Effect Of Gamma Sterilization Research Articles

A comprehensive review on recent nanosystems for enhancing antifungal activity of fenticonazole nitrate from different routes of administration

This review aims to comprehensively highlight the recent nanosystems enclosing Fenticonazole nitrate (FTN) and to compare between them regarding preparation techniques, studied factors and responses. Moreover, the optimum formulae were compared in terms of in vitro, ex vivo and in vivo studies in order to detect the best formula. FTN is a potent antifungal imidazole compound that had been used for treatment of many dangerous fungal infections affecting eye, skin or vagina. FTN had been incorporated in various innovative nanosystems in the recent years in order to achieve significant recovery such as olaminosomes, novasomes, cerosomes, terpesomes and trans-novasomes. These nanosystems were formulated by various techniques (ethanol injection or thin film hydration) utilizing different statistical designs (Box-Behnken, central composite, full factorial and D-optimal). Different factors were studied in each nanosystem regarding its composition as surfactant concentrations, surfactant type, amount of oleic acid, cholesterol, oleylamine, ceramide, sodium deoxycholate, terpene concentration and ethanol concentration. Numerous responses were studied such as percent entrapment efficiency (EE%), particle size (PS), poly-dispersity index (PDI), zeta potential (ZP), and in vitro drug release. Selection of the optimum formula was based on numerical optimization accomplished by Design-Expert® software taking in consideration the largest EE %, ZP (as absolute value) and in vitro drug release and lowest PS and PDI. In vitro comparisons were done employing different techniques such as Transmission electron microscopy, pH determination, effect of gamma sterilization, elasticity evaluation and docking study. In addition to, ex vivo permeation, in vivo irritancy test, histopathological, antifungal activity and Kinetic study.

Corneal targeted fenticonazole nitrate-loaded novasomes for the management of ocular candidiasis: Preparation, in vitro characterization, ex vivo and in vivo assessments

The purpose of this manuscript was to develop and optimize Fenticonazole Nitrate (FTN)-loaded novasomes aiming to enhance drug corneal penetration and to improve its antifungal activity. Ethanol injection was used to formulate FTN-loaded novasomes adopting a central composite design. The researched factors were: stearic acid concentration (g%) (A), span 80: drug ratio (B) and cholesterol amount (mg) (C), and their effects on percent entrapment efficiency (EE%), particle size (PS), poly-dispersity index (PDI), zeta potential (ZP), and in vitro drug release after 8 hours (Q8h) were studied. Numerical optimization by Design-Expert® software was employed to select the optimum formula in respect to highest EE%, ZP (as absolute value), and Q8h >80% and lowest PS and PDI. Additional evaluation of the optimum formula was accomplished by short term stability study, effect of gamma sterilization, determination of Minimal Inhibitory Concentration and ex vivo corneal permeation study. The in vivo evaluation of the optimum formula was done to ensure its safety via in vivo ocular irritancy and in vivo corneal tolerance studies. Also, the efficacy was confirmed through in vivo corneal uptake study and susceptibility test. The optimum formula with the highest desirability value (0.738) showed EE% (94.31%), PS (197.05 nm), ZP (-66.95 mV) and Q8h (85.33%). It revealed to be safe, with augmented corneal permeation (527.98 µg/cm2) that leads to higher antifungal activity. The above results confirmed the validity of novasomes to improve the corneal permeation and antifungal activity of Fenticonazole Nitrate.

Effect of gamma sterilization on Gymnema sylvestre leaf extract fused Polycaprolactone nanofiber for effective wound dressing applications

Nanomaterials have been proven to speed up wound healing compared to other wound healing materials. In the present study, Gymnema sylvestre leaf extract was incorporated into polycaprolactone (PCL) nanofiber, gamma sterilized and used for efficient wound dressing applications. The synthesized nanofibers (NFs) were beadless, hydrophilic, and continuous, exhibited surface mediated antibacterial activity against wound pathogens and enhanced proliferation of fibroblast cells. The fabricated NFs can be constructively used for wound care application.

