Ethylene Oxide Sterilization Research Articles

SG-APSIC1206: Effectiveness of sterilization practice in reprocessing medical devices among different multidisciplinary tertiary-care hospitals in Dhaka City

Objectives: Sterilization failure is one of the main causes of surgical-site infections. We assessed the effectiveness of the sterilization process of surgical instruments to determine the reasons for sterilization failure. Methods: In total, 100 sterilization cycles were observed from February 4, 2022, to September 5, 2022, in hospitals in Dhaka City. We used sterilization quality assurance monitoring tools (ie, biological indicators) for rapid steam and ethylene oxide sterilization methods. Tests were performed using an automatic reading machine, chemical indicator strips, and indicator tape for both steam and ethylene oxide methods. For laboratory testing and data collection, APSIC guidelines were followed. All samples were incubated for 48 hours to cross check the accuracy of the auto-reader result. Results: All ethylene oxide sterilization cycles were 100% successful, as shown by the rapid biological indicator (auto-reader), chemical indicator strips, and indicator tape. However, 22% sterilization failure occurred with steam sterilization, which was confirmed by the auto-reader, chemical indicator strips, and indicator tape. All biological samples showed no growth after 48 hours of incubation, except the sample from steam sterilization, which did show growth after 48 hours of incubation. Conclusions: We detected 22% steam sterilization failure, and serious harm to patients could occur if these surgical instruments were used for surgery. Process recall would not have been not possible if rapid biological indicator tests had not been performed and other chemical monitoring tools had not been used. The regular use of monitoring tools according to guidelines can be a reliable solution to reduce surgical site infections caused by inappropriate sterilization of surgical instruments.

Evaluation of Disinfection Methods for Artificial Plants in Zebrafish (Danio rerio) Recirculating Water Systems.

The use of artificial plants as environmental enrichment for zebrafish (Danio rerio) in biomedical research facilities has been shown to provide benefits in animal welfare and care. Despite the benefits of artificial plants to zebrafish welfare, some research facilities are hesitant to incorporate them into their routine husbandry practices due to concerns about disease transmission and a lack of guidance on effective disinfection practices between tanks. Limited published information is available on how to adequately disinfect artificial plants, which creates concerns regarding their reuse between tanks in recirculating water systems. Proper sanitation and disinfection of these items is crucial to preventing the spread of disease in the system. We evaluated 2 disinfection methods- a commercial-grade laboratory glassware dishwasher and an ethylene oxide (ETO) sterilizer-by using ATP detection and bacterial culture of the artificial plants before and after the disinfection process. Plants were placed in the dirty sump of 2 separate recirculating systems (2,500 to 3,000 fish per system) for 2 wk before the start of the study. High ATP levels and various bacterial organisms were detected prior to disinfection. The commercial-grade labo- ratory glassware dishwasher and ETO sterilizer both significantly reduced ATP levels and resulted in complete eradication of live bacteria that were present before treatment. This study demonstrates 2 effective methods for disinfecting artificial plants in zebrafish facilities.

Comparative studies of sterilization processes for sensitive medical nano-devices

Three-dimensional, open porous sensitive medical devices are increasingly attractive in biomedical engineering; at the same time new challenges immerse since traditional sterilization processes may not be appropriate for use with such sensitive devices. In the present study, we use a lyophilized nanostructured collagen sponge, as a model system of a sensitive medical device in order to study the effects of the two most common sterilization processes. Sterilization with gamma irradiation was found to cause profound effects on the internal structure illustrated by a change of the pore size from ca 70 μm to heterogeneous 40–560 μm. In contrast, ethylene oxide sterilization was seen to largely preserve the interior architecture, although it may alter permanently the surface properties of the sponge. This study helps to highlight the sterilization barriers that this kind of medical devices need to overcome.

