Phenylephrine Colon-Targeted Erodible Layer Formulation
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Solution Overview
Problem
Current phenylephrine formulations require frequent administration due to their short half-life, leading to sub-optimal efficacy and increased side effects from peak plasma levels, and they undergo extensive pre-systemic modification in the upper gastrointestinal tract, reducing bioavailability.
Innovation Solution
Development of oral pharmaceutical compositions that allow phenylephrine to be absorbed from the colon, using erodible layers and colon-specific substrates to sustain plasma concentrations, with formulations designed for single-dose administration every 8, 12, or 24 hours, maintaining therapeutic levels and minimizing pre-systemic modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phenylephrine is administered using conventional immediate release formulations, then rapid absorption occurs, but frequent dosing (every 4 hours) is required due to short half-life
Solution Approach 1:
The patent segments the gastrointestinal tract into upper GI tract and colon, using site-specific drug release to achieve different absorption kinetics. By dividing the delivery system into immediate release (upper GI) and sustained release (colon) components, the invention resolves the contradiction between rapid absorption and prolonged duration of action.
Solution Approach 2:
The patent introduces an intermediary mechanism (colon-targeted delivery system using pH-sensitive or enzyme-sensitive polymers) that mediates between the drug and the absorption site. This intermediary enables controlled release in the colon, extending the duration of therapeutic effect while maintaining initial rapid absorption from upper GI tract.
2Reliability
If phenylephrine is administered frequently to maintain therapeutic levels, then sustained efficacy is achieved, but patient compliance decreases and side effects increase
Solution Approach 1:
The patent achieves continuity of useful action by ensuring phenylephrine is continuously absorbed from the colon over an extended period (12-24 hours). This continuous release from the colon maintains stable plasma concentrations, improving therapeutic efficacy while allowing less frequent dosing, thereby enhancing patient compliance.
Solution Approach 2:
The patent changes the release rate parameter of phenylephrine by using different polymer matrices with varying degradation rates. This parameter change enables the drug to be released slowly over 12-24 hours from the colon, maintaining reliable therapeutic levels while reducing dosing frequency and improving compliance.
3Speed
If phenylephrine is absorbed from the upper gastrointestinal tract, then rapid onset occurs, but extensive pre-systemic modification reduces bioavailability
Solution Approach 1:
The patent segments the absorption process into two phases: rapid absorption from upper GI tract (providing quick onset) and sustained absorption from colon (providing high bioavailability). This segmentation allows the drug to benefit from both rapid onset and extended availability, resolving the contradiction between speed and quantity.
Solution Approach 2:
The patent employs preliminary action by using pH-sensitive or enzyme-sensitive polymer coatings that protect phenylephrine during transit through the upper GI tract. These coatings dissolve or degrade at specific pH levels or in response to colon-specific enzymes, releasing the drug in the colon where pre-systemic modification is minimal, thus preserving bioavailability.
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
The approach provides sustained bioavailability and improved patient compliance by maintaining effective plasma levels of unconjugated phenylephrine for extended periods, reducing side effects and enhancing therapeutic efficacy.
Implementation Method 1
the erodible layer comprises colon-specific substrates and erodes in the colon... the colon-specific substrate erodes in the presence of colon-specific enzymes
Implementation Method 2
phenylephrine is efficiently absorbed from the colon... formulations which permit absorption from the colon will provide a larger proportion of phenylephrine remaining in a therapeutically active unconjugated form
Data Source
AI summary
The invention discloses a pharmaceutical composition comprising phenylephrine or a pharmaceutically acceptable salt thereof and an erodible layer which is for oral administration wherein the composition delivers phenylephrine or a pharmaceutically acceptable salt thereof via absorption in the colon. The pharmaceutical composition comprises a core comprising phenylephrine or a pharmaceutically acceptable salt thereof and an erodible layer which is in a time-dependent, pH-dependent, or colon-specific enzyme-dependent erodible layer that degrades to expose the core to release phenylephrine in the colon. In one preferred embodiment, the erodible layer encases the core. The composition optionally further comprises phenylephrine in the erodible layer or other additional layer(s). The pharmaceutical composition can further comprise one or more additional therapeutically active agents selected from one or more of the group consisting of antihistamines, analgesics, anti-pyretics, and non-steroidal anti-inflammatory agents. The invention also discloses methods of administering phenylephrine via the colon, thereby increasing the bioavailable amount of therapeutically active unconjugated phenylephrine relative to the total phenylephrine in the plasma.