The beneficial effects of CBD are well known, including pain relief, anti-anxiety, anti-seizure, anti-depressant, anti-oxidant, and anti-inflammatory activity. Despite much scientific evidence in support of these notions, there is still some inconsistency in the results. The discrepancies may be explained by differences in CBD bioavailability when administered orally.
CBD bioavailability is the proportion of CBD that enters the circulation when introduced into the body, and the only proportion that has an active effect. From previous research including animal studies, the oral bioavailability of CBD is very low (13–19%). Unfortunately, it undergoes extensive first-pass metabolism and its metabolites are mostly excreted through the kidneys.
The inconsistencies can also be explained by the non-standardized CBD formulation, body size, and composition of the consumer. When it comes to formulations, the differences in results might be explained by the difference between water and lipid solubility. It is known that bioavailability is increased with various lipid formulations. Similar to the tips for administrating CBD, with eating more fats just before the ingestion. Also, the overall bioavailability can depend on the time and the type of administration – whether CBD has been consumed as food or a beverage, has it been co-administrated with additional ingredients or preparation as a ready-made product or has it been in a form of a powder to be mixed with liquid by the consumer before ingestion.
Even when once ingested, the resulting circulating CBD concentration is influenced by rates of absorption from the gut, breakdown during the first-pass metabolism, and potentially by the body size and composition of the consumer.
Analysis critical to the therapeutic use
Despite the wide use of CBD, there is little data on its pharmacokinetics, which refers to the activity of drugs in the body over a period of time. Pharmacokinetics studies provide the scientific foundation for claims such as ”fast-acting,” ”long-lasting,” and ”superior bioavailability”. Analysis and understanding of the pharmacokinetic properties of CBD are critical to its use as a therapeutic compound, particularly regarding dosing and routes of administration.
Following the urgency to better understand this issue, Caliper Foods and Colorado State University have completed the CBD industry’s first human clinical study of commercially available CBD-infused food and supplement product pharmacokinetics. The study was published in a special issue of the medical journal Pharmaceuticals in January 2021.
The new study aimed to compare the pharmacokinetics of five different oral CBD preparations over four hours, to examine the relationship between body composition and CBD pharmacokinetics, and to explore the influence of CBD on heart rate variability. So far, only one other study has examined the influence of CBD on heart rate variability in adult humans. Five preparations of CBD, standardized to 30 mg, were orally administered to 15 healthy men and women aged between 21 and 62. Before and 60 min following CBD ingestion, they determined heart rate variability, and body composition was assessed using dual-energy X-ray absorptiometry (measuring bone mineral density using spectral imaging).
As a result, the time to maximum concentration was influenced by body mass index, height, and age. There were no appreciable changes in heart rate and blood pressure in this study.
5% concentration liquid superior
The scientists at Colorado State University used the following preparations in this research: CBD tincture base (MCT oil droplet containing CBD isolate; administered in 227 mL of water), CBD powder in water (CBD as powder, suspended in reverse osmosis water; administered in 227 mL of water), 20% CBD concentration liquid (reverse osmosis water, CBD, MCT oil, quillaja extract; administered in 227 mL of water), 5% CBD concentration powder (water-soluble CBD, sorbitol, modified food starch, natural flavors, MCT; oil administered in 227 mL of water) and 5% CBD concentration liquid (reverse osmosis water, gum arabic, CBD, MCT oil, citric acid; administered in 227 mL of water).
As a result, the scientist concluded that 5% CBD concentration liquid appeared to be superior preparation than most others.
The peak circulating CBD concentration, time to peak concentration, and area under the curve were superior in a preparation comprising 5% CBD concentration liquid. However, 5% CBD concentration liquid had a lower estimate of the total exposure over time compared to 20% CBD concentration liquid.
The explanation for these phenomenal results may not only lay in the fact that this was a concentrated liquid formulation in contrast to tincture or a powder but in the other components in the preparation as well. As scientists pointed out, gum arabic and medium-chain triglycerides (MCTs) have been shown to improve the bioavailability of dietary supplements and may have contributed to this superior performance.
This was an industry ordered but independent study and the findings pointing to the gum arabic as an ingredient that could potentially boost the fast-acting property of the end product is more than inspiring but we will have to wait for more research before we can claim that, f.e. a drug containing CBD and gum arabic can guarantee a fast relief of symptoms.
Nevertheless, this information is worth taking into account as new fast-acting drugs could emerge with new possibilities in treating acute conditions, especially acute pain.