Bone cements represent an innovative and versatile class of materials in the field of biomedical engineering for bone tissue repair, particularly in the treatment of patients affected by osteoporosis and other disabling diseases that prevent spontaneous bone regeneration. This thesis project investigates several properties of struvite-based trimagnesium phosphate bone cements (TMPCs), a subclass of magnesium phosphate cements (MPCs), as an alternative to the more traditional brushite-based calcium phosphate cements (CPCs). Various cements were prepared starting from Mg₃(PO₄)₂, synthesized through solid-state synthesis, to which ammonium phosphate solutions at different concentrations and in different amounts were added. This resulted in a series of cements subsequently loaded with meloxicam, an anti-inflammatory drug useful during the early post-operative stages to limit potential inflammation. Several aspects were investigated: • The exploration of different cement synthesis methods, including liquid- and solid-state routes. • The study of phase transitions during cement formation and aging over a time frame ranging from 24 hours to 31 days. • The investigation of the physical and structural properties, as well as the mechanical strength, of the cements immediately after preparation and at the end of the aging period. • The evaluation of the use of these cements as drug-delivery systems for meloxicam through release tests carried out in an environment simulating physiological conditions. The initial aim of the project was to demonstrate the compatibility of TMPC systems with an antibiotic or anti-inflammatory drug, thereby showing their active role in bone tissue healing in addition to their structural function. It also aimed to demonstrate the versatility of drug release by modulating the final cement structure through the addition of ammonium phosphate at different powder-to-liquid (P/L) ratios and concentrations. Subsequently, the discovery of dehydration phenomena and the development of new phases during the cement maturation process shifted the focus of the project toward the possibility of optimizing the material according to both structural and therapeutic requirements. In particular, the work sought to identify the appropriate balance between mechanical strength and complete, controlled drug release, as both aspects are related to the final porosity of the material.
I cementi ossei rappresentano, nel campo dell’ingegneria biomedica, una categoria di materiali innovativa e versatile nella riparazione del tessuto osseo, specialmente per il trattamento di pazienti affetti da osteoporosi e altre malattie invalidanti che rendono impossibile la rigenerazione spontanea dell’osso. Nel seguente progetto di tesi, viene proposto uno studio su diverse proprietà dei cementi ossei di trimagnesio fosfato (TMPCs) a base di struvite, una sottocategoria dei cementi di magnesio fosfato (MPCs), in sostituzione dei più tradizionali cementi ossei di calcio fosfato (CPCs) a base di brushite. Sono stati quindi preparati vari cementi a partire da Mg3(PO4)2, sintetizzati mediante sintesi a stato solido, a cui veniva aggiunta una soluzione di fosfato di ammonio a diverse concentrazioni e in quantità differente, ottenendo una serie di cementi successivamente caricati con meloxicam, un farmaco antiinfiammatorio, utile nelle prime fasi post-operatorie per limitare la possibile infiammazione. Sono stati affrontati vari aspetti: • l’esplorazione di vari metodi sintetici dei cementi, tra cui metodi per via liquida e solida • lo studio delle transizioni di fase durante la formazione e l’invecchiamento del cemento, in un arco temporale che spazia tra le 24 ore e i 31 giorni • lo studio delle proprietà fisiche e strutturali e della resistenza meccanica dei cementi appena preparati e al termine dell’invecchiamento • valutazione dell’impiego dei cementi come sistemi per il drug delivery del farmaco Meloxicam tramite prove di rilascio in ambiente che simulava quello fisiologico L’obiettivo iniziale del progetto era quello di mostrare la compatibilità dei sistemi di TMPCs con un farmaco antibiotico o antiinfiammatorio, in modo da dimostrare il loro ruolo attivo nella guarigione del tessuto osseo, oltre che strutturale, e di mostrare la versatilità nel rilascio del farmaco, modulando la struttura finale del cemento tramite l’aggiunta di fosfato di ammonio in diversi rapporti liquido/polvere (P/L) e diverse concentrazioni. Successivamente, la scoperta di fenomeni di disidratazione e lo sviluppo di nuove fasi nel corso del processo di maturazione dei cementi ha portato l’attenzione del progetto sulla possibilità di ottimizzare il materiale sia in base a necessità strutturali che terapeutiche, ricercando il giusto compromesso tra la resistenza meccanica e il rilascio completo e controllato di farmaco, aspetti entrambi correlati alla porosità finale del materiale.
Cementi di trimagnesio fosfato come sistemi per il drug delivery: studio dell'evoluzione delle fasi e delle proprietà meccaniche e fisiche
ROSSINI, MATTEO
2025/2026
Abstract
Bone cements represent an innovative and versatile class of materials in the field of biomedical engineering for bone tissue repair, particularly in the treatment of patients affected by osteoporosis and other disabling diseases that prevent spontaneous bone regeneration. This thesis project investigates several properties of struvite-based trimagnesium phosphate bone cements (TMPCs), a subclass of magnesium phosphate cements (MPCs), as an alternative to the more traditional brushite-based calcium phosphate cements (CPCs). Various cements were prepared starting from Mg₃(PO₄)₂, synthesized through solid-state synthesis, to which ammonium phosphate solutions at different concentrations and in different amounts were added. This resulted in a series of cements subsequently loaded with meloxicam, an anti-inflammatory drug useful during the early post-operative stages to limit potential inflammation. Several aspects were investigated: • The exploration of different cement synthesis methods, including liquid- and solid-state routes. • The study of phase transitions during cement formation and aging over a time frame ranging from 24 hours to 31 days. • The investigation of the physical and structural properties, as well as the mechanical strength, of the cements immediately after preparation and at the end of the aging period. • The evaluation of the use of these cements as drug-delivery systems for meloxicam through release tests carried out in an environment simulating physiological conditions. The initial aim of the project was to demonstrate the compatibility of TMPC systems with an antibiotic or anti-inflammatory drug, thereby showing their active role in bone tissue healing in addition to their structural function. It also aimed to demonstrate the versatility of drug release by modulating the final cement structure through the addition of ammonium phosphate at different powder-to-liquid (P/L) ratios and concentrations. Subsequently, the discovery of dehydration phenomena and the development of new phases during the cement maturation process shifted the focus of the project toward the possibility of optimizing the material according to both structural and therapeutic requirements. In particular, the work sought to identify the appropriate balance between mechanical strength and complete, controlled drug release, as both aspects are related to the final porosity of the material.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.14239/36564