The thesis is focused on the synthesis of a solid formulation and coating of Octenidine microparticles with a controlled size and release rate using biodegradable polymers for biomedical applications. Octenidine is a modern antiseptic, which was thought to substitute antibiotics in surgical operations because of its drastic effectiveness against resistant pathogens. The goal of the research was to design a system to control the release of the drug, once applied to the surgical site either for avoiding toxic concentration or for protecting the site against infections within a specific period. In the last decades, the possibility of using biocompatible polymers as drug carriers was brought to the attention of many scientists, who have striven to design polymeric solid formulations with specific degradation mechanisms and mechanical properties to control the release. In this study, polyester-based brush hydrophobic polymers were synthesized via Ring Opening Polymerization (ROP) followed by a functionalization reaction and a subsequent Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. Four methods were developed for the particles formulation and coating, based on different technologies: (1) Coprecipitation, (2) Sonofragmentation-Precipitation, (3) W/O emulsion by sonication, (4) Spray drying. Furthermore, an in-depth study over release profiles of microparticles was performed to demonstrate the possibility to control the release mechanism and rate of the drug by varying the encapsulation efficiency. Eventually, the antimicrobial activity of the polymer, drug and product was tested in vitro on Staphylococcus Epidermidis.
Alla base di questo lavoro di tesi vi è la sintesi di microparticelle solide di Octenidina e polimeri biodegradabili di dimensioni e velocità di rilascio controllate per applicazioni biomediche. L’Octenidina è un moderno antisettico considerato un ottimo candidato per applicazioni chirurgiche, grazie alla sua drastica efficacia contro patogeni che presentano resistenza agli antibiotici correntemente utilizzati. L’obiettivo della ricerca è la progettazione di un sistema per controllare il rilascio del farmaco una volta applicato sul sito chirurgico, sia per evitare concentrazioni tossiche, sia per la protezione a lungo termine del sito contro le infezioni. Negli ultimi decenni la possibilità di utilizzare polimeri biocompatibili come vettori di composti terapeutici ha riscosso l’interesse di molti scienziati che hanno tentato di progettare formulazioni polimeriche solide con meccanismi di degradazione e proprietà meccaniche specifici per il controllo dei tempi di rilascio. In questo studio poliesteri idrofobici tipo “brush” sono stati sintetizzati tramite Ring Opening Polymerization (ROP), seguita da una reazione di funzionalizzazione del macromonomero e una successiva Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. Sono quindi stati sviluppati quattro metodi per la formulazione e il coating delle particelle basati su principi differenti: (1) Coprecipitazione, (2) Sonoframmentazione-Precipitazione, (3) Emulsione W/O via sonicazione, (4) Spray drying. È stato svolto in seguito uno studio approfondito dei profili di rilascio delle microparticelle per dimostrare la possibilità di controllarne il meccanismo e le tempistiche modificando l’efficienza di incapsulazione. Infine è stata testata in vitro l’attività antimicrobica del polimero, del farmaco e del prodotto finale su batteri di tipo Staphylococcus Epidermidis.
Development of a process for solid formulation and coating of antiseptic microparticles
PIVIALI, CAMILLA
2017/2018
Abstract
The thesis is focused on the synthesis of a solid formulation and coating of Octenidine microparticles with a controlled size and release rate using biodegradable polymers for biomedical applications. Octenidine is a modern antiseptic, which was thought to substitute antibiotics in surgical operations because of its drastic effectiveness against resistant pathogens. The goal of the research was to design a system to control the release of the drug, once applied to the surgical site either for avoiding toxic concentration or for protecting the site against infections within a specific period. In the last decades, the possibility of using biocompatible polymers as drug carriers was brought to the attention of many scientists, who have striven to design polymeric solid formulations with specific degradation mechanisms and mechanical properties to control the release. In this study, polyester-based brush hydrophobic polymers were synthesized via Ring Opening Polymerization (ROP) followed by a functionalization reaction and a subsequent Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. Four methods were developed for the particles formulation and coating, based on different technologies: (1) Coprecipitation, (2) Sonofragmentation-Precipitation, (3) W/O emulsion by sonication, (4) Spray drying. Furthermore, an in-depth study over release profiles of microparticles was performed to demonstrate the possibility to control the release mechanism and rate of the drug by varying the encapsulation efficiency. Eventually, the antimicrobial activity of the polymer, drug and product was tested in vitro on Staphylococcus Epidermidis.| File | Dimensione | Formato | |
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2018_10_Piviali.pdf
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https://hdl.handle.net/10589/142732