Several authors have studied the release profile of drugs incorporated in different devices. However, to the best of our knowledge, although many studies have been done on the release of tetracycline, in these release devices, no study has investigated if the released compound is actually the tetracycline, or, instead, a degraded product. This approach is exploited here. In this work, we analyse the influence of two drying methods on the tetracycline delivery behaviour of synthesised glasses using the sol-gel process. We compare the drying methods results using both theoretical models and practical essays, and analyse the chemical characteristic of the released product in order to verify if it remains tetracycline. Samples were freeze-dried or dried in an oven at 37°C and characterised by several methods such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TG), differential thermogravimetric analysis (DTG), differential thermal analyses (DTA) and gas adsorption analysis (BET). The released concentration of tetracycline hydrochloride was studied as a function of time, and it was measured by ultraviolet spectrophotometry in the tetracycline wavelength. The drug delivery profiles were reasonably consistent with a diffusion model analysis. In addition, we observed higher release rates for the freeze-dried compared to those dried in an oven at 37°C. This higher release can be attributed to larger pore size for the freeze-dried sample systems with tetracycline, which promoted more water penetration, improving the drug diffusion. The analysis of the solution obtained in the release tests using high-performance liquid chromatography- mass spectrometry (HPLC-MS) confirmed that tetracycline was being released.
release drug drying diffusion model glass tetracycline
This is a preview of subscription content, log in to check access
This work was supported by CNPq and FAPEMIG (including grant # APQ-00651-11), Brazil.
Blanchflower WJ, McCracken RJ, Haggan AS, Kennedy DG. Confirmatory assay for the determination of tetracycline, oxytetracycline, chlortetracycline and its isomers in muscle and kidney using liquid chromatography mass spectrometry. J Chromatogr B. 1997;692(2):351–60. https://doi.org/10.1016/S0378-4347(96)00524-5.CrossRefGoogle Scholar
Lambs L, Decocklereverend B, Kozlowski H, Berthon G. Metal ion-tetracycline interactions in biological-fluids. 9. Circular-dichroism spectra of calcium and magnesium complexes with tetracycline, oxytetracycline, doxycycline, and chlortetracycline and discussion of their binding modes. Inorg Chem. 1988;27(17):3001–12. https://doi.org/10.1021/ic00290a022.CrossRefGoogle Scholar
Machado FC, Demicheli C, Garnier-Suillerot A, Beraldo H. Metal-complexes of anhydrotetracycline. 2. Absorption and circular-dichroism study of Mg(II), Al(III), and Fe(III) complexes Possible influence of the Mg(II) complex on the toxic side-effects of tetracycline. J Inorg Biochem. 1995;60(3):163–73. https://doi.org/10.1016/0162-0134(95)00017-I.CrossRefPubMedGoogle Scholar
Godbout N, Salahub DR, Andzelm J, Wimmer E. Optimization of gaussian-type basis-sets for local spin-density functional calculations. 1. Boron through neon, optimization technique and validation. Can J Chem. 1992;70(2):560–71. https://doi.org/10.1139/v92-079.CrossRefGoogle Scholar
Langer RS, Wise DL. Medical applications of controlled release, vol. I. Boca Raton: CRC-Press; 1984. p. 42–65.Google Scholar
Wlosnewski JC, Kumpugdee-Vollrath M, Sriamornsak P. Effect of drying technique and disintegrant on physical properties and drug release behavior of microcrystalline cellulose-based pellets prepared by extrusion/spheronisation. Chem Eng Res Des. 2010;88(1):100–8. https://doi.org/10.1016/j.cherd.2009.07.001.CrossRefGoogle Scholar
Jalvandi J, White M, Truong YB, Gao Y, Padhye R, Kyratzis IL. Release and antimicrobial activity of levofloxacin from composite mats of poly(ɛ-caprolactone) and mesoporous silica nanoparticles fabricated by core–shell electrospinning. J Mater Sci. 2015;50(24):7967–74. https://doi.org/10.1007/s10853-015-9361-x.CrossRefGoogle Scholar
Sing KSW, Everett DH, Haul RAW, Moscou L, Pierotti RA, Rouquerol J, et al. Reporting physisorption data for gas solid systems with special reference to the determination of surface-area and porosity (recommendations 1984). Pure Appl Chem. 1985;57:603–19. https://doi.org/10.1351/pac198254112201.CrossRefGoogle Scholar
Mohammed-Ali MAJ. Stability study of tetracycline drug in acidic and alkaline solutions by colorimetric method. J Chem Pharm Res. 2012;4:1319–26.Google Scholar
Lindsey ME, Meyer M, Thurman EM. Analysis of trace levels of sulfonamide and tetracycline antimicrobials in groundwater and surface water using solid-phase extraction and liquid chromatography/mass spectrometry. Anal Chem. 2001;73(19):4640–6. https://doi.org/10.1021/ac010514w.CrossRefPubMedGoogle Scholar