Previous studies have established that the selective precipitation of a less soluble buffer component during freezing can induce a significant pH shift in the freeze concentrate. During freezing of sodium phosphate solutions, crystallization of the disodium salt can produce a pH decrease as great as 3 pH units which can dramatically affect protein stability. The objective of our study was to determine how the presence of glycine (0-500 mM), a commonly used bulking agent in pharmaceutical protein formulations, affects the pH changes normally observed during freezing in sodium phosphate buffer solutions and to determine whether these pH changes contribute to instability of model proteins in glycine/phosphate formulations. During freezing in sodium phosphate buffers, the presence of glycine significantly influenced the pH. Glycine at the lower concentrations (< or = 50 mM) suppressed the pH decrease normally observed during freezing in 10 and 100 mM sodium phosphate buffer, possibly by reducing the nucleation rate of salt and thereby decreasing the extent of buffer salt crystallization. The presence of glycine at higher concentration (> 100 mM) in the sodium phosphate buffer resulted in a more complete crystallization of the disodium salt as indicated by the frozen pH values closer to the equilibrium value (pH ). Although high concentrations of glycine can facilitate more buffer salt crystallization and these pH shifts may prove to be potentially damaging to the protein, glycine, in its amorphous state, can also act to stabilize a protein via the preferential exclusion mechanism.
Artificial colors - Current accepted colors for food use are Blue No. 1 (E133, Triarylmethane dye, disodium salt), Blue No. 2 (Indigo carmine, E132), Yellow No. 5 (Tartrazine, E102), Yellow No. 6 (E110, banned or restricted as a food additive in Norway, Finland and Sweden), Red No. 3 (Erythrosine), and Red No. 40 (Allura Red AC, banned in many European countries). High consumption of Allura Red has claimed an adverse effects of human health including allergies, food intolerance, cancer, multiple sclerosis, attention deficit hyperactivity disorder, brain damage, nausea, cardiac disease and asthma. 2
In general, preferred compositions of the present invention contain up to about 5% by weight of a corticosteriod, up to about 60% by weight drying agent, one or more optional ingredients (for example, one or more anti-itch agents; anti-foaming agents; buffers, neutralizing agents, and agents to adjust pH; coloring agents and decoloring agents; emollients; emulsifying agents, emulsion stabilizers and viscosity builders; humectants; odorants; preservatives, antioxidants, and chemical stabilizers; solvents; and thickening, stiffening, and suspending agents), and a balance of water or solvent.