Formulation proteins

Most proteins are not sufficiently stable in aqueous solution to allow formulation as a sterile solution. Instead, the protein is freeze-dried and reconstituted before use. Development of a freeze-dried protein formulation often requires special attention to the details of the freezing process (potential pH shifts and ionic strength increase with freezing) as well as to potential loss of activity with drying. Formulation additives, such as sugars and polyhydroxy compounds, are often useful as cryoprotectants and lyoprotectants. Residual moisture may also be critical to the stability of the dried preparation [33],... 

D. E. Overcashier, T. W. Patapoff, and C. C. Hsu, Lyophilization of protein formulations in vials Investigation of the relationship between resistance to vapor flow during primary drying and small scale product collapse, J. Pharm. Sci., 88(7), 688 (1999). 

Protein Formulation and Delivery, edited by Eugene J. McNally... 

McNally, E. (ed.). 2000. Protein Formulation and Delivery. Marcel Dekker. 

Carpenter, J. 2002. Rational Design of Stable Protein Formulations. Kluwer. 

Cleland, J.L., Powell, M.F., and Shire, S.J. 1993. The development of stable protein formulations a close look at protein aggregation, deamidation and oxidation. Critical Reviews in Therapeutic Drug Carrier Systems 10(4), 3,01-ill. 

High-protein formulations have a nonprotein calorie-nitrogen ratio of less than 125 1. Candidates for these formulations require more than 1.5 g of protein/kg/day and are generally critically ill because of trauma, burns, pressure sores, surgical wounds, or high fistula output. 

Figure 13.4 Perturbation of the melting transition temperature of a single domain protein as a function of benzyl alcohol content (described as % B.A.). The liquid protein formulation consists of 10 mM Tris, 4% mannitol, and 1% sucrose, pH 7.4. (Permission to use the figure granted by BioPharm.)...

Muranishi, S., and Takada, K., Biopharmaceutieal aspeets on enhanced transmembrane delivery of peptides and proteins. In Therapeutic Peptides and Proteins Formulation, Delivery, and Targeting (D. Marshak and D. Liu, eds.), Cold Spring Harbor Laboratory, New York, 1989, pp. 47-50. 

Table 3.6. Exdpients used for protein formulations for inhalation.

Meyer, J.D., J.E. Matsnnra, J.A. Rnth, E. Shelter, S.T. Patel, J. Bansch, E. McGonigle, and M.C. Manning, Selective precipitation of interleukin-4 using hydrophobic ion pairing a method for improved analysis of proteins formulated with large excesses of human serum albumin. Pharm Res, 1994. 11(10) 1492-5. 

Stability of protein formulations investigation of surfactant effects by a novel EPR spectroscopic technique. Pharm Res, 1995. 12(1) 2-11. 

Cleland, IL., M.F Powell, and S.I Shire, The development of stable protein formulations ... 

Figure 13.8. Effects of route and sustained release formulation on the time course of human growth hormone concentration in plasma. Shown is the average time course of human growth hormone (hGH) in plasma after intravenous (0.02mg/kg) and subcutaneous (0.1 mg/kg) administration in humans. Arrows indicate weekly subcutaneous dosing of hGH in solution. A single dose of the same protein formulated in polylactide-co-glycolide (PLG) microspheres (0.75 mg/kg) given subcutaneously sustains human growth hormone levels in plasma for at least one month.

Banga, A.K. (1995). Therapeutic Peptides and Proteins Formulation, Processing and Delivery Systems. Technomic, Lancaster, PA. 

Excipients are additives that are included in a formulation, because they either impart or enhance the stability, delivery, and manufacturability of a drug product. Regardless of the reason for their inclusion, excipients are an integral component of a drug product and therefore need to be safe and well tolerated by patients. For protein drugs, the choice of excipients is particularly important because they can affect both efficacy and immunogenicity of the drug. Hence, protein formulations need to be developed with appropriate selection of excipients that afford suitable stability, safety, and marketability. 

Protein-based drugs have been formulated mainly as stable liquids or in cases where liquid stability is limiting as lyophilized dosage forms to be reconstituted with a suitable diluent prior to injection. This is because their delivery has been limited primarily to the parenteral routes of intravenous (IV), subcutaneous (SC), or intramuscular (IM) administration. There are a few drugs that have been developed for pulmonary delivery, such as rhDNase (Pulmozyme ) and an inhalable formulation of insulin (e.g., Exubra ). However, even such drugs have been formulated as either liquid or lyophilized or spray-dried powders. This chapter will focus only on excipients that are applicable to liquid and lyophilized protein formulations. 

We begin with a brief summary of the degradation pathways of proteins, followed by a discussion on the composition of liquid and lyophilized protein formulations and on various excipients in some detail. An important feature of this chapter is a comprehensive table (Appendix), which details the formulations of approved protein drugs through the year 2005. The table has been compiled with the help of several sources (1,10,11). 

In fact, it is a regulatory expectation that an appropriate excipient be chosen and its level (amount) in a formulation be demonstrated and justified through formulation screening and development studies (29,30). The science of protein formulation development has become increasingly sophisticated over the past 20 years and its discussion is beyond the scope of this chapter. The interested reader is referred to excellent reviews on this subject for further study (31-34). 

While each formulation is unique, there are several general aspects with respect to excipient components in both liquid and lyophilized protein formulations. A comparison of the excipient components in liquid and lyophilized protein formulations is provided in Table 1. 

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