), pairwise comparison between the KA-L and CrM groups revealed that changes in muscle creatine content tended to be greater in the CrM group (KA-L −1.1 ± 4.3, CrM 11.2 ± 4.3 mmol/kg DW, p = 0.053 [mean ± SEM]). Although some significant time effects were observed, no significant group x time interactions (p > 0.05) were observed in changes in body mass, fat free mass, fat mass, percent body fat, or total body water; bench press and leg press 1RM strength; WAC mean power, peak power, or total work; serum blood lipids, markers of catabolism and bone status, and serum electrolyte status; or, whole blood makers of lymphocytes and red cells. Serum creatinine levels increased in all groups (p < 0.001) with higher doses of creatine promoting greater increases in serum creatinine (p = 0.03) but the increases observed (0.1 – 0.2 mg/dl) were well within normal values for active individuals (i.e., <1.28 ± 0.2 mg/dl). Serum LDL was decreased to a greater degree following ingesting loading doses in the CrM group but returned to baseline during the maintenance phase. No side effects were reported.

Conclusions

Neither manufacturers recommended doses of KA (1.5 g/d) or KA with equivalent loading (20 g/d for 7-days) and maintenance doses (5 g/d for 21-days) of CrM promoted greater changes in muscle creatine content, body composition, strength, or anaerobic capacity than CrM (20 g/d for 7-days, 5 g/d for 21-days). There was no evidence that supplementing the diet with a buffered form of creatine resulted in fewer side effects than CrM. These findings do not support claims that consuming a buffered form of creatine is a more efficacious and/or safer form of creatine to consume than creatine monohydrate.

Creatine supplementation with specific view to exercise/sports performance: an update

Creatine is one of the most popular and widely researched natural supplements. The majority of studies have focused on the effects of creatine monohydrate on performance and health; however, many other forms of creatine exist and are commercially available in the sports nutrition/supplement market. Regardless of the form, supplementation with creatine has regularly shown to increase strength, fat free mass, and muscle morphology with concurrent heavy resistance training more than resistance training alone. Creatine may be of benefit in other modes of exercise such as high-intensity sprints or endurance training. However, it appears that the effects of creatine diminish as the length of time spent exercising increases. Even though not all individuals respond similarly to creatine supplementation, it is generally accepted that its supplementation increases creatine storage and promotes a faster regeneration of adenosine triphosphate between high intensity exercises. These improved outcomes will increase performance and promote greater training adaptations. More recent research suggests that creatine supplementation in amounts of 0.1 g/kg of body weight combined with resistance training improves training adaptations at a cellular and sub-cellular level. Finally, although presently ingesting creatine as an oral supplement is considered safe and ethical, the perception of safety cannot be guaranteed, especially when administered for long period of time to different populations (athletes, sedentary, patient, active, young or elderly).

Analysis of the efficacy, safety, and regulatory status of novel forms of creatine

Creatine has become one of the most popular dietary supplements in the sports nutrition market. The form of creatine that has been most extensively studied and commonly used in dietary supplements is creatine monohydrate (CM). Studies have consistently indicated that CM supplementation increases muscle creatine and phosphocreatine concentrations by approximately 15–40%, enhances anaerobic exercise capacity, and increases training volume leading to greater gains in strength, power, and muscle mass. A number of potential therapeutic benefits have also been suggested in various clinical populations. Studies have indicated that CM is not degraded during normal digestion and that nearly 99% of orally ingested CM is either taken up by muscle or excreted in urine. Further, no medically significant side effects have been reported in literature. Nevertheless, supplement manufacturers have continually introduced newer forms of creatine into the marketplace. These newer forms have been purported to have better physical and chemical properties, bioavailability, efficacy, and/or safety profiles than CM. However, there is little to no evidence that any of the newer forms of creatine are more effective and/or safer than CM whether ingested alone and/or in combination with other nutrients. In addition, whereas the safety, efficacy, and regulatory status of CM is clearly defined in almost all global markets; the safety, efficacy, and regulatory status of other forms of creatine present in today’s marketplace as a dietary or food supplement is less clear.

Kinetics of creatine ingested as a food ingredient

The aim of the present study was to test if the consumption of creatine incorporated in food bars modifies creatine plasma kinetics, erythrocyte retention and loss in urine and in feces when compared with its consumption in the form of an aqueous solution (AS). Seventeen healthy young men ingested 2 g creatine either in the form of AS, or incorporated in a protein (PP)- or in a beta-glucan (BG)-rich food bar. Kinetics of plasma creatine was measured for 8-h duration and urinary excretion for 24 h. Then, the subjects received the same treatment thrice a day for 1 week at the end of which creatine contents were determined in erythrocytes and in feces (n = 4 for feces). The three crossover treatments were interspaced by a 40 +/- 1.2-day wash-out. Absorption of creatine was slowed down by 8-fold in the presence of BG (P < 0.001) and by 4-fold with PP (P < 0.001) whereas the velocity rate constant of elimination and the area under the curve were not modified. Urinary loss of creatine in the first 24 h following ingestion was 15 +/- 1.9% in AS and 14 +/- 2.2% in PP conditions (NS), whereas it was only 8 +/- 1.2% with BG (P = 0.004). Increase in creatine concentration in erythrocyte was similar in whatever form the creatine was ingested. Creatine seems to be totally absorbed since no creatine or creatinine was detectable in feces. No side effects were reported. In conclusion, ingestion of creatine combined with BG facilitates its retention by slowing down its absorption rate and reducing its urinary excretion.