The aim of this thesis was to develop drug encapsulation in chitosan nanoparticles for der- mal patch formulations. The thesis project included the optimization of preparation protocols of drug capsulated nanoparticles by using a model drug and a variety of synthetic routes. Subsequently, the model drug was replaced by the local anesthetic drug, lidocaine. In addi- tion, one part of the project was to develop a thin polymer film which incorporates lidocaine- encapsulated chitosan nanoparticles. Ph.D. Didem Sen Karaman from Åbo Akademi Uni- versity acted as a supervisor and an expert during this thesis project. The thesis was com- missioned by the Pharmaceutical Sciences Laboratory at Åbo Akademi University.

Nanotechnology refers to technology that utilizes nanosized materials with a diameter of 1- 100 nanometers of materials. Nanoparticles have specific properties, based on their large surface area / mass ratio and specific physicochemical properties. When the material is processed to nanoscale, the chemical, physical and biological properties are either signifi- cantly better or completely different as compared to conventional materials.

Chitosan is a natural biopolymer which can be used in drug delivery due to its many good properties. For example, it is non-toxic, biodegradable and has bactericidal and growth-in- hibiting effects. Lidocaine is a widely used drug for local anesthesia. Its effect is based on the fact that it is nonionic, which means it can easily pass through the cell membrane. Lido- caine has the ability to close sodium channels of nerve cells and thus prevent the transmis- sion of nerve impulses.

Thin polymer films are being developed for use in drug delivery. They have a number of advantages, including the possibility of designing different drug dosing on the natural poly- mer matrix. In addition, a thin polymer film which incorporates drug-encapsulated nanopar- ticles modify the release rate of the drug, reduce toxicity and enhance the therapeutic effi- ciency.

The obtained results revealed that encapsulation of lidocaine into chitosan nanoparticles improves the release of drug compared to free lidocaine in the patch formulation. In addition, the flux of drug from the film is higher when the formulation contains nanoparticles. However, the results showed that the nanoparticles’ incorporation route in the patches must be im- proved.