Quality evaluation of commercial lyophilized human growth hormone preparations

The quality of three commercial injections (Genotropin, Humatrope and Norditropin) of lyophilized recombinant human growth hormone (r-hGH) was evaluated in tests by visual inspection, high-performance gel permeation chromatography, polyacrylamide gel electrophoresis, scanning electron microscopy and energy dispersion X-ray microanalysis. The influence of the reconstitution method on gel formation was examined as follows: rapid injection of the diluting solution into a vial against the wall, slow injection onto the surface of the content, and rapid injection onto the surface of the content. The degree of gel formation differed among reconstitution methods. Moreover, fibrous particulate matter in addition to degradation products of r-hGH were evident in all preparations. The quality of r-hGH injection differed among commercial products. Norditropin included the least particulate matter when examined immediately after reconstitution, but it was easily denatured after storage in solution. We advise medical specialists to reconstitute a preparation by the optimal method.