Protein pharmaceutically active

M. Mumenthaler, C. C. Hsu, and R. Pearlman, Feasibility study on spray-drying protein pharmaceuticals recombinant human growth hormone and tissue-type plasminogen activator, Pharm. Res, 11(1), 12 (1994). 

Enzymes are useful catalysts for a broad diversity of chemical reactions that enable the synthesis of natural and unnatural highly pure pharmaceutically active compounds. However, proteins themselves can also be the pharmaceutical ingredients. 

Although, these capabilities can be directed to multiple products to target different markets (chemicals, agriculture, protein pharmaceuticals, and prophylactic and therapeutic vaccines) their activities are currently focused to the Health Sector. Within these markets, they are focused on specific high-value opportunities. 

The significance of protein oxidation became paramount with the advent of recombinant protein biologies used as human therapeutics. Careful characterization of protein stability is essential to maintaining the efficacy of protein pharmaceuticals. If even a single side chain amino acid residue becomes oxidized, then a protein therapeutic may not have the same activity in vivo as the unmodified protein. 

Figure 5.10. Possible mechanisms of chemical and physical instability that influence biological activities of protein pharmaceuticals. (Adapted from Manning et al. [18])...

To achieve a reasonable degree of absorption, peptide and protein pharmaceuticals may need permeation enhancers to promote passage across mucosal cells. Another concern is that studies of insulin and enkephalin in animals suggest that protease activity may be high, especially in the rectal cavity [5,6]. On the other hand, the density of lymphatic vessels and drainage therein at these sites may be advantageous compared with other routes of administration. 

Some saponins from plants are quite phytotoxic,36 but little is known of their mode(s) of action. Some of these compounds have effects on membrane properties, due to their detergent-like activity. However, all membrane effects are apparently not due to nonspecific effects on membrane lipids. Kauss and Jeblick23 provided indirect evidence that digitonin effects on plant cell Ca2+ uptake are due to effects on membrane protein phosphorylation/dephosphorylation processes. Betulin (Fig. 10.1), a phytotoxic saponin,22 is known for its pharmaceutical activity. It is an inhibitor of DNA topoisomerase.45 The natural product-based DNA topoisomerase inhibitor drug podophyllotoxin is also phytotoxic.37... 

Multiple weak interactions allow small pharmaceutically active molecules to be trapped in polymeric dendrimers. Over time the molecules slowly break free and are released in a controlled manner to the sites where they are required. The formation of dendrimer prodrugs allows for covalent attachment of many copies of a drug to a single dendrimer. Under predetermined conditions, such as pH or oxygen content, the bonds break and the drug is released in a concentrated burst. Weak interactions can also be harmful. The entanglement of small amyloid proteins appears to be responsible for the formation of plaques associated with Alzheimer s disease. The presence of transition metals poses an added complication as they have been implicated in protein crosslinking. A multifunctional molecule that can both disrupt... 

Solubility, enzyme activity, chemical and conformational stability of pharmaceutically active proteins under non-aqueous conditions have been well characterized (Zaks and Klibanov, 1988a Zaks and Klibanov 1988b Houen, 1996). Many of the solvents utilized in the literature are not pharmaceutically acceptable, and much of this work has not been directly applied to non-aqueous pharmaceutical formulations. However, the fundamental science and elucidation of concepts important to successfully utilizing non-aqueous conditions are applicable from this literature base. Furthermore, prediction of activity, solubility, chemical and structural stability are not routine, and preformulation work must be done on a targeted basis. 

Mumenthaler M, Hsu CC, and Pearlman R. Feasibility study on Spray-drying Protein Pharmaceuticals Recombinant Human Growth Hormone and Tissue-type Plasminogen Activator. Pharm Res 1994 11(1) 12—20. 

Note that analytical activities for protein pharmaceutical products follow similar principles but use methods for in vitro or in vivo (animal model) bioactivity, electrophoretic and chromatographic methods, amino acid analysis, peptide mapping, sequencing, etc., for characterization. 

Pharmaceutical companies are increasingly interested in developing products based on proteins, enzymes, and peptides. With the development of such products comes the need for methods to evaluate the purity and structural nature of these biopharmaceuticals. Proteins, unlike traditional pharmaceutical entities, rely on a specific secondary structure for efficacy. Methods to monitor the secondary structure of pharmaceutically active proteins, thus, is necessary. Infrared spectroscopy provides a way to study these compounds quickly and easily. Byler et al. (65) used second-derivative IR to assess the purity and structural integrity of porcine pancreatic elastase. Seven different lyophilized samples of porcine pancreatic elastase were dissolved in D20, placed in demountable cells with CaF2 windows, and IR spectra obtained. The second derivatives of the spectra were calculated and the spectral features due to residual water vapor and D20 removed. 

---