Force degradation of orthodontic elastomeric chains: A literature review

Background: Elastomeric chains are used to generate force in many orthodontic procedures, but this force decays over time, which could affect tooth movement. This study aimed to study the force degradation of elastomeric chains. Data and Sources: An electronic search on Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, LILACS, and PubMed was made, only articles written in English were included, up to January 2022.Study selection: Fifty original articles, systematic reviews, and RCTs were selected. Conclusion: Tooth movement, salivary enzymes, alcohol-containing mouthwash, whitening mouthwash, and alkaline and strong acidic (pH <5.4) solutions all have a significant impact on elastomeric chain force degradation. The force level of elastomeric chains degrades rapidly over time; however, the force degradation rate is slower in thermoset chains than in thermoplastic ones. An efficient tooth movement could be achieved by using a thermoset chain type with monthly replacement. Ethylene oxide and gamma sterilization methods are preferred to avoid the risk of cytotoxicity.

Sterilization effects on poly(glycerol dodecanedioate): A biodegradable shape memory elastomer for biomedical applications.

Biodegradable shape memory polymers provide unique regenerative medicine approaches in minimally invasive surgeries. Once heated, thermally responsive shape memory polymer devices can be compressed, programmed to fit within a small profile, delivered in the cold programmed state, and expanded when heated to body temperature. We have previously developed a biodegradable shape memory elastomer (SME), poly(glycerol dodecanedioate) (PGD), with transition temperatures near 37°C exhibiting nonlinear elastic properties like numerous soft tissues. Using SMEs in the clinic requires disinfection and sterilization methods that conserve physiochemical, thermomechanical, and shape recovery properties. We evaluated disinfection protocols using 70% ethanol and UV254 nm for research applications and ethylene oxide (EtO) gas sterilization for clinical applications. Samples disinfected with ethanol for 0.5 and 1 min showed no changes in physiochemical material properties, but after 15 min showed slower recovery rates than controls (p < .05). EtO sterilization at 54.4°C decreased transition temperatures and shape recovery rate compared to EtO sterilization at 37.8°C (p < .01) and controls (p < .05). Aging samples for 9 months in a vacuum desiccator significantly reduced shape recovery, and the recovery rate in EtO sterilized samples compared to controls (p < .001). Cytotoxicity testing (ISO-10993.5C:2012) revealed media extractions from EtO sterilized samples, sterilized at 37.8°C, and high-density polyethylene negative control samples exhibit lower cytotoxicity (IC50) than Ethanol 1min, UV 2h, and EtO 54.4°C. Cell viability of NIH3T3 fibroblasts on sterilized surfaces was equivalent on EtO 37.7°C, EtO 54.4°C and Ethanol sterilized substrates. Finally, chromogenic bacterial endotoxin testing showed endotoxin levels were below the FDA prescribed levels for devices contacting blood and lymphatic tissues for ethanol 1min, UV 120 min, EtO 37.7°C, EtO 54.4°C. These findings outline various disinfection and sterilization processes for research and pre-clinical application and provide a pathway for developing custom sterilization cycles for the translation of biomedical devices utilizing PGD shape memory polymers.

Chemical vs thermal accelerated hydrolytic degradation of 3D-printed PLLA/PLCL bioresorbable stents: Characterization and influence of sterilization

Bioresorbable stents (BRS) are designed to provide initial sufficient mechanical support to prevent vessel recoil while being degraded until their complete resorption. Therefore, degradation rate of BRS plays a crucial role in successful stent performance. This work presents a complete study on the degradation of poly-l-lactic acid (PLLA) and poly(lactic-co-ɛ-caprolactone) (PLCL) stents fabricated by solvent-cast direct-writing (SC-DW) through two different accelerated assays: alkaline medium at 37 °C for 10 days and PBS at 50 °C for 4 months. On retrieval, degraded stents were characterized in terms of mass loss, molecular weight (Mw), thermal and mechanical properties. The results showed that under alkaline conditions, stents underwent surface erosion, whereas stents immersed in PBS at 50 °C experienced bulk degradation. Mn decrease was accurately described by the autocatalyzed kinetic model, with PLCL showing a degradation rate 1.5 times higher than PLLA. Additionally, stents were subjected to γ-irradiation and ethylene oxide (EtO) sterilization. Whereas EtO-sterilized stents remained structurally unaltered, γ-irradiated stents presented severe deterioration as a result of extensive chain scission.

