EFFECT OF ETHYLENE OXIDE STERILIZATION ON PLASTISIZER MIGRATION AND MECHANICAL AND BLOOD PROPERTIES OF MEDICAL GRADE POLYVINYLE CHOLORIDE

The use of phthalates as a plasticizer in plasticized polyvinyl chloride (PVC) always poses the threat of migration of phthalates into the environment through medical equipment. Phthalates can be used with natural-based plasticizers, such as Epoxidized soybean oil (ESBO) known as phthalate’s scavenger and PVC stabilizers. PVC formulations were characterized by different combinations of di (2-ethylhexyl) phthalate (DEHP) 30-40% with 5% ESBO. PVC flexibility increased significantly in the presence of ESBO, without a change in strength (tensile test). The decrease of the Tg temperature by adding ESBO in Differential Scanning Calorimetry indicated that ESBO preserved DEHP in the polymer. Also, it was shown that the sterilization process with Ethylene Oxide, similar to ESBO, decreased the Tg of polymer. DEHP migration was evaluated at a maximum level to the environment using the Gas Chromatography test. Samples containing ESBO showed less hemolysis. ABSTRAK: Penggunaan phthalates sebagai plasticizer dalam plastik polyvinyl chloride (PVC) selalu menimbulkan ancaman penghijrahan phthalates ke alam sekitar melalui peralatan perubatan. Phthalates boleh digunakan dengan plasticizer berasaskan semula jadi, seperti minyak kacang soya Epoxidized (ESBO) yang dikenali sebagai pemulung phthalate dan penstabil PVC. Formulasi PVC dicirikan oleh kombinasi yang berbeza di (2-ethylhexyl) phthalate (DEHP) 30-40% dengan 5% ESBO. Fleksibiliti PVC meningkat dengan ketara di hadapan ESBO, tanpa perubahan kekuatan (ujian tegangan). Penurunan suhu Tg dengan menambahkan ESBO dalam Calorimetri Pengimbasan Berbeza menunjukkan bahawa ESBO mengekalkan DEHP dalam polimer. Juga, ditunjukkan bahawa proses pensterilan dengan Etilena Oksida, serupa dengan ESBO, menurunkan Tg polimer. Penghijrahan DEHP dinilai pada tahap maksimum ke lingkungan menggunakan uji Kromatografi Gas. Sampel yang mengandungi ESBO menunjukkan kurang hemolisis.

Ethylene oxide sterilization of electrospun poly(l-lactide)/poly(d-lactide) core/shell nanofibers

The application of polymers in medicine requires sterilization while retaining material structure and properties. This demands detailed analysis, which we show exemplarily for the sterilization of PLLA/PDLA core–shell nanofibers with ethylene oxide (EtO). The electrospun patch was exposed to EtO gas (6 vol% in CO2, 1.7 bar) for 3 h at 45 °C and 75% rel. humidity, followed by degassing under pressure/vacuum cycles for 12 h. GC–MS analysis showed that no residual EtO was retained. Fiber diameters (~ 520 ± 130 nm) of the patches remained constant as observed by electron microscopy. Young’s modulus slightly increased and the elongation at break slightly decreased, determined at 37 °C. No changes were detected in 1H-NMR spectra, in molar mass distribution (GPC) or in crystallinity measured for annealed samples with comparable thermal history (Wide Angle X-Ray Scattering). Altogether, EtO emerged as suitable sterilization method for polylactide nanofibers with core–shell morphology. Graphic abstract

Use of Overkill Half-Cycle Qualification Data to Support Reduction of Exposure Time in Validated Ethylene Oxide Sterilization Cycles

This article details the evaluation conducted for the potential to reduce ethylene oxide (EO) exposure times using data from currently validated EO sterilization cycles. The candidate cycles used the overkill half-cycle approach detailed in Annex B of ANSI/AAMI/ISO 11135:2014. The overkill half-cycle approach is conservative and has been the method of choice with medical device manufacturers because of its ease of understanding. The analysis presented provides an understanding of the extent of this conservative nature. Based on the analysis, exposure time can be reduced and rapidly implemented. The reduction in the exposure time may improve the product EO residuals and allow for additional time for the EO processing chamber to be utilized and/or for additional off-gassing for the product, if needed.

Ethylene Oxide Sterilization of TiN/TiO2 Coated Titanium Implant Material

The goal of this work is to evaluate a common final sterilization technique with EtO by measuring its effect on the physicochemical properties of PVD deposited TiN/TiO2 coatings on Ti-5Al-4V alloy. As the effectiveness of EtO sterilization corresponds to the operation parameters (temperature, duration, humidity, etc.), two different exposure cycles (cool (MS) at 37 °C for 220 min gas expose and warm (SS) at 55 °C for 100 min expose) were examined. SEM analysis revealed that the surface morphology of the coatings was not changed after both MS and SS treatments. In contrast to Ti 2p and O 1s peaks determined by XPS analysis, C 1s peak of TiO2 layer decreased with increasing sterilization temperature while the percentage contribution of Ti-OH in O 1s increased. This affected the surface hydrophilicity and free energy that increased from 47.37 for the control sample to 50.77 mJ m-2 in the case of SS specimen. Additionally, EtO sterilized samples demonstrated decreased values of corrosion and passivation current densities in simulated body fluid (pH 7.4) at 37 ± 0.05 °C as opposed to the control sample. The results indicate the suitability of both mild and severe EtO sterilization methods for improvement of the desired physicochemical properties of gradient TiN/TiO2 coatings.