Effect of hydroxyapatite on the physicochemical characteristics of a gentamicin-loaded monoolein gel intended to treat chronic osteomyelitis

Abstract

Many works have demonstrated the real potential of gentamicin-monoolein-water formulations as bioresorbable and sustained-release implants for the local treatment of the chronic osteomyelitis. In order to improve the efficacy of this type of implant, the incorporation of hydroxyapatite, a well-known osteointegrator material, is thought to be an interesting approach. Five formulations incorporating 0, 2.5, 5, 10, and 20% of hydroxyapatite were examined with regard to their physicochemical and in vitro drug release characteristics. The rheological, thermal (differential scanning calorimetric and thermogravimetric diffraction analysis), X-ray diffraction, and dissolution studies have showed that the presence of hydroxyapatite does not dramatically disturb the cubic liquid crystalline structure of the monoolein-water gel and their ability to progressively release the antibiotic. Implant 20% that was capable to release gentamicin sulfate over a period of four weeks without marked burst effect could be used as a more suitable biodegradable delivery system for the local management of chronic osteomyelitis.

Physicochemical characterization and antimicrobial evaluation of gentamicin-loaded CaCO3 nanoparticles prepared via microemulsion method

“…No endo/exothermic peak was detected for GS-loaded CaCO 3 nanoparticles up to 350 °C (curves D) signifying that the drug was incorporated into the nanoparticles in an amorphous form. Similar observations have been reported by other authors for GS-loaded gels [62,67]. …”

“…According to curve (D), PXRD studies indicated that GS was loaded in its amorphous form into CaCO 3 nanoparticles during the precipitation (curve D). Similar observations have been reported by Sombie et al [67] and Semde et al [62] for GS-loaded gels. Figure 6.…”

“…PXRD analysis of the prepared samples are shown in Figure 5. PXRD patterns of GS (curve A) displayed no peak that was due to the amorphous nature of GS [62]. PXRD analysis also confirmed the existence of both calcite and vaterite polymorphs for the blank and drug-loaded [64].…”

“…Figure 6. Due to the amorphous nature of GS, no melting point was observed in its thermogram (curve A) [62,67]. The endothermic peak at about 100 °C for pure GS and its physical mixture with CaCO 3 nanoparticles was ascribed to the removal of physisorbed and chemisorbed water molecules [62,68].…”

Ciprofloxacin monoolein water gels as implants for the treatment of chronic osteomyelitis: In vitro characterization

“…[26] A similar release mechanism has also been reported from gentamicin[816] and clonidine[24] monoolein water gels respectively.…”