Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
NEW CARBON MATERIALS - APPLICATION IN CUMULATION AND DELIVERY OF ORGANIC COMPOUNDS (INCLUDING DRUGS) SUMMARY The primary objective of this study was to determine the effect of porous structure and chemical nature of carbon materials surface in the process of phenol and paracetamol adsorption and desorption from aqueous solutions. Additionally, some possibilities of carbon materials application as potential carriers of paracetamol in the systems of controlled drug release was studied. Two groups of adsorbents were used. The first group included carbon materials CP3 obtained from sucrose. The second group consisted of two series of carbon nanotubes labeled as A and H. The characteristics of applied carbon materials were based on the following methods: sorption analysis, thermal analysis, Boehm´s method, SEM and HRTEM. All the results led to the conclusion that carbon materials are characterized by well-developed micro-mesoporous structure. Carbon materials CP3 had a spherical structure, and possess only acidic functional groups on surface. However, carbon nanotubes had different physicochemical parameters: length and diameter of the tube, number of the walls, the value of the BET surface area. The results indicated the amphoteric nature due to simultaneous presence of acidic and basic groups. Obtained results of adsorption-desorption using the flow method showed that studied carbon materials are good phenol and paracetamol adsorbents. A correlation was observed between the amount of acid groups and the amount adsorbates on CP3materials. The impact of the chemical nature of carbon CP3 on kinetics of sorption processes was also demonstrated. However, the amounts of organic compounds adsorbed on carbon nanotubes increased with the values of the BET surface area. The highest sorption capacity of studied adsorbates was recorded for carbon nanotubes with the highest values of the BET surface area. It has been shown, that the molecules are adsorbed parallely on the surface of carbon nanotubes, since this arrangement rises up the energy dispersive interactions between aromatic ring of the phenol or paracetamol molecules and a carbon matrix. The results of numerous study and computer simulations clearly indicate that paracetamol molecules form nanoaggregates in the interstitial channels between nanotubes and in the pores of activated carbons. Therefore a new method is proposed for thermal deposition (so-called Hot Melt Deposition HMD) of paracetamol on carbon materials. The method of carbonaceous material heating with adsorbed drug at high temperatures can be successfully applied for the preparation of new drug delivery systems with varying properties. New drug delivery systems were characterized by a variable rate of paracetamol release and a wide range of desorbed amount of the drug. The porous structure of carbon materials used affects the kinetics of release. Carbon nanotubes have been very promising material that can be used as support of drugs in delivery system. In the case of activated carbons better properties exhibit materials with higher content of mesopores. Performed MTT tests of nanotubes and drug-loaded nanotubes show that the observed decrease in cell viability number is caused by the influence of the cytostatic properties of nanotubes - they inhibit the proliferation of cells. Studied carbon nanotubes are essentially nontoxic. Obtained results led to the conclusion that carbon materials can be used as potential carriers of paracetamol.