Effect of gamma sterilization on the properties of microneedle array transdermal patch system

Soluble microneedles (MNs) of four different hydrophilic polymers namely sodium carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP) K30, PVP K90 and sodium hyaluronate (HU) were fabricated by mold casting technique. When exposed to gamma radiation, a dose of 25 kilogray (kGy) was found to render the microneedle (MN) sterile. However, CMC was found to form MNs with poor mechanical properties, whereas PVP K30 MNs were drastically deformed upon exposure to applied dose as observed in bright field microscopy. Scanning electron microscopy (SEM) revealed that morphology of PVP K90 and HU MNs were not significantly affected at the applied dose. The appearances of characteristic peaks of irradiated MNs of PVP K90 and HU in Fourier-transform infrared spectra suggested structural integrity of the polymers on irradiation. Differential scanning calorimetry (DSC) indicated gamma irradiation failed to alter the glass transition temperature and thus mechanical properties of PVP K90 MNs. However, DSC and Powder X-ray Diffraction (PXRD) conclusively indicated that the degree in crystallinity of HU was substantially reduced on irradiation. In vitro dissolution profiles of sterile PVP K90 and HU MNs were similar to un-irradiated MNs with a similarity factor (f2) of 64 and 54, respectively. In vivo dissolution studies in human subjects indicated that sterile MNs of PVP K90 and HU exhibited dissolution of 78.45 ± 1.09 and 78.57 ± 0.70%, respectively, after 20 min. The studies suggested that PVP K90 and HU could be suitable polymers to fabricate soluble MNs as the structural, morphological, microstructural and dissolution properties remained unaltered post γ sterilization.

Effect of Formulation Variables and Gamma Sterilization on Transcorneal Permeation and Stability of Proniosomal Gels as Ocular Platforms for Antiglaucomal Drug.

This study aims to evaluate the effect of different formulation variables (surfactant type and HLB value) adopting full factorial design (51. 21) using coacervation phase technique on in vitro characterization of dorzolamide hydrochloride (DZ)-loaded proniosomal gels, namely, entrapment efficiency percentage (EE%), vesicle size distribution, polydispersion index (PDI), and in vitro DZ release. The optimum formula F2 with a desirability value of 0.937 composed of 40mg DZ, 500mg span 60, 500mg of L-α-Lethicin, and 55.5mg cholesterol showing EE% of 84.5 ± 1.5%, PS of 189.5 ± 35.76nm with PDI 0.8 ± 0.28 and 58.51% ± 1.00 of DZ released after 8h was further evaluated using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The effect of gamma sterilization on transcorneal permeation and stability of DZ from the selected formulation (F2) revealed that F2 was significantly tolerable, stable, and competent to corneal permeation confirmed by histological examination, confocal laser microscopy, and intraocular pressure (IOP) measurement. Significant corneal bioavailability was attained from formula F2 (370.6mg. h/m) compared to the market product Trusopt® eye drops (92.59mg. h/ml) following IOP measurement, thereby proniosomal gels could be considered as tolerable and competent ocular platforms for improving the transcorneal permeation of DZ.

Effects of gamma sterilization on the physicomechanical and thermal properties of gelatin‐based novel hydrogels

Hydrogels are attracting ample attention for tissue engineering application thanks to their water‐loving attribute and closely mimicry to the natural extracellular matrix. However, effectively and efficiently sterilization of hydrogels without compromising their end‐use beneficial attributes is a major challenge. The aim of this work is to study the resistance to gamma sterilization of newly developed gelatin‐based hybrid hydrogels for tissue engineering. This study reported the investigation of 25 kGy gamma sterilization, a typical sterilization procedure for healthcare products, on the physicomechanical and thermal properties of a three set of gelatin‐based novel hydrogels, namely, gelatin–polyethylene glycol (G/PEG), G–PEG–hydroxyethyl cellulose (G/PEG/HEC), and G–PEG–chitosan (G/PEG/CH). Fourier transform infrared and thermogravimetric analysis were done to evaluate the chemical change and variation of thermal behavior, respectively, imposed by the gamma exposure, and the results showed that gamma sterilization did not modify the chemical composition and thermal degradation behavior of the hydrogels. The water uptake, mechanical properties (both in tension and compression), and stress relaxation experiments revealed that parent G/PEG and interpenetrating polymer network (IPN) G/PEG/CH were nearly negligibly sensitive to the gamma sterilization. However, semi‐IPN G/PEG/HEC appeared to be slightly vulnerable to the gamma exposure: a decrease in modulus and strength but simultaneous increase in water uptake, percentage dissipation energy, and stress relaxation responses were observed. POLYM. ENG. SCI., 59:2533–2540, 2019. © 2019 Society of Plastics Engineers

