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Surface-modified phillipsite-rich tuff from the Campania region (southern Italy) as a promising drug carrier: An ibuprofen sodium salt trial


Mariano Mercurio1,*, †, Francesco Izzo1 , Alessio Langella1 , Celestino Grifa1 , Chiara Germinario1 , Aleksandra Daković2 , Paolo Aprea3 , Rossana Pasquino3 , Piergiulio Cappelletti4 , Fabio Sossio Graziano4 , and Bruno de Gennaro3

American Mineralogist, Volume 103, pages 700–710, 2018
1 Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Via De Sanctis, 82100 Benevento, Italy
2 Institute for Technology of Nuclear and Other Mineral Raw Materials, Franche d’ Epere 86, 11000 Belgrade, Serbia
3 DICMAPI, Federico II University, Piazzale V. Tecchio 80, 80125 Naples, Italy
4 Department of Earth Sciences, Environment and Resources, Federico II University, via Cinthia, 80126, Naples, Italy
The encapsulation and delivery of drugs often involves the use of expensive microporous materials, and we have investigated the potential for natural zeolites from the widespread volcanic formations of southern Italy as alternatives to these carriers. Surface-modified natural zeolites (SMNZs) with diverse micellar structures (patchy and complete bilayers) were obtained by using different cationic surfactants [cetylpyridinium chloride (CP-Cl), benzalkonium chloride (BC-Cl), hexadecyltrimethylammonium chloride (HDTMA-Cl), and bromide (HDTMA-Br) with phillipsite-rich tuff from the Campania region (southern Italy)]. Loading and release kinetics tests of sodium ibuprofen (IBU) were carried out with organo-phillipsite composites using Fourier transform infrared spectroscopy (FTIR) and thermal analysis coupled with evolved gas analysis (EGA). Results from these tests were mathematically modeled to evaluate IBU adsorption and release mechanisms. The maximum loaded amount of IBU was attained for organo-phillipsite modified with HDTMABr (PHB), which showed a complete bilayer micellar structure. Whenever a patchy bilayer micellar structure formed, the lowest adsorptions of IBU were observed. Equilibrium adsorption results were fit using Langmuir, Sips, and Toth models. Pseudo-first-order and pseudo-second-order fits to the loading kinetic data provided significant goodness of fit. Good fits to the release kinetic data were obtained using first-order and Weibull equations, shedding new light on the release mechanism of IBU from phillipsite. The active amount of IBU on the modified zeolite surface was almost totally available for pharmaceutical purposes.
Keywords: Phillipsite, Neapolitan Yellow Tuff, ibuprofen sodium salt, functionalization, SMNZ, carrier, drug delivery, Sips model, Toth model; Microporous Materials: Crystal-Chemistry, Properties, and Utilizations