C-CPE Fragment Enhances Peptide Drug Mucosal Absorption
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Solution Overview
Problem
Peptide drugs with high molecular weights are poorly absorbed through mucosal tissues due to their size and susceptibility to protease digestion, limiting their administration routes to invasive injections, and existing absorption-enhancing agents are toxic and unsuitable for long-term use.
Innovation Solution
The use of a C-terminal fragment (C-CPE) of the enterotoxin produced by Clostridium perfringens, or its mutants with deleted amino acid residues, to enhance mucosal absorption of peptide drugs by increasing the permeability of tight junctions without causing tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional absorption-enhancing agents (fatty acids, bile acid, chelating agents) are used to improve mucosal permeation of peptide drugs, then absorption enhancement is achieved, but strong toxicity against mucosal epithelial cells occurs making them unsuitable for long-term administration
Solution Approach 1:
The patent uses claudin-4 as an intermediary target - a naturally occurring tight junction protein that mediates paracellular transport. By designing C-CPE to specifically bind and modulate claudin-4 function, the invention achieves absorption enhancement through a physiological pathway rather than causing direct membrane disruption, thereby avoiding the cytotoxicity of conventional agents while maintaining permeation enhancement capability
Solution Approach 2:
The invention changes the mechanism parameter from direct membrane disruption (physical/chemical damage) to specific protein-protein interaction (biological modulation). C-CPE binds to claudin-4 and modulates its conformation or function to increase paracellular permeability, representing a fundamental parameter change from destructive to constructive absorption enhancement that eliminates toxicity
2Ease of operation
If peptide drugs are administered orally or via other mucosal routes, then non-invasive administration is achieved, but absorption is poor due to high molecular weight and protease digestion
Solution Approach 1:
The patent applies preliminary action by pre-treating the mucosal barrier with C-CPE to open tight junctions before peptide drug administration. This preliminary modification of the absorption barrier creates a permissive environment that enables subsequent peptide drug permeation, addressing the absorption problem without requiring changes to the peptide structure or administration technique
Solution Approach 2:
Claudin-4 serves as an intermediary that mediates between the absorption-enhancing agent and the peptide drug. C-CPE binds to claudin-4 to modulate tight junction permeability, creating a transient pathway that allows peptide drugs to pass through the epithelium via paracellular transport, thereby enabling oral and other mucosal routes for peptides that would otherwise be poorly absorbed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly improves the bioavailability of peptide drugs like hPTH(1-34) and human ghrelin through non-invasive mucosal routes, such as intestinal, nasal, and pulmonary administration, with enhanced absorption and reduced toxicity compared to conventional absorption-enhancing agents.
Implementation Method 1
enhance the permeability of tight junctions without causing tissue damage
Data Source
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AI summary
A mucosal absorption-enhancing agent is provided that enables oral, nasal or pulmonary administration of peptide drugs whose administration route has heretofore been limited to the injections due to their poor absorption from the mucosa. Specifically, the mucosal absorption of peptide drugs via intestinal, pulmonary or nasal route can be enhanced by allowing the peptide drugs with the C-terminal fragment (C-CPE) of an enterotoxin (CPE) produced by the bacterium Clostridium perfringens of the genus Clostridium, in particular with the C-CPE or its mutants resulting from the substitution and/or deletion of one or several amino acid residues of the C-CPE to act thereon. The composition for mucosal administration of the present invention significantly enhances absorption of peptide drugs, such as human parathyroid hormone hPTH(1-34), human ghrelin and human motilin, through the mucosa of small intestine, lung, nasal cavity and other mucosa. Also, unlike any of the conventional mucosal absorption-enhancers, the composition for mucosal administration of the present invention does not cause tissue damage and is therefore highly safe for use.