The effect of source animal age, decellularization protocol, and sterilization method on bovine acellular dermal matrix as a scaffold for wound healing and skin regeneration.

Healing the full-thickness skin wounds has remained a challenge. One of the most frequently used grafts for skin regeneration is xenogeneic acellular dermal matrices (ADMs), including bovine ADMs. This study investigated the effect of the source animal age, enzymatic versus non-enzymatic decellularization protocols, and gamma irradiation versus ethylene oxide (EO) sterilization on the scaffold. ADMs were prepared using the dermises of fetal bovine or calf skins. All groups were decellularized through chemical and mechanical methods, unless T-FADM samples, in which an enzymatic step was added to the decellularization protocol. All groups were sterilized with ethylene oxide (EO), except G-FADM which was sterilized using gamma irradiation. The scaffolds were characterized through scanning electron microscopy, differential scanning calorimetry, tensile test, MTT assay, DNA quantification, and real-time PCR. The performance of the ADMs in wound treatment was also evaluated macroscopically and histologically. All ADMs were effectively decellularized. In comparison to FADM (EO-sterilized fetal ADM), morphological, and mechanical properties of G-FADM, T-FADM, and CADM (EOsterilized calf ADM) were changed to different extents. In addition, the CADM and G-FADM were thermally more stable than the FADM and T-FADM. Although all ADMs were noncytotoxic, the wounds of the FADM, T-FADM, and G-FADM groups were contracted to almost 30.0% of the original area on day 7, significantly faster than the CADM (17.5% ± 1.7) and control (12.2% ± 1.59) groups. However, by day 21, all ADMs were mostly closed except for the untreated group (60.1 ± 1.8). Altogether, fetal source and EO-sterilized samples performed better than calf source and gamma-sterilized samples unless in some mechanical properties. There was no added value in using enzymatic treatment during the decellularization process. Our results suggest that the age, decellularization, and sterilization methods of animal source should be selected based on the clinical requirements.

Study on Parametric Release of Ethylene Oxide Sterilization of Medical Devices

This study briefly introduces the basic theory of sterilization, the characteristics of ethylene oxide sterilization for medical devices and the key factors about sterilization effectiveness, analyzes and compares three methods used in the product release of medical devices sterilized by ethylene oxide: test for sterility, traditional release and parametric release, and focuses on the theoretical basis, feasibility, validation requirements, advantages and disadvantages of parametric release.

Validation of ethylene oxide sterilization of disposable electronic analgesia infusion pumps

Validation of ethylene oxide sterilization of disposable electronic analgesia infusion pumps

Study of Operative Outcomes of Hernioplasty Using Mosquito Net Mesh at a Tertiary Hospital.

BackgroundSynthetic mesh is the most efficient way to repair groin hernias. However, many patients in low and middle-income countries cannot afford the above-mentioned mesh. This study's goal was to describe the mosquito net mesh's (MNM) safety, viability, complications, and recurrence rate in hernioplasty done in rural populations.Material and methodsThis study was a single-centre, prospective, descriptive study, conducted in patients >18 years of age, of either gender, with unilateral or bilateral primary inguinal hernias (reducible/irreducible/bilateral hernia), admitted for elective or emergency open inguinal hernia mesh repair. The surgery was performed using reasonably priced (affordable to people of low socioeconomic status) polyethylene mosquito net mesh, which was cut into 8x16 cm rectangles and wrapped in two sealed plastic bags. They were sterilised using the ethylene oxide sterilisation (EtO) method. The type of hernia (unilateral or bilateral), post-operative pain, and complications were noted.ResultsAmong 400 study participants, the incidence of inguinal hernia was highest in the 60-79 year age group (51.5%). Direct inguinal hernia (67.5 %) was higher compared to indirect inguinal hernia (32.5 %). While a majority of the participants had a hernia on the right side (50%), 164 patients (41%) had a hernia on the left side, and 36 patients (9%) had a bilateral inguinal hernia. The average operative time for unilateral inguinal hernia was 73.96 minutes and for bilateral inguinal hernia was 106.66 minutes. Out of 400 patients, 355 patients (88.75%) had no complications. Among the postoperative patients, 14 patients (3.5%) experienced surgical site infection; 9 patients (2.25%) experienced headache; 5 patients (1.25%) experienced hematoma; 12 patients (3%) experienced urinary retention; and 5 patients (1.25%) experienced testicular pain. The average hospital stay of patients was 4.25 days. Patients returned to their daily activities and employment in an average of 7.29 days. The market cost of a single standard polypropylene mesh was Rs.1,660/-. For making a single mosquito net mesh of the same size, we had an expenditure of Rs. 11.83/- including the cost of sterilization. In this study, 382 patients (95.5%) gave us good feedback, 11 patients (2.75) gave satisfactory feedback, and 7 patients (1.75%) gave excellent feedback.ConclusionIn environments with limited resources, using mosquito net mesh for hernioplasty is reasonable, acceptable, doable, and economical.

