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Phospholipid polymer, 2-methacryloyloxyethyl phosphorylcholine and its skin barrier function
1College of Pharmacy, Duksung Women's University Ssangmun-dong, Dobong-ku, Seoul 132-714, Korea. aeri@duksung.ac.kr
Archives of Pharmacal Research
|December 15, 2004
Summary
Poly[2-methacryloyloxyethyl phosphorylcholine] (pMPC) protects skin barrier function by preventing stratum corneum disruption during drug permeation studies. This polymer reduces nicotinic acid (NA) permeation, maintaining skin integrity against hydration effects.
Area of Science:
- Biomaterials Science
- Dermal Drug Delivery
- Surface Chemistry
Background:
- The stratum corneum (SC) is the primary barrier to transdermal drug delivery.
- Understanding how substances affect skin barrier integrity is crucial for developing effective topical formulations.
- Extensive hydration can disrupt the SC's inter-lamellar bilayer (ILB) structure, compromising barrier function.
Purpose of the Study:
- To investigate the effect of poly[2-methacryloyloxyethyl phosphorylcholine] (pMPC) on skin permeation properties.
- To evaluate the influence of pMPC on the skin barrier function during in vitro permeation of nicotinic acid (NA).
- To elucidate the structural changes in the SC, ILB, and dermis induced by pMPC and hydration.
Main Methods:
- In vitro skin permeation studies using side-by-side diffusion cells with nicotinic acid (NA) as a model drug.
- Evaluation of NA permeation rates in the presence and absence of pMPC in the donor solution.
- Transmission electron microscopy (TEM) to analyze structural alterations in skin layers (SC, ILB, dermis).
Main Results:
- Nicotinic acid permeation without pMPC showed a biphasic profile with a significant 10-fold increase in flux during the hydration phase, indicating barrier disruption.
- In the presence of 3% pMPC, NA permeation followed a monophasic pattern with a reduced steady-state flux (10.9 microg/cm2/h), demonstrating a concentration-dependent decrease in permeation.
- TEM analysis revealed that pMPC-treated skin maintained cohesive corneocytes and tight epidermal-dermal junctions, unlike water-treated skin which showed intercellular separation.
Conclusions:
- Poly[2-methacryloyloxyethyl phosphorylcholine] (pMPC) significantly reduces the permeation of nicotinic acid across the skin.
- pMPC protects the skin's barrier function by preventing the disruption of the inter-lamellar bilayer structure caused by extensive hydration.
- These findings suggest pMPC is a promising excipient for enhancing dermal drug delivery while preserving skin integrity.