Preformulation studies and characterization of proposed chondroprotective agents: glucosamine HCl and chondroitin...

Glucosamine HCl and chondroitin sulfate are proposed chondroprotective agents commonly used as dietary supplements. This study examined the physicochemical and mechanical properties of chondroitin sulfate, glucosamine HCl powder, and glucosamine HCl granulation obtained from various sources.

The particle size distributions of the materials were determined using sieve analysis and time-of-flight techniques. Polarized light microscopy was used to examine particle morphology. Powder x-ray diffraction studies, moisture sorption isotherms, deformation behavior, powder flow, and compaction characteristics were also investigated. The polarized light microscopy and x-ray diffraction patterns showed that chondroitin sulfate is amorphous while glucosamine HCl is crystalline. Particle sizes of chondroitin sulfate and glucosamine HCl varied widely, depending on their source or manufacturing technique (e.g., granulation). The studied samples of shark-derived chondroitin sulfate had a small median particle size (4 microns) compared to that derived from bovine cartilage (17 microns). Different moisture sorption profiles were obtained for the glucosamine HCl granulations studied. Glucosamine HCl granulation from Supplier I showed no observable moisture sorption, while the granulation from Supplier II showed an approximately 5% weight gain. Conversely, chondroitin sulfate was extremely hygroscopic and deliquescent. The Carr's indices for glucosamine HCl samples ranged from 12.5 to 31.5; for chondroitin sulfate the values were 25.2 and 53.6. The compression analysis showed that all chondroitin sulfate samples exhibited plastic deformation behavior, with the shark-derived chondroitin sulfate forming superior compacts when compared to the bovine. The dominant mechanism of compression of glucosamine HCl powder was brittle fracture, whereas wet granulated glucosamine HCl exhibited plastic deformation with enhanced mechanical strength.

The physicochemical and mechanical characteristics between the various dietary supplements studied varied greatly. Data obtained from this study provide an understanding of the physicomechanical behavior of chondroitin sulfate and glucosamine HCl. Application of this knowledge would facilitate development of stable solid dosage forms containing these materials.