TO EVALUATE THE QUALITY OF CRYOPRESERVED GAMMA-STERILIZED DOG SKULL AT TISSUE CRYOPRESERVATION UNIT - HUE UNIVERSITY OF MEDICINE AND PHARMACY HOSPITAL

Objective: To evaluate the effect of gamma sterilization and the changes in the durability and the histological structure of cryopreserved gamma-sterilized dog skull. Subjects and methods: 50 dog skull fragments had the same size (4 x 4 cm), which were taken at parieto-frontal region, symmetrically through the midline of the skull were divided into two lots. Evident lot consisting of 50 fragments were just cryopreserved, not irradiated by gamma rays. Experimental lot which composed of 50 fragments were cryopreserved and exposed to 25 kGy of gamma radiation. Afterwards, evaluating the changes in the durability, microscopic structure and the effectiveness of sterilization on the dog skull after being cryopreserved at -85 0C in 3 months and exposed a gamma sterilization. Results: The durability was decreased of 8.28% compared with the lot of dog skull just cryopreserved at -85 0C and not exposed a gamma sterilization. On histological structure, no difference was found between the two lots and there was no structural change in the irradiated dog skull. All gamma-sterilized dog skull fragments were negative with bacteria culture test. The gamma ray had the ability to kill bacteria completely in the type of bacteria commonly infected tissue. Conclusion: After being cryopreserved at -85 0C in 3 months and exposed a gamma sterilization dose of 25 KGy, the durability of dog skull was insignificantly decreased and the microscopic structure was not changed. All irradiated dog skull fragments were negative with bacteria culture test. Key words: dog skull, gamma, durability, irradiated

Sorption of radiostrontium on various soils

The adsorption kinetics of 85Sr onto three pedologically characterized mineral soils was investigated, namely, one soil from the Chernobyl-Exclusion zone, Ukraine (CEZ-soil), one soil from the dismantling site of a former nuclear research reactor in Germany (DRE-soil) and a sandy reference soil (RefeSol-04A) from the Fraunhofer IME system, Germany. After seven days of treatment with 85Sr on an overhead shaker, Sr-sorption reached a (temporal) steady state. This timeframe was consistent for all three soils and independent of soil characteristics. From this experiment, maximum Kd values were calculated and compared with the existing literature. They agreed well with predictions made by the co-criterion concept for Kd(Sr) proposed by IAEA. Furthermore, the effect of gamma-sterilization and the consistency of Kd values in soils over longer periods of time is discussed.

THE EFFECT OF GAMMA STERILIZATION AND ITS EFFECT ON MICROSCOPIC STRUCTURE OF DEEP FROZEN DOG SKULL

Objective: To evaluate the effect of gamma sterilization and its effect on microscopic structure of deeply frozen dog skull. Subjects and methods: 50 pairs of dog skull fragments have the same size,which were taken symmetrically through the midline of the skull, were divided into two lots. Evident lot consisting of 50 pieces are just deeply frozen, not irradicated. Experimental lot which was composed of 50 pieces were deeply frozen and exposed to 25kGy of gamma radiation. Afterwards, to evaluate the effect of gamma sterilization and compare the alter of bone matrix between lot groups. Results: After gamma irradiation, all dog skull fragments were negative with bacteriological examination. In microscopic scale, no difference was found between the two lots and there was no structural change in the irradiated fragments of all dog skull. Conclusion: Gamma irradiation with 25 kGy: (i) It has the ability to kill bacteria completely in the type of bacteria commonly infected tissue. (ii) It does not alter the structure of dog skull in microstructures. Key words: dog skull, gamma, sterilize