Experimental study on the effect of selected sterilization methods on mechanical properties of polylactide FFF specimens

PurposeBiodegradable polymers are widely used in personalized medical devices or scaffolds for tissue engineering. The manufacturing process should be finished with sterilization procedure. However, it is not clear how the different sterilization methods have an impact on the mechanical strength of the three-dimensional (3D)-printed parts, such as bone models or personalized mechanical devices. This paper aims to present the results of mechanical testing of polylactide-based bone models before and after sterilization.Design/methodology/approachPolylactide specimens prepared in fused filament fabrication technology were sterilized with different sterilization methods: ultraviolet (UV) and ethylene oxide. Mechanical properties were determined by testing tensile strength, Young’s modulus and toughness.FindingsThe tensile strength of material after sterilization was significantly higher after ethylene oxide sterilization compared to the UV sterilization, but in both sterilization methods, the specimens characterized lower tensile strength and Young’s modulus when compared to the control. In comparison of toughness results, there was no statistically significant differences. The findings are particularly significant in the perspective of using individual implants, bone grafts and dental guides.Originality/valueAlthough fused filament fabrication (FFF) 3D printing devices equipped with UV light sterilization options are available, experimental results of the effect of selected sterilization methods on the mechanical strength of additively manufactured parts have not been described. This paper completes the present state of the art on the problem of sterilization of FFF parts from biodegradable materials.

Identification of residues in ethylene oxide sterilized hard gelatin capsule shells by gas chromatography-mass spectrometry and development of a simple gas chromatography-flame ionization detector method for the determination of residues

Four toxic residues in gelatin capsule shells after ethylene oxide (EO) sterilization were identified by gas chromatography-mass spectrometer (GC-MS) and they were ethylene oxide, 2-chloroethanol, acetaldehyde, and 1,4-dioxane. The generation pathway and mechanism of the 2-chloroethanol, acetaldehyde, and 1,4-dioxane were further investigated. Additionally, a simple and rapid gas chromatography-flame ionization detector (GC-FID) method was established and fully validation including specificity, linearity, sensitivity, and accuracy were conducted according to ICH Q2 (R1) guidelines. The results showed good linearities with coefficients (r) higher than 0.9999 for four analytes. The limits of detection (LODs) of four analytes were in the range of 0.025-1.0 μg·mL −1 and the limits of quantitation (LOQs) were in the range of 0.05-2.0 μg·mL −1 . The recoveries of four impurities were ranged from 83.0 % to 114.9 %. The repeatability and inter-day precisions were in the ranges of 0.7-3.3%. This validated GC-FID method provided an approach for capsule manufacturers to routinely monitor residues in gelatin capsule shells, design and optimize the storage time after sterilization and judge whether it can be released from the factory after sterilization. It can also be used for enterprises and regulatory bodies to routinely control the quality of hard gelatin capsule shells.

