Different analyses measure chondroitin pharmacokinetics

More chondroitin sulfate of bovine origin is absorbed than that of shark origin in several studies.

Issue: May 2006

ByNicola Volpi, BSc, Biol

Nicola Volpi, BSc, Biol [photo]
Nicola Volpi

Chondroitin sulfate is a heterogeneous polysaccharide in terms of structure, molecular mass, and biological and pharmacological properties. The structure and properties of polysaccharides strongly influence their absorption and bioavailability by oral route.

Chondroitin sulfate derives from various sources such as fish, pig, bovine, avian and shark cartilage. Each source is different in terms of molecular mass and dispersity. Furthermore, purity of the cartilage samples may change greatly during the extraction process and influence pharmacological activities.

Measuring pharmacokinetics

Measuring the pharmacokinetic parameters of orally administered chondroitin sulfate is driven by specific and related analytical procedures. Various analytic techniques exist to quantify and qualify endogenous chondroitin sulfate in small volumes of human plasma, ranging from 100 µL to 500 µL.

The first technique involves agarose-gel electrophoresis separation of increasing amounts of chondroitin sulfate, with a detection limit of about 200 ng, using sequential staining with toluidine blue followed by Stains-All procedure.¹ After extraction from 200 µL to 400 µL human plasma, chondroitin sulfate is quantified by means of agarose-gel electrophoresis and specific calibration curves (Figures 1A and B).

Figure 1. Agarose-gel electrophoresis (A) and calibration curves (B) quantify chondroitin sulfate pharmacokinetics.

Source: Volpi N.

High-performance liquid chromatography (HPLC) separation of chondroitin sulfate disaccharides with postcolumn derivatization and 2-cyanoacetamide and fluorometric detection is also a sensitive method to measure human plasma chondroitin sulfate disaccharides.²

This approach permits the quantitative separation of chondroitin sulfate after its extraction from human plasma with a detection limit of about 200 ng and a range of 200 ng to 1000 ng.

Another sensitive technique to measure chondroitin sulfate in human plasma is fluorophore-assisted carbohydrate electrophoresis analysis of human plasma chondroitin sulfate disaccharides.² Unsaturated disaccharides are flurotargeted and separated following extraction from human plasma and treatment with a nonspecific protease. The resulting calibration curve is linear from 100 ng to 1000 ng (Figures 2A and B).

Combining methods

I helped administer research involving 20 healthy Caucasian men, aged 18 to 30 years, who participated in two studies of oral absorption of 4 g of chondroitin sulfate from bovine or fish cartilage.^3,4

Figure 2. Fluorophore-assisted carbohydrate electrophoresis (A) analyzes human plasma chondroitin sulfate disaccharides producing a linear calibration curve (B) from 100 ng to 1000 ng.

Source: Volpi N.

Using agarose-gel electrophoresis and HPLC, we measured qualitative and quantitative variations in normal human plasma after oral administration of chondroitin sulfate derived from bovine and fish cartilage. Plasma levels of endogenous chondroitin sulfate were detectable in all volunteers.

The mean values calculated for six men varied during the day from 0.3 µg/mL to 5.3 µg/mL. After administration of bovine chondroitin sulfate, plasma levels increased more than 200% in all volunteers with a peak concentration after two hours. Plasma level increase reached significance from two hours to six hours.

Absorption

The mean plasma curve of exogenous chondroitin sulfate of bovine origin peaks between 2.4 hours and five hours after oral absorption, according to several studies.^3,5,6

Chondroitin sulfate from shark cartilage peaks at 8.7 hours.⁴ The oral absorption of partially depolymerized shark chondroitin sulfate maxes at four hours.⁷

The structure and properties of polysaccharides strongly influence their absorption and bioavailability by oral route, according to these studies.

The extent of absorption depends on the type of oral chondroitin sulfate.^3,4 Following oral administration of 4 g of bovine chondroitin sulfate, 5% of the drug is absorbed.

Following administration of 4 g of shark chondroitin sulfate, about 2.5% is absorbed. Using different analytical procedures, other authors found a bioavailability of 15% to 24% in humans and 22% to 32% in horses.^5-8

Absorption of exogenous chondroitin sulfate changed the composition of plasma chondroitin sulfate. Following drug administration, a decrease of nonsulfated disaccharide and appearance of 6-sulfated disaccharide became evident.

The mean sulfate-to-disaccharide ratio also increased after chondroitin sulfate administration, confirming the presence of a more sulfated chondroitin sulfate than endogenous chondroitin sulfate. Researches have also observed these effects in animals.⁸

References

Volpi N, Maccari F. Detection of submicrogram quantities of glycosaminoglycans on agarose-gels by sequential staining with toludine blue and Stains-All. Electrophoresis. 2002;23:4060-4066.
Volpi N, Maccari F. Microdetermination of chondroitin sulfate in normal human plasma by fluorophore-assisted carbohydrate electrophoresis (FACE). Clin Chim Acta. 2005;356:125-133.
Volpi N. Oral bioavailability of chondroitin sulfate (Condrosulf) and its constituents in healthy male volunteers. Osteoarthritis Cartilage. 2002;10:768-777.
Volpi N. Oral absorption and bioavailability of ichthyic origin chondroitin sulfate in healthy male volunteers. Osteoarthritis Cartilage. 2003;11:433-441.
Conte A, De Bernardi M, Palmieri L, et al. Metabolic fate of exogenous chondroitin sulfate in man. Arzneim-Forsch/Drug Res. 1991;41:768-772.
Conte A, Volpi N, Palmieri L, et al. Biochemical and pharmacokinetic aspects of oral treatment with chondroitin sulfate. Arzneim-Forsch/Drug Res. 1995;45;918-925.
Ronca G, Conte A. Metabolic fate of partially depolymerized shark chondroitin sulfate in man. Int J Clin Pharmacol Res. 1993;13 Suppl:27-34.
Du J, White N, Eddington ND. The bioavailability and pharmacokinetics of glucosamine hydrochloride and chondroitin sulfate after oral and intravenous single dose administration in the horse. Biopharm Drug Dispos. 2004;25:109-116.