Assessment of γ-sterilization and/or cross linking effects on orthopedic biomaterial using optical diffuse reflectance spectroscopy

The effects of gamma sterilization and/or cross linking on the band gap properties of ultra-high molecular weight polyethylene (UHMWPE) were studied with diffuse reflectance spectroscopy (DRS). Sheets of UHMWPE were prepared and irradiated for total dose values of 25kGy, 50kGy, 100kGy, and 150kGy, respectively. After irradiation, samples were tested for reflectance measurements over the wavelength range of 200nm to 1200nm. Kubleka-Munk function obtained from each measurement was then used to extract the band gap properties of each sample. The properties included were: Urbach energy (Eu), direct and indirect energy band gaps and number of atoms in CC unsaturation and/or conjugation. The results revealed that Urbach energy (Eu) had linear correlation with absorbed dose having goodness of fit, slope, and intercept values of 94%, 0.70, and 156 meV, respectively. In addition to this, linear decrease and dependence of CC unsaturation and/or conjugation on direct energy band gaps and absorbed dose were also evident. This behavior was attributed to radiation induced structural damage and alterations which included both chemical and physical alterations.

Hemocompatibility and surface properties of bovine pericardial patches: Effects of gamma sterilization

In the present study, the effects of sterilization by gamma irradiation on hemocompatibility and surface properties of the acellular bovine pericardium, a versatile biomaterial were investigated. The native bovine pericardium was decellularized using SDS for one group, Triton-X 100 for other group and subsequently sterilized with gamma rays. The chemical composition was confirmed using infrared spectroscopy, morphological changes by scanning electron microscopy and in vitro hemo-compatibility studies were conducted. Our results indicated that gamma ray sterilization process had significant effects on the processed bovine pericardium. A confirmed decrease in hemocompatibiity, with changes in the collagen organization and fragmentation was noticed. Conventional sterilization methods are not suitable for the targeted biomaterial since the proteins in biomaterial get denatured, compromise their physicochemical properties and hemocompatibiity.

Effect of gamma sterilization on microhardness of the cortical bone tissue of bovine femur in presence of N-Acetyl-L-Cysteine free radical scavenger

Gamma sterilization is usually used to minimize the risk of infection transmission through bone allografts. However, it is believed that gamma irradiation affects the mechanical properties of allografts and free radical scavengers can be used to alleviate the radiation-induced degradation of these properties. The aim of this study was to investigate the radioprotective effects of N-Acetyl-L-Cysteine (NAC) free radical scavenger on the material properties of sterilized bovine cortical bone at microstructure level. Forty-two cortical tissue specimens were excised from three bovine femurs and irradiated to 35 and 70 kGy gamma rays in the presence of 5, 50, and 100 mM concentrations of NAC. The localized variations in microhardness were evaluated via indentation in the radial and longitudinal directions to examine different regions of the microstructures of the specimens, including the osteonal and interstitial tissues. A significant increase was observed in the hardness of osteonal, interstitial, and longitudinal combined microstructures exposed to 35 and 70 kGy radiations (P < 0.05), whereas a relative reduction of the hardness was observed in the radial direction. Furthermore, it was found that the application of 50 and 100 mM NAC during gamma irradiation significantly subsided the hardening in longitudinal combined microstructure. Moreover, the reduction of hardness in radial direction was suppressed in the presence of 100 mM of NAC. In conclusion, the results indicated that NAC free radical scavenger can protect the cortical bone against deteriorative effects of ionizing radiation and can be used to improve the material properties of sterilized allografts.

