Linear release of strontium ions from high borate glasses via lanthanide/alkali substitutions

High Borate Networks as a Platform to Modulate Temporal Release of Therapeutic Metal Ions Gallium and Strontium

“…With appropriate compositional modifications, the unique structural nature of vitreous Boron oxide may provide an innovative degradable platform for the controlled localized release of TMIs, Ga and Sr [3,9,12]. This is specifically related to the cation's concentration dependent ability to modulate the molecular structure of the network (i.e.…”

“…Contrary to historical concerns regarding borate glasses' low chemical durability, several compositions have recently displayed excellent potential in hard tissue and soft tissue augmentation/repair, specifically, enabling accelerated bone remodeling and healing of chronic wounds (e.g. diabetic ulcers) [1,7,[9][10][11][12]. An interesting characteristic of vitreous boron oxides is its complete degradation.…”

“…This concentration dependent modulation of glass properties is particularly useful as (i) many modifying cations have therapeutic potential, e.g. strontium (Sr) [12] and gallium (Ga) [19], and (ii) their inclusion in borate networks may orchestrate their subsequent controlled release under physiological conditions, whilst concurrently augmenting the degradation characteristics of the network as a whole. These features of borate networks may enable ".…”

Host responses to a strontium releasing high boron glass using a rabbit bilateral femoral defect model

“…In this context, borate glasses remain a major concern due to (i) low chemical durability, which may result in a biologically inappropriate degradation rate and (ii) the possible local toxic effects of borate ions (i.e., (BO 3 ) 3‐ ) in vivo . In a previous study pertaining to LB102, cumulative ion release of 400 ppm of B, 500 ppm of Sr, and 110 ppm of Na (La was undetectable) after 720 h extraction was determined . As a consequence of metal cation hydration and network hydrolysis (i.e., glass network degradation), the strong basicity of Sr(OH) 2 and NaOH within solution would most certainly increase the pH and consequently, a major concern related to these high levels of component ions are the rate by which they are released, as a rapid increase may induce an adverse host response, such as fibrotic encapsulation.…”

“…It was shown that decreasing La 2 O 3 :Na 2 O ratios enabled exacting control over glass degradation and ion release. In particular, one glass composition, LB102 (70B‐20Sr‐6Na‐4La, mol %), provided a linear release profile of Sr for up to the maximum extraction period of 720 h . Control of Sr release is important as it has been shown to provide for key cellular interactions that induce bone formation and inhibit bone resorption .…”