# Bioactive Glass as a Nanoporous Drug Delivery System for Teicoplanin  
[PERSON]  
1 Center for Fundamental Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan  
2 School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan; [EMAIL_ADDRESS] (W.F.); [EMAIL_ADDRESS] (B.-R.H.); [EMAIL_ADDRESS] (Y.-H.W.)  
[PERSON]  
2 School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan  
for antibacterial effects [2], strontium (Sr) for bone growth [3], and magnesium (Mg) for bone mineralization [3]. Boron (B) can influence bone growth and can act as a nutrition component to enhance bone strength under compression [4]. It improves bone health, stimulates wound healing, and has been demonstrated to increase bioactivity.  
Bioactive glass (BG) is a biomaterial based on SiO\({}_{2}\), Na\({}_{2}\)O, CaO, and P\({}_{2}\)O\({}_{5}\)[5]. BG is rich in calcium and phosphorus, the main inorganic components of bones and teeth. Calcium phosphate can be absorbed into cells through endocytosis and dissolved in the lysosome, causing its membrane to rupture. The subsequent release of calcium ions into the cytoplasm will increase the intracellular calcium concentration and stimulate the release of exosomes [6]. Calcium phosphate can be made into nanorods and nanowires, and applied in intracellular protein delivery or used as a building block for the development of artificial bone [7]. Drugs can be added to the calcium and phosphorous apatite particles, resulting in many calcium and phosphorus ions and causing osmotic pressure changes. This induces the breakdown of lysosomes and leads to drug release into the cytoplasm. These inorganic materials act as long-acting drug carriers [8]. Mesoporous BG could be further developed as a drug delivery system for gentamicin and ampicillin. The combination of mesoporous BG with drugs could act as a multifunctional delivery platform to improve osteogenesis and antibacterial activity [9].  
B-doped BG has significant effects on the structural, physiochemical, and biological properties related to tissue regeneration [10]. Boron trioxide could be added to BG using the traditional melt and quench process [11]. The glass transition temperature and crystallization onset temperature of BG decreased as the amount of B increased, and B-doped BG was shown to have better hot working properties during scaffold processing without crystallization. [12]. Using sol-gel methods, porous mesopore B-doped BG scaffolds were prepared for dexamethasone delivery. B-doped BG improved the proliferation and bone-related gene expression of osteoblasts, and it also maintained the sustained release of dexamethasone over a long-term span. [13]. Mesoporous B-doped BG is a promising biomaterial with improved mechanical properties [14].  
Teicoplanin and vancomycin are the last lines of antibiotic defense for severe infections with Gram-positive bacteria. They have the strongest antibacterial effect, but teicoplanin has a lower renal toxicity and longer half-life. It is administered intramuscularly or intravenously once a day, so it is a valuable alternative to vancomycin [15]. Teicoplanin is suitable for the treatment of endocarditis, osteomyelitis, pneumonia, septicemia, soft tissue infection, enteritis, and clostridial infection caused by staphylococcal infection [16]. BG was initially developed as a scaffold for bone repair materials, so BG can be mixed with teicoplanin to form a teicoplanin/BG composite to place in the repair region [17].  
In this study, BG was developed by the sol-gel method as a drug delivery system for teicoplanin. Various B concentrations were used to tune the physicochemical properties of BG. The feasibility of using BG and B-doped BG materials as drug delivery systems was evaluated.