Adhesion of Pressure Sensitive Adhesives with Applications in Transdermal Drug Delivery

2000 ◽  
Vol 662 ◽  
Author(s):  
Marc B. Taub ◽  
Reinhold H. Dauskardt
Keyword(s):  
Drug Delivery ◽  
Stratum Corneum ◽  
Large Scale ◽  
Adhesive Layer ◽  
Strain Energy Release ◽  
Work Of Adhesion ◽  
Adhesive Properties ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Beam Sample

AbstractThe development and implementation of successful transdermal devices for drug delivery requires an understanding of the adhesion occurring between the device and the soft dermal layer. This study utilizes a mechanics approach to quantify the adhesive properties of representative pressure sensitive adhesives (PSAs) used as the adhesive layer in these systems. Debonding of PSAs is accompanied by cavitation in the PSA and the formation of an extensive cohesive zone behind the debond tip. The presence of such large-scale bridging provides significant energy dissipation and increased resistance to delamination. The strain energy release rate (G) during debonding of a cantilever-beam sample, containing at its midline a thin layer of PSA, was utilized to quantify the adhesion of the PSA. The analysis accounts for both the work of adhesion as well as the viscoelastic constitutive behavior of the soft adhesive layer. Effects of strain rate, physiological environment, and permeation-enhancement additions are considered. The resistance of human stratum corneum to debonding between corneocyte layers is also presented, as knowledge of this parameter is essential for developing techniques to test the fracture resistance of the PSA-stratum corneum interface present in the clinical use of these transdermal devices.

Adhesion of Triblock Copolymer-Based Thermoreversible Gels and Pressure Sensitive Adhesives

2000 ◽  
Vol 629 ◽  
Author(s):  
Kenneth R. Shull ◽  
Alfred J. Crosby ◽  
Cynthia M. Flanigan
Keyword(s):  
Elastic Moduli ◽  
Adhesive Layer ◽  
Work Of Adhesion ◽  
Underlying Structure ◽  
Pressure Sensitive Adhesive ◽  
Adhesive Properties ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Surface Development ◽  
Thermoreversible Gels

ABSTRACTTriblock copolymers with poly (methyl methacrylate) (PMMA) end blocks and a poly (n-butyl acrylate) (PnBA) midblock have been synthesized as model pressure sensitive adhesives and thermoreversible gels. These materials dissolve in a variety of alcohols at temperatures above 60 °C to form freely flowing liquids. At lower temperatures the PMMA end-blocks associate so that the solutions form ideally elastic solids. In our case the solvent is 2-ethylhexanol, polymer volume fractions vary from 0.05 to 0.3, and the elastic moduli are close to 10,000 Pa. We have conducted three types of experiments to elucidate the origins of adhesion and bulk mechanical properties of these materials: 1) Weakly adhering gels: The adhesive properties of the gels are dominated by the solvent. Very little adhesion hysteresis is observed in this case, although we do observe hysteresis associated with the frictional response of the layers. 2) Strongly adhering gels. By heating the gels in contact with a PMMA surface, it is possible to bond the gels to the surface. Development of adhesion as the PMMA blocks penetrate into the PMMA substrate can be probed in this case. The cohesive strengths of the gels are found to be substantially greater than their elastic moduli, so that these materials can be reversibly extended to very high strains. These properties have enabled us to probe the origins of elastic shape instabilities that play a very important role in the behavior of thin adhesive layers. 3) Dried gels – model pressure sensitive adhesives. By removing the solvent at low temperatures, the underlying structure of the gel is preserved, giving a thin elastic layer with excellent performance as a pressure sensitive adhesive. Resistance to adhesive failure, expressed as a velocity-dependent fracture energy, greatly exceeds the thermodynamic work of adhesion. This energy is further magnified by ‘bulk’ energy dissipation when the stress applied to the adhesive layer exceeds its yield stress.

Adhesion mechanisms at soft polymer interfaces

2007 ◽  
Vol 366 (1869) ◽  
pp. 1425-1442 ◽  
Author(s):  
Liliane Léger ◽  
Costantino Creton
Keyword(s):  
Adhesive Layer ◽  
Polymer Chains ◽  
Polymer Interfaces ◽  
Adhesive Failure ◽  
Adhesive Properties ◽  
Extraction Mechanism ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Soft Polymer

Based on several significant examples, we analyse the adhesion mechanisms at soft polymer interfaces with a special emphasis first on the role of connector molecules, that is, polymer chains bound to the interface and which transmit stress through a stretching and extraction mechanism, and second on the necessary relay that must be taken by additional dissipation mechanisms acting at larger scales if one wants to reach typical fracture toughnesses in the range of a few 10 J m −2 . Examples of such bulk dissipation mechanisms will be discussed for interfaces between polymer melts and for pressure-sensitive adhesives in contact with a solid surface. We shall particularly point out the fact that the level of adhesion results from a competition between adhesive failure usually driven by both the interactions and the friction properties of the interface and bulk strong deformations which take place in the bulk of the adhesive layer. Controlling the friction properties of the interface then becomes a tool to finely tune adhesive properties.

