The effect of ionizing radiation on chloramphenicol

Abstract

The effect of ionizing radiation on the physicochemical properties of chloramphenicol in solid state has been studied. The compound was e-beam irradiated with doses from the range 25-400 kGy and the possible changes were detected in the organoleptic methods (colour, form, odour, solubility and clarity), by SEM observations, X-ray, chromatography (TLC), spectrophotometry (UV, IR, EPR) and thermal (DSC) methods.No significant changes relative to the unirradiated sample were observed as a result of irradiation with the dose of 25 kGy -a standard dose for radiation sterilization, besides free radicals generation. Higher doses were found to produce a change in colour, increase in absorbance (UV), changes in the XRD spectra and appearance of products of radiolysis. The presence of the radiolysis products was confirmed by the TLC method, indirectly by DSC showing a decrease in the melting point from 0.2 to 4.5°C and enthalpy from 3.8 to 23.3 J g -1 , respectively. A linear relationship was obtained between the irradiation dose (25-400 kGy) and the melting point of chloramphenicol, characterised by the correlation coefficient r=0.9968.The EPR signal intensity increased with increasing dose of irradiation and the lifetime of the free radicals was longer than 6 months. No changes were detected in SEM and IR spectra.As follows from our results, the DSC method is most suitable for a fast monitoring of the drugs subjected to sterilization by irradiation as it permits detection of changes occurring even on irradiation with low doses and their quantitative description.

Thermal study of four irradiated imidazoline derivatives in solid state

“…The DSC method has been also appreciated by the authors working on evaluation of stability of therapeutic substances [13][14][15][16][17][18][19]. It has been successfully applied in estimation of the thermal [13], photochemical [14] and radiochemical stability of drugs [15][16][17][18][19][20][21]. Determination of the radiochemical stability of therapeutic substances (and emollients) has become of increasing importance in view of growing application of radiation sterilisation, an effective method of sterilisation and decontamination of drugs [22].…”

“…Determination of the radiochemical stability of therapeutic substances (and emollients) has become of increasing importance in view of growing application of radiation sterilisation, an effective method of sterilisation and decontamination of drugs [22]. Particularly important is determination of the radiochemical stability of therapeutic substances being components of eye drops and ophthalmic ointments [21], injections and infusion fluids and drugs applied to open injuries and burns as they must be sterile [22,23]. The four selected derivatives of imidazoline show antihistamine activity (AN, TM) or a-adrenergic activity (NN, XM).…”

Two-Step Solid Lipid Extrusion as a Process to Modify Dissolution Behavior

“…One combined melting endotherm for the matrix can be detected with an onset of about 62°C (32,33). The melting endotherm of the drug was less defined (onset 114°C) as the drug partially dissolved into the molten polyethylene glycol as already stated above (34). In conclusion, two-step extrusion including initial extrusion of drug and one matrix component followed by the extrusion of the milled extrudates with the second matrix component in powdered form leads to stable extrudates that exhibit the same solid-state behavior.…”

“…for chloramphenicol in the literature (32)(33)(34). Figure 1b depicts the corresponding extrudates produced using the three powdered substances.…”

“…The sharp melting endotherm (onset 151°C) suggests that the drug chloramphenicol remained in its stable crystalline form (34) in the tripalmitin extrudate (Fig. 1b).…”