Improving the antithrombogenicity of nylon monofilament for surgical suture by coating a protease from Euphorbia resinifera latex

This study developed a method to improve the antithrombogenicity of a blue nylon monofilament suture (USP 3/0) by coating a plant serine protease purified from Euphorbia resinifera latex (EuRP-61) onto the surface of nylon using a combination of dipping and ultrasonication methods. EuRP-61 was a selected protease because the enzyme had been previously reported to have antithrombotic and anticoagulant activities, high stability and biological safety. Analyses of the fibrinogenolytic and fibrinolytic activities using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) and microwell plate assays revealed that the proper concentration of protease was 1 mg/ml for each coating of 20 strips of 10-mm nylon. The enzyme-coated nylon was disinfected by ethylene oxide (EO) sterilization. After EO sterilization, the enzyme-coated nylon presented fibrinogenolytic and fibrinolytic activities. Comparing the enzyme-coated and bare nylon, the enzyme-coated nylon prevented the human fibrin clot from adhering to its surface. In contrast, the fibrin clot stuck and was unable to be removed from the surface of the bare nylon. The antithrombogenicity of the protease-coated nylon evaluated in this study suggests its potential application as a surgical suture, especially for vessel anastomosis.

Biocomponents Based on Hydroxiapatite: Influence of Sterilization on the Mechanical Resistance.

Objective This study aimed to evaluate the influence of sterilization on the compressive and flexural mechanical strength of hydroxyapatite-based biocomponents obtained through freeze-dried bovine bone, and its association with chitosan. Methods Freeze-dried bovine bone was processed into 100 μm particles and mixed with 50% of its weight in chitosan. The mixture was packed in metallic molds for preparing the specimens, and sterilized at 127°C using an autoclave for subsequent experimentation. The specimens were subjected to compression and flexion tests following norm 5833 of the International Organization for Standardization (ISO), with 6 × 12 mm cylindrical blocks (for compression tests) and 75 × 10 × 3.3 mm plates (for flexion tests) as samples. The samples were divided into four groups of 20 specimens each, with 10 for compression and 10 for flexion tests. Three groups were sterilized (autoclave, gamma rays, and ethylene oxide), whereas the fourth group (control) was not. The mechanical tests obtained from the different sterilization processes were compared using analysis of variance (ANOVA, p < 0.05), followed by the Tukey multiple comparison test of means, with a 95% confidence interval. Results The specimens presented mean compressive strengths of 10.25 MPa for the control group and 3.67 MPa, 9.65 MPa, and 9.16 MPa after ethylene oxide, gamma ray, and autoclave sterilization, respectively. Flexion test results showed an average resistance of 0.40 MPa in the control group, and 0.15 MPa, 0.17 MPa, and 0.30 MPa after ethylene oxide, gamma ray, and autoclave sterilization, respectively. There were statistically significant differences observed in the maximum compression of the ethylene oxide-sterilized group compared with that of the control group ( p = 0 . 0002), gamma ray-sterilized ( p = 0.0003), and the autoclaved ( p = 0.0006) groups. There was a statistically significant difference in maximum flexion of the specimens sterilized by gamma rays when compared with the control group ( p = 0.0245). However, low flexural strengths were observed in all specimens. Conclusion The autoclave sterilization group did not result in statistically significant differences in either compression or flexion strength tests. Thus, the autoclave proved to be the best sterilization option for the hydroxyapatite-based biocomponents in this study.

Dynamic Obstruction due to Unfurling of Spirals in a Flexometallic Tube.

