Medicated patches for the relief of varicose vein symptoms
A biodegradable composite patch with a chitosan-alginate hydrogel and PLA microfiber layer addresses the inefficiencies of existing treatments by providing controlled topical release of vasodilators for varicose veins, enhancing symptom relief through localized delivery and reducing systemic exposure.
Patent Information
- Application Number
- DE202025107220
- Authority / Receiving Office
- DE · DE
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-01-15
- Estimated Expiration
- 2035-11-30
AI Technical Summary
Existing treatments for varicose veins and chronic venous insufficiency often result in systemic exposure of medications and lack effective localized control of vasodilator release, leading to inefficiencies in symptom relief.
A biodegradable composite bio-scaffold patch composed of a chitosan-alginate hydrogel layer and a PLA microfiber layer, encapsulating amlodipine, nifedipine, or prazosin, provides controlled topical release of active ingredients for varicose veins, utilizing ionic cross-linking and lamination to regulate drug delivery.
The patch achieves localized and sustained release of vasodilators, reducing systemic absorption and enhancing therapeutic efficacy for varicose vein symptoms while maintaining biocompatibility and mechanical stability.
Abstract
Description
Application area of the invention
[0001] The invention relates to bio-based drug patches made of biodegradable polymers such as chitosan, alginate, and polylactic acid for the controlled topical release of vasodilators to alleviate varicose vein symptoms. Chitosan-alginate scaffolds are widely used in tissue engineering and drug delivery systems due to their biocompatibility, porosity, and the possibility of regulated drug release. Background of the invention
[0002] Varicose veins and chronic venous insufficiency are associated with venous hypertension, inflammation, and pain, which are often treated with compression and medication. Topical delivery systems can concentrate active ingredients locally while limiting systemic exposure. Biopolymer scaffolds made of chitosan and alginate are characterized by high porosity, water absorption, and biocompatibility and are used for wound healing and controlled drug release; PLA provides mechanical stability and biodegradability. Ionic cross-linked chitosan-alginate networks and composite laminae can encapsulate low-molecular-weight drugs and modulate their release via polymer ratios, cross-linking density, and porosity. These properties make a composite scaffold patch with embedded calcium channel blockers or alpha blockers an attractive option for local vascular modulatory effects with sustained release. Summary of the invention
[0003] The invention relates to a biodegradable composite bio-scaffold patch consisting of a physically or ionically cross-linked chitosan alginate hydrogel layer and a reinforcing PLA microfiber or cast film layer. The scaffold encapsulates an active ingredient selected from amlodipine, nifedipine, or prazosin. The scaffold is intended for topical application to superficial varicose veins and enables controlled release over hours to days.
[0004] The specification further discloses a manufacturing process that includes casting from a solution and freeze-drying chitosan alginate with drug incorporation, ionic crosslinking to adjust porosity, and lamination with a PLA layer to improve handling and regulate diffusion. Although the manufacturing process is described, the claims relate to the scaffold article and its structural and release properties. Detailed description
[0005] A chitosan solution is prepared by dissolving medium-molecular-weight chitosan in dilute acetic acid; an alginate solution is prepared in deionized water. The active ingredient (amlodipine, nifedipine, or prazosin) is dissolved or dispersed in a suitable solvent system compatible with the polymer phase, optionally using cosolvents or complexing agents to improve solubility. The solutions are mixed with stirring to obtain a homogeneous mixture; the mixture is poured into molds and subjected to controlled freezing and lyophilization to generate a porous framework. Ionic crosslinking is achieved by exposure to a calcium chloride mist or bath to form alginate-calcium bridges, followed by neutralization and washing to remove residues.
[0006] A PLA carrier layer is formed into a microfiber mat by casting or electrospinning. This PLA layer is laminated to the chitosan-alginate scaffold using a mild solvent-based adhesive or biocompatible adhesive. This creates a two-layer patch with a skin-contacting hydrogel side and an outer barrier / reinforcement side. Porosity (>90% in typical chitosan-alginate scaffolds) and pore size are controlled by the polymer ratio, freezing rate, and crosslinker concentration, thus allowing for precise adjustment of the release kinetics.
[0007] Optional excipients include plasticizers (glycerin), stabilizers, and permeability modifiers (e.g., PVA) to adjust mechanical flexibility and drug diffusion. Surface coatings (e.g., chitosan quaternary derivatives) can improve antimicrobial properties and adhesion. The patch can be cut to size and packaged sterile.
[0008] The drug loading targets therapeutic concentrations compatible with topical vasomodulation while limiting systemic absorption. Release profiles are characterized in vitro using Franz diffusion cells, and mechanical properties are assessed by tensile tests. FT-IR confirms polymer interactions; SEM evaluates pore morphology; swelling and erosion studies serve as the basis for release modeling.
[0009] During application, the patch is applied to the skin over the varicose veins; moisture activates the hydrogel, and the active ingredient diffuses through the skin with controlled kinetics, which are influenced by the porosity of the backing material and the barrier properties of the PLA. The backing material degrades over time, and the patches are replaced after each treatment cycle.
Claims
[1] A biodegradable bio-scaffold patch for topical application, comprising a porous chitosan alginate layer and a poly(lactic acid) carrier layer, wherein the porous layer encapsulates an active ingredient selected from amlodipine, nifedipine or prazosin and the patch is configured to allow controlled release onto the skin over varicose veins. [2] Plaster according to claim 1, wherein the chitosan alginate layer is ionically cross-linked with calcium ions and has a porosity of more than 80%, wherein the pore size and cross-linking density are selected such that the drug release is modulated over at least 8-72 hours. [3] Plaster according to claim 1, wherein the poly(lactic acid) layer is a microfiber mat or a cast film laminated onto the porous layer to provide mechanical reinforcement and directed diffusion, wherein the PLA layer faces outwards during use. [4] Plaster according to claim 1, further comprising excipients selected from plasticizers, stabilizers and permeability modifiers to adjust flexibility, stability and drug flow, and an antimicrobial surface coating for skin contact on the porous layer.