Mannitol stabilizing effect

K. Izutsu, S. Yoshioka, and T. Terao, Effect of mannitol crystallinity on the stabilization of enzymes during freeze drying, Chem. Pharm. Bull. (Tokyo), 42, 5 (1994). 

Purification entails use of an immunoaffinity column containing immobilized murine antifactor VII antibody. It is initially produced as an unactivated, single chain 406 amino acid polypeptide, which is subsequently proteolytically converted into the two-chain active factor Vila complex. After sterilization by filtration, the final product is aseptically filled into its final product containers and freeze-dried. The excipients present in the product include sodium chloride, calcium chloride, polysorbate 80, mannitol and glycylglycine. When freeze-dried in the presence of these stabilizing substances and stored under refrigerated conditions, the product displays a shelf-life of at least 2 years. It has proved effective in the treatment of serious bleeding events in patients displaying anti-factor VIII or IX antibodies. 

Protein drugs have been formulated with excipients intended to stabilize the protein in the milieu of the pharmaceutical product. It has long been known that a variety of low molecular weight compounds have the effect of preserving the activity of proteins and enzymes in solution. These include simple salts, buffer salts and polyhydroxylated compounds such as glycerol, mannitol, sucrose and polyethylene glycols. Certain biocompatible polymers have also been applied for this purpose such as polysaccharides and synthetic polymers such as polyvinyl pyrrolidone and even nonionic surfactants. 

N. Dasovich, T.D. Sweeney, S.J. Shire, C.C. Hsn, and Y.E Maa, Effect of mannitol crystallization on the stability and aerosol performance of a spray-dried pharmaceutical protein, recombinant humanized anti-IgE monoclonal antibody. J Pharm Sci, 1998. 87(11) 1406-11. 

For a two-level factorial design, only two excipients can be selected for each factor. However, for the filler-binder, a combination of brittle and plastic materials is preferred for optimum compaction properties. Therefore, different combinations such as lactose with MCC or mannitol with starch can count as a single factor. Experimental responses can be powder blend flowability, compactibility, blend uniformity, uniformity of dose unit, dissolution, disintegration, and stability under stressed storage conditions. The major advantage of using a DOE to screen prototype formulations is that it allows evaluation of all potential factors simultaneously, systematically, and efficiently. It helps the scientist understand the effect of each formulation factor on each response, as well as potential interaction between factors. It also helps the scientist identify the critical factors based on statistical analysis. DOE results can define a prototype formulation that will meet the predefined requirements for product performance stability and manufacturing. 

Figure 5 Effect of excipients on the storage stability of freeze-dried human growth hormone (hGH). Samples were stored for I month at 40°C. Solid bars, aggregation (primarily dimer). Hatched bars, chemical degradation via methionine oxidation and asparagine deamidation. The glass transition temperatures of the initial freeze-dried formulations are given above the bars when a gla.ss transition temperature could be measured by DSC. The glycine mannitol formulation is a weight ratio of hGH glycine mannitol of 1 1 5, the dex-tran formulation is 1 6 hGH dextran 40, none means no stabilizer, and the others are 1 1 hGH stabilizer. All formulations contain sodium phosphate buffer (pH 7.4) at 15% of the hGH content. Initial moisture contents are all ==1%. (Data from [4].)...

---