Flexometallic tubes are kink-resistant and extensively used in neurosurgeries. The manufacturers of flexometallic tubes recommend single usage. In low-income countries, due to the cost restraints, flexometallic tubes are commonly reused after ethylene oxide sterilization. With this technique, flexometallic tubes are effectively sterilized, but the physical integrity of the endotracheal tube cuffs may be compromised.1 Tube kinking2 and intraluminal blebs due to dissection3 are observed with the reused flexometallic tubes. These obstructions lead to difficulty in ventilation and inability to pass a suction catheter freely. Flexometallic tubes should be thoroughly checked for external deformity, cuff integrity, and tube patency for safe reuse.Despite thorough assessment of reused flexometallic tubes, the partial unfurling of nylon spirals with distal herniation into the tube (fig.) may still happen intraoperatively, leading to dynamic obstruction resulting in variable resistance during suction catheter negotiation (see Supplemental Digital Content 1, video S1, http://links.lww.com/ALN/C848). Along with the heavy weight of the circuit, the varied positions of head and neck result in additional rotational bending of flexometallic tubes, contributing to partial unfurling, which may not cause complete airway obstruction but can lead to difficult ventilation requiring airway change. The simple technique of passing a suction catheter through flexometallic tubes can help in identifying such partial tube obstruction. Reinforced tracheostomy tubes are also frequently reused after a thorough cleaning and visual inspection.Adhering to the manufacturer’s recommendation regarding reuse is the best way to prevent these complications. However, when clinically necessary and under the right circumstances only, flexometallic tubes should be reused after a thorough assessment.The authors are thankful to the patient who consented to publish the current article. The authors are also thankful to all anesthesia technicians who helped them ensure patient safety.The authors declare no competing interests.

Prospective Study Assessing Impact of Ethylene Oxide Sterilization on Endoscopic Ultrasound Image Quality

Duodenoscope-associated transmission of infections has raised questions about efficacy of endoscope reprocessing using high-level disinfection (HLD). Although ethylene oxide (ETO) gas sterilization is effective in eradicating microbes, the impact of ETO on endoscopic ultrasound (EUS) imaging equipment remains unknown. In this study, we aimed to compare the changes in EUS image quality associated with HLD vs HLD followed by ETO sterilization. Four new EUS instruments were assigned to 2 groups: Group 1 (HLD) and Group 2 (HLD+ ETO). The echoendoscopes were assessed at baseline, monthly for 6 months, and once every 3 to 4 months thereafter, for a total of 12 time points. At each time point, review of EUS video and still image quality was performed by an expert panel of reviewers along with phantom-based objective testing. Linear mixed effects models were used to assess whether the modality of reprocessing impacted image and video quality. For clinical testing, mixed linear models showed minimal quantitative differences in linear analog score (P= .04; estimated change, 3.12; scale, 0-100) and overall image quality value (P= .007; estimated change,-0.12; scale, 1-5) favoring ETO but not for rank value (P= .06). On phantom testing, maximum depth of penetration was lower for ETO endoscopes (P < .001; change in depth, 0.49 cm). In this prospective study, expert review and phantom-based testing demonstrated minimal differences in image quality between echoendoscopes reprocessed using HLD vs ETO+ HLD over 2 years of clinical use. Further studies are warranted to assess the long-term clinical impact of these findings. In the interim, these results support use of ETO sterilization of EUS instruments if deemed clinically necessary.

Evaluation of ethylene oxide, gamma radiation, dry heat and autoclave sterilization processes on extracellular matrix of biomaterial dental scaffolds

Scaffolds used to receive stem cells are a promising perspective of tissue regeneration research, and one of the most effective solutions to rebuild organs. In the near future will be possible to reconstruct a natural tooth using stems cells, but to avoid an immune-defensive response, sterilize the scaffold is not only desired, but also essential to be successful. A study confirmed stem cells extracted from rat’s natural teeth, and implanted into the alveolar bone, could differentiate themselves in dental cells, but the scaffold’s chemistry, geometry, density, morphology, adherence, biocompatibility and mechanical properties remained an issue. This study intended to produce a completely sterilized dental scaffold with preserved extracellular matrix. Fifty-one samples were collected, kept in formaldehyde, submitted to partial demineralization and decellularization processes and sterilized using four different methods: dry heating; autoclave; ethylene-oxide and gamma-radiation. They were characterized through optical images, micro-hardness, XRD, EDS, XRF, SEM, histology and sterility test. The results evidenced the four sterilization methods were fully effective with preservation of ECM molecular arrangements, variation on chemical composition (proportion of Ca/P) was compatible with Ca/P proportional variation between enamel and dentine regions. Gamma irradiation and ethylene oxide presents excellent results, but their viability are compromised by the costs and technology’s accessibility (requires very expensive equipment and/or consumables). Excepted gamma irradiation, all the sterilization methods more than sterilizing also reduced the remaining pulp. Autoclave presents easy equipment accessibility, lower cost consumables, higher reduction of remaining pulp and complete sterilization, reason why was considered the most promising technique.