The Effect of Gamma Sterilization on the Insecticidal Toxicity of Engineered and Conventional &lt;I&gt;Bacillus thuringiensis&lt;/I&gt; Strains

This study evaluates the effect of gamma radiation on the spore activity, toxicity, and crystal structures of two engineered Bacillus thuringiensis (Bt) strains, TnX and TnY, and the reference Bt strain HD-1. We attempted to identify dosages of cobalt-60 gamma radiation that would inactivate Bt spores but not affect its toxicity. In the radiation dosage range of 10-15 kilogray, no viable spore formation and no significant reduction of the efficiency of Bt against lepidopteran larvae were observed. However, further sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results show that the components of the protoxin are affected by gamma radiation and that some bands are absent after treatment compared with the controls; the change in the protoxin band pattern depends on the type of Bt strain. Furthermore, the spore crystal structure of three Bt strains was studied with scanning electron microscopy and transmission electron microscopy. The results show that there are no changes in the size or shape of the treated Bt spores and crystals compared with the controls. The use of gamma radiation is effective to inactivate the spores of engineered Bt strains while preserving stable Bt toxicity against the target insect larvae.

Impact of Biomechanical Forces on Antibiotics Release Kinetics from Hydroxyapatite Coated Surgical Fixation Pins

This work investigates the impact of biomechanical wear and abrasion on the antibiotic release profiles of hydroxyapatite (HA) coated fixation pins during their insertion into synthetic bone. Stainless steel fixation pins are coated with crystalline TiO2 by cathodic arc evaporation forming the bioactive layer for biomimetic deposition of Tobramycin containing HA. Tobramycin is either introduced by co-precipitation during HA formation or by adsorption-loading after HA deposition. The samples containing antibiotics are inserted into bone mimicking polyethylene foam after which the drug release is monitored using high performance liquid chromatography. This analysis shows that HA coating wear and delamination significantly decrease the amount of drug released during initial burst, but only marginally influence the sustained release period. Spalled coating fragments are found to remain within the synthetic bone material structure. The presence of HA within this structure supports the assumption that the local release of Tobramycin is not only expected to eliminate bacteria growth directly at the pin interface but as well at some distance from the implant. Furthermore, no negative effect of gamma sterilization could be observed on the drug release profile. Overall, the observed results demonstrate the feasibility of a multifunctional implant coating that is simultaneously able to locally deliver clinically relevant doses of antibiotics and an HA coating capable of promoting osteoconduction. This is a potentially promising step toward orthopaedic devices that combine good fixation with the ability to treat and prevent post-surgical infections.

Influence of screw holes and gamma sterilization on properties of phosphate glass fiber-reinforced composite bone plates

Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. For a material that degrades, the main advantage is that an implant would not necessitate a second surgical event for removal. In this study, fibers produced from a quaternary phosphate-based glass (PBG) in the system 50P2O5-40CaO-5Na2O-5Fe2O3 were used to reinforce PLA polymer. The purpose of this study was to assess the effect of screw holes in a range of PBG-reinforced PLA composites with varying fiber layup and volume fraction. The flexural properties obtained showed that the strength and modulus values increased with increasing fiber volume fraction; from 96 MPa to 320 MPa for strength and between 4 GPa and 24 GPa for modulus. Furthermore, utilizing a larger number of thinner unidirectional (UD) fiber prepreg layers provided a significant increase in mechanical properties, which was attributed to enhanced wet out and thus better fiber dispersion during production. The effect of gamma sterilization via flexural tests showed no statistically significant difference between the sterilized and nonsterilized samples, with the exception of the modulus values for samples with screw holes. Degradation profiles revealed that samples with screw holes degraded faster than those without screw holes due to an increased surface area for the plates with screw holes in PBS up to 30 days. Scanning electron microscope (SEM) analysis revealed fiber pullout before and after degradation. Compared with various fiber impregnation samples, with 25% volume fraction, 8 thinner unidirectional prepreg stacked samples had the shortest fiber pull-out lengths in comparison to the other samples investigated.