A TRANSDERMAL DRUG DELIVERY SYSTEM CONTAINING DEFERIOXAMINE MESYLATE FOR THE TREATMENT OF BETA-THALASSAEMIA MAJOR

2011 ◽  
Vol 23 (01) ◽  
pp. 29-35
Author(s):  
Chin-Hsiung Hsieh ◽  
Yuan-An Ku ◽  
Lien-Hua Chiu ◽  
Tai-Horng Young ◽  
Yi-You Huang
Keyword(s):  
Drug Delivery ◽  
Oleic Acid ◽  
Iron Overload ◽  
Drug Delivery System ◽  
Delivery System ◽  
Transdermal Delivery ◽  
Polysorbate 80 ◽  
Thalassaemia Major ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive

Patients with beta-thalassaemia major need blood transfusion frequently during their whole life. However, frequent transfusions will eventually lead to the accumulation of trivalent iron, resulting in iron overload. To reduce iron overload, patients are administered regularly with intravenous or subcutaneous infusion of deferioxamine mesylate (DFO). Nevertheless, high costs of medication, poor patient compliance, and side effects limit its use and patient's acceptance. To overcome such drawbacks, we developed a novel transdermal delivery system to administer the DFO instead of traditional injections. We assayed the feasibility of fabricating a transdermal DFO patch using the single-layer drug-in-adhesive drug delivery system. We used the pressure-sensitive adhesives and hydrogels as the drug reservoirs and studied the release profile of DFO from the transdermal patches in vitro. In order to enhance the transdermal delivery rate, chemical enhancers, polysorbate 80 and oleic acid, and physical enhancer, ultrasound, were incorporated into the monolith DFO patches. Experimental results showed that the combination of polysorbate 80 and oleic acid in the pressure-sensitive adhesives enhanced the penetration efficiency through nude mice skin. The pretreatment of nude mice skin with ultrasound temporally changed the diffusional resistance and facilitated DFO penetration through the skin. We expect that the new delivery system can enable the drug to penetrate through skin at a stable rate and reach the circulation system successfully, thus allowing the concentration of drug to achieve the therapeutic effect.

scholarly journals Robust, universal, and persistent bud secretion adhesion in horse-chestnut trees

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dagmar Voigt ◽  
Jaekang Kim ◽  
Anne Jantschke ◽  
Michael Varenberg
Keyword(s):  
Fatty Acids ◽  
Chemical Properties ◽  
Horse Chestnut ◽  
Adhesive Properties ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Nuclear Magnetic Resonance Spectra ◽  
Component Material ◽  
Dry Out

Abstract Buds of horse-chestnut trees are covered with a viscous fluid, which remains sticky after long-term exposure to heat, frost, radiation, precipitation, deposition of aerosols and particles, attacks by microbes and arthropods. The present study demonstrates that the secretion does not dry out under arid conditions, not melt at 50 °C, and not change significantly under UV radiation or frost at a microscopic level. It is slightly swellable under wet conditions; and, it universally wets and adheres to substrates having different polarities. Measured pull-off forces do not differ between hydrophilic and lipophilic surfaces, ranging between 58 and 186 mN, and resulting in an adhesive strength up to 204 kPa. The mechanical and chemical properties of secretion resemble those of pressure-sensitive adhesives. The Raman, infrared, and nuclear magnetic resonance spectra show the clear presence of saturated aliphatic hydrocarbons, esters, free carboxylic acids, as well as minor amounts of amides and aromatic compounds. We suggest a multi-component material (aliphatic hydrocarbon resin), including alkanes, fatty acids, amides, and tackifying terpenoids embedded in a fluid matrix (fatty acids) comprising nonpolar and polar portions serving the universal and robust adhesive properties. These characteristics matter for ecological-evolutionary aspects and can inspire innovative designs of multifunctional, biomimetic pressure-sensitive adhesives and varnishes.

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