Mechanisms Affecting Physical Aging and Swelling by Blending an Amphiphilic Component.

Polymer blending is a promising method to overcome stability obstacles induced by physical aging and swelling of implant scaffolds prepared from amorphous polymers in biomedical application, since it will not bring potential toxicity compared with chemical modification. However, the mechanism of polymer blending still remains unclearly explained in existing studies that fail to provide theoretical references in material R&D processes for stability improvement of the scaffold during ethylene oxide (EtO) sterilization, long-term storage, and clinical application. In this study, amphiphilic poly(ethylene glycol)-co-poly(lactic acid) (PELA) was blended with amorphous poly(lactic-co-glycolic acid) (PLGA) because of its good miscibility so as to adjust the glass transition temperature (Tg) and hydrophilicity of electrospun PLGA membranes. By characterizing the morphological stability and mechanical performance, the chain movement and the glass transition behavior of the polymer during the physical aging and swelling process were studied. This study revealed the modification mechanism of polymer blending at the molecular chain level, which will contribute to stability improvement and performance adjustment of implant scaffolds in biomedical application.

The effect of Gamma and Ethylene Oxide Sterilization on a Selection of Active Pharmaceutical Ingredients for Ophthalmics

Ensuring the sterility of life science products plays a pivotal role in the healthcare sector. Gamma irradiation and ethylene oxide sterilization are two commonly applied methods for the sterilization of medical devices, packaging components and Active Pharmaceutical Ingredients (API) for medicinal products. Focussed studies on the effects of sterilization processes on APIs remain limited. In this research study, five APIs, frequently used in sterile ophthalmic preparations were subjected to both gamma irradiation and ethylene oxide under different process conditions. The following APIs of GMP quality were selected: dexamethasone, aciclovir, tetracycline hydrochloride, triamcinolone and methylprednisolone. Analyses were performed using High Performance Liquid Chromatography equipped with UV detection and the effect of sterilization conditions on the APIs was evaluated by the assay and related substances test prescribed by the European Pharmacopoeia (Ph. Eur.). It was concluded that exposure to ethylene oxide resulted in compliance with Ph. Eur. for all APIs. While dexamethasone and methylprednisolone did not meet the requirement for the Ph. Eur. after exposure to gamma irradiation, the other three APIs did meet the requirement under the specified irradiation conditions. Subsequent optimization of sterilization parameters positively influenced the compliance to the Ph. Eur. requirements.

Dimensional accuracy of 3D printing navigation templates of chemical-based sterilisation

3D printed navigational templates have facilitated the accurate treatment of orthopaedic patients. However, during practical operation, it is found that the location hole occasionally deviates from the ideal channel. As such, there will be a security risk in clinical applications. The purpose of this study was to evaluate the influence of chemical-based sterilisation methods on the dimensional accuracy of different materials and the influence of module parameters on the degree of deformation. We found that polylactic (PLA) modules sterilised with ethylene oxide (EO) would undergo micro-deformation, and these micro-deformation characteristics depend on the building direction, i.e., the module stretches in the Z direction and shrinks in the X and Y directions. Heat-resisting polylactide (HR-PLA) has the same melting temperature (Tm) as PLA, but its glass transition temperature (Tg) is greater than the EO sterilisation temperature, so there is no obvious deformation after EO sterilisation. The layer height of the module were inversely proportional to the degree of deformation in the same sterilisation method. The deformation time of the module is concentrated within 2 h after heating. The micro-deformation of the 3D printing module depends on its Tg, sterilisation temperature, and duration of the sterilisation cycle.