Quantitative analysis of chondroitin sulfate in raw materials, ophthalmic solutions, soft capsules and liquid preparations

We performed the quantitative analysis of chondroitin sulfate (CS) obtained from raw materials and various pharmaceutical preparations. To quantify CS content in raw materials and in an ophthalmic solution, each test sample and the authentic CS were first digested by chondroitinase ABC. The CS disaccharides produced were analyzed by strong anion-exchange high-performance liquid chromatography (SAX-HPLC) and CS content was quantified by calculating the total peak areas of the disaccharides derived from a CS calibration curve. In the case of soft capsules, CS was first extracted with hexane followed by phenol–chloroform to remove oil and protein ingredients. The extracted CS samples were depolymerized by chondroitinase ABC and CS content was determined. Quantitative analysis of the disaccharides derived from raw materials and an ophthalmic solution showed the CS contents (%) were 39.5 ± 0.1 to 105.6 ± 0.1 and 103.3 ± 1.2, respectively. In case of CS analysis in soft capsules and liquid preparations, the overall recovery (%) of the spiked CS was 96.79 ± 0.53–103.54 ± 1.78 and 97.10 ± 1.82 to 103.17 ± 2.34, respectively. In conclusion, the quantitative analysis of the disaccharides produced by enzymatic digestion can be used in the direct quantitation of CS containing pharmaceutical formulations.