Sensitivity of hydrocortisone to gamma radiation in topical preparations

Radiation sterilization of new drug delivery systems

Radiation sterilization has now become a commonly used method for sterilization of several active ingredients in drugs or drug delivery systems containing these substances. In this context, many applications have been performed on the human products that are required to be sterile, as well as on pharmaceutical products prepared to be developed. The new drug delivery systems designed to deliver the medication to the target tissue or organ, such as microspheres, nanospheres, microemulsion, and liposomal systems, have been sterilized by gamma (γ) and beta (β) rays, and more recently, by e-beam sterilization. In this review, the sterilization of new drug delivery systems was discussed other than conventional drug delivery systems by γ irradiation.

Investigation of self-microemulsifying and microemulsion systems for protection of prednisolone from gamma radiation

Radiation is efficient for terminal sterilization. Unfortunately, its use for liquid pharmaceuticals is difficult. This work investigated the potential radioprotective effect of self-microemulsifying (SMEDDS), microemulsions and their phase transition systems which were reported to enhance ocular drug delivery. Prednisolone solutions were prepared in SMEDDS, W/O microemulsions containing, 5% w/w (ME 5%) or 10% w/w (ME 10%) water, liquid crystalline system with 25% water (LC) and coarse emulsion containing 80% water (EM). These were subjected to gamma irradiation with aqueous solution and suspension being used as control. The physical properties of the formulations were monitored and the chemical potency of the drug was determined using a stability indicating HPLC method. The phase behavior of the formulations was not affected by irradiation but the viscosity of LC was significantly reduced. The SMEDDS, ME 5% and ME 10% showed excellent radiation protection as indicated by no change in the chemical potency. The LC retained 84% and the EM retained 39.8% of the chemical potency after exposure to 20 KGy. The aqueous solution was extensively degraded with the suspension retaining only 73.5% of the potency at 20 KGy. SMEDDS and W/O microemulsion can thus protect prednisolone from degradation by ionizing radiation.