Some mechanical property considerations of reconstituted collagen for drug release supports

Reconstituted collagen, having been shown previously to be biodegradable and to have low immunologic activity, has been further evaluated here as a vehicle for drug delivery. Mechanical stress-strain (Young's Modulus), mechanical abrasion resistance, and steroid (medroxyprogesterone) diffusion rates have been determined for collagen films subjected to nine different chemical preparative treatments. The treatments fall into three categories: formaldehyde crosslinking, chrome tanning, and a combination of formaldehyde and chrome. Based on our conditions, the formaldehyde films have been found to have higher Young's Moduli and lower diffusion release rates of medroxyprogesterone acetate (MPA) than the untreated films. The largest chrome complexes apparently open up the collagen matrix to yield higher diffusion release rates than the untreated film. The Young's Modulus is 2--3 times higher for the chrome films that the untreated film but the abrasion resistance is generally substantially less. Combination chrome/formaldehyde treatments yield film properties between those of the two separate treatments.