Effects of gamma-sterilization on the physico-chemical properties of natural sediments

Batch U(VI) sorption/reduction experiments were completed on sterilized and non-sterilized sediment samples to elucidate biological and geochemical reduction mechanisms. Results from X-ray absorption near-edge structure (XANES) spectroscopy revealed that γ-sterilized sediments were actually better sorbents of U(VI), despite the absence of any measurable biological activity. These results indicate that γ-irradiation induced significant physico-chemical changes in the sediment which is contrary to numerous other studies identifying γ-sterilization as an effective and minimally invasive technique. To identify the extent and method of alteration of the soil as a result of γ-sterilization, untreated soil samples, physically separated size fractions, and chemically extracted fractions of the soil were analyzed pre- and post-sterilization. The effects of sterilization on mineralogy, pH, natural organic matter (NOM), cation exchange capacity (CEC), and iron oxidation state were determined. Results indicated that major mineralogy of the clay and whole sediment samples was unchanged. Sediment pH decreased only slightly with γ-irradiation; however, irradiation produced a significant decrease in CEC of the untreated sediments and affected both the organic and inorganic fractions. Mössbauer spectra of non-sterile and γ-sterilized sediments measured more reduced iron present in γ-sterilized sediments compared to non-sterile samples. Our results suggest that sterilization by γ-irradiation induced iron reduction that may have increased the sorption and/or reduction of U(VI) onto these sediments. However, Mössbauer and batch sorption data are somewhat contradictory, the former indicates that the iron oxide or iron hydroxide minerals are more significantly reduced while the later indicates that reduced clay minerals account for greater sorption of U(VI).

77. Effect of gamma sterilization on proteins in AlloDerm TM regenerative tissue matrix

77. Effect of gamma sterilization on proteins in AlloDerm TM regenerative tissue matrix

Fabrication of poly(propylene fumarate)-based orthopaedic implants by photo-crosslinking through transparent silicone molds

This work presents a new molding process for photo-crosslinked, degradable polymeric networks of poly(propylene fumarate) (PPF) and the crosslinking agent poly(propylene fumarate)-diacrylate (PPF-DA). Transparent room temperature vulcanizing silicone molds were fabricated for parts ranging from simple test coupons to orthopaedic implants. The PPF/PPF-DA resin blend was injected into the cavity and photo-crosslinked as light was transmitted through the mold wall. The volumetric shrinkage, mechanical properties, and the effects of gamma sterilization were reported for molded PPF/PPF-DA networks prepared with varying compositions of the two polymer components. The shrinkage decreased while the mechanical properties displayed a general increasing trend when more of the crosslinking agent was incorporated into the network. Gamma irradiation resulted in an improvement of the mechanical properties. In addition, PPF/PPF-DA replicates of a 70:30 poly( l/ dl-lactide) biodegradable fixation plate and a bone allograft interbody fusion spacer were produced to evaluate the performance of PPF/PPF-DA as an orthopaedic implant and allow for a comparison to be made with materials that have been established for clinical use.

Effects of gamma-sterilization on butyltin homogeneity and content in sediments: a GC-ICP-MS study.

A GC-ICP-MS method based on extraction and alkylation of butyltins with sodium tetraethylborate was used to quantitatively assess the fate of these analytes in solutions and sediments following exposure to gamma-irradiation. The effects of a 2.5 Mrad sterilization dose on three butyltin species in both methanolic calibration solutions and in sediment matrices were investigated. Although significant losses of tributyltin (TBT, 90%), dibutyltin (DBT, 100%) and monobutyltin (MBT, 80%) were detected in standard solutions prepared in methanol following gamma-irradiation, no species inter-conversion occurred. Some degradation of TBT (38%) and DBT (32%) but no significant change in MBT content was found using a spiked sediment CRM HISS-1. Conversion DBT to MBT in spiked HISS-1 was deduced. Much smaller degradation of TBT (16% loss) and 10% loss of DBT by conversion to MBT (14% gain) was registered using a sediment blend of PACS-2 and HISS-1 (SOPH). Despite some initial losses of TBT and DBT due to irradiation, better than 2% RSD in both TBT and DBT concentrations measured in twelve different bottles of blended sediment SOPH were obtained, indicating the material may be considered homogeneous for these analytes. Results from a long-term five-year stability study of PACS-2 show that all three butyltins are stable during storage at 4 degrees C followed with 2.5 Mrad minimum dose of gamma-irradiation sterilization treatment.