Synthesis of Hydroxyapatite/Bioglass Composite Nanopowder Using Design of Experiments

Abstract

Composite scaffolds of hydroxyapatite (HAp) nanoparticles and bioactive glass (BG) were applied as an appropriate selection for bone tissue engineering. To this end, HAp/BG composite was synthesized by a hydrothermal method using Design of Experiments (DOE) with a combined mixture–process factor design for the first time. The input variables were hydrothermal temperature at three levels (i.e., 100, 140, 180 °C) as a process factor and two mixture components in three ratios (i.e., HAp 90, 70, 50; BG 50, 30, 10). The degree of crystallinity and crystal size in the composite were the output variables. XRD showed that only a small fraction of BG was crystallized and that a wollastonite phase was produced. The XRD results also revealed that incorporation of Si into the HAp structure inhibited HAp crystal growth and restricted its crystallization. The FTIR results also showed that the intensity of the hydroxyl peak decreased with the addition of silicon into the HAp structure. DOE results showed that the weight ratio of the components strongly influenced the crystal size and crystallinity. SEM and FTIR results identified the greatest bioactivity and apatite layer formation in the Si-HAp sample with an HAp70/BG30 ratio after 14 days immersion in simulated body fluid (SBF) solution, as compared to other ratios and HAp alone. Therefore, the combination of HAp and BG was able to yield a HAp/BG composite with significant bioactivity.

Enteric-coating film effect on the delayed drug release of pantoprazole gastro-resistant generic tablets

“… 60 , 75 , 76 However, differences in band transmittance were observed between the generic and brand samples, which could be attributed to the presumed presence of impurities in the generic PNZ product. 55 , 76 – 77 These findings are consistent with previous literature that reported no alteration in the band position for PNZ in the formulation, except for the band transmittance. 55 Raman spectra for all three samples showed comparable results to the FTIR, further supporting the concept that the differences observed in the FTIR spectra of the generic and brand products might be due to the presence of impurities.…”

Galvanic Deposition of Calcium Phosphate/Bioglass Composite Coating on AISI 316L

“…The absence of a Si peak is due to the coating's dissolution in SBS. As reported in [103], the dissolution processes of composite coatings are quicker than pure calcium phosphate and Bioglass coatings. These high dissolution rates lead to rapid supersaturation at the coating/SBF interface and thus to the rapid precipitation of the hydroxyapatite phase [104].…”

“…The addition of Bioglass in the solution causes a further decrease in the main grain sizes. This behavior is due to the incorporation of Bioglass in the calcium phosphate deposit, which continuously stimulates the formation of new nucleation sites and limits crystal growth [103]. The low crystallinity of the composite coating (which corresponds to a high level of reactivity and, therefore, a high dissolution/reprecipitation rate) is another reason for its high bioactivity in SBF [105].…”