Solving the consumable problem
Nitritex, global supplier of BioClean cleanroom consumables, has developed a solution to the problem of contamination caused by reusable goggles in sterile suites and has also invested in new technology in glove manufacturing in response to demand for cleaner and safer gloves
The use of goggles in sterile suites has increased in the past few years as the risk of product contamination has become a recognised and major issue. Protection of staff from the potential harmful effects of certain drugs and chemicals is the other important factor leading to the use of goggles. If we take the view that all products entering a sterile suite must be sterile, there is a problem with goggles. Discussion with many users of goggles has led us to the conclusion that most goggles are not actually sterilised. While they are, in general, either sanitised or disinfected, the real problem is that to be sure of sterilisation the goggles must be totally immersed for an extended period to ensure that the sanitising medium reaches all parts of the goggles. In our research, this was not happening. There are, however, major problems associated with sterilisation of goggles either by gamma sterilisation, steam (autoclave) or ethylene oxide gas. In all these types of sterilisation, there is significant degradation of the plastics used in the goggles. This dramatically reduces the useful life of the goggles and increases their cost in use. Gamma sterilisation also results in fogging of the lens and early disposal. In the case of ethylene oxide sterilisation, there is the additional problem of residuals that may build up over time and become a contamination risk. Our research indicates that most goggle users, therefore, do not use these three methods to sterilise their goggles between each use. Instead their goggles are subjected to a range of 'sanitising' or 'disinfection' treatments that include bleach, ethanol, IPA sprays and IPA saturated wipes. In the majority of users surveyed, (see Table 1) the goggles were 'treated' after use and again before the next use. After treatment, however, there appeared to be no SOP in place for packing and storing the goggles between each use. Significantly, in no case surveyed was a protocol found that allowed for periodic washing of the goggles to remove skin debris, particulates and any other residues, nor was there any testing of the goggles for levels of residuals. This leads to an increased risk of product contamination over time. A survey of the goggles available found that there are a number of goggles available that claim to be resistant to gamma or ethylene oxide sterilisation. On closer examination, however, none of these goggles offered long term use without degradation. Typically, gamma irradiated goggles lasted between four and eight irradiation cycles (at 25 kGray minimum dosage) before disposal was necessary. Ethylene oxide goggles were seen to last longer, but there were wide variances in useful life. This was probably reflective of the different sterilisation cycles being used. Given that there are clearly many negatives associated with the use of goggles in sterile environments, it is not surprising that regulatory authorities in certain countries have 'advised' users to seek alternatives to goggles to ensure that only sterile products enter the cleanroom environment. While it is possible to buy single use sterile goggles, for most users the cost is prohibitive.
The solution Where goggles are used, coverage for the rest of the face to prevent product contamination will usually be achieved by the use of a disposable sterile cleanroom facemask. BioClean 100 3 ply sterile cleanroom facemasks are designed to repel liquids on the outer facing layer and to absorb moisture on the inner layer to prevent skin irritation. The middle filter layer prevents sub-micron particulate contamination from passing in either direction. Nitritex has now combined its BioClean 100 sterile cleanroom facemask with an attached 'optically correct' 3M acrylic visor. The BioClean Clearview range comprises tie-on and headloop/earloop variants, all in 210mm width. The major advantages of BioClean Clearview cleanroom facemasks are: a) single use (no degradation issue) b) sterile (suitable for entry to sterile suites) c) three methods of attachment (to suit all user requirements) d) optically correct visor (will not cause viewing distortion)
Trials of the BioClean Clearview facemasks have proven that they offer a viable alternative to goggles in sterile environments. Commenting on the trials, Nitritex European sales director Richard Bryant says: "It has taken a lot of research and development work to reach the stage where we have the right range of sterile visor facemasks. I am now confident that the BioClean Clearview range is the answer to the problem." Glove technology The use of gloves manufactured from natural latex has increased dramatically over the past 15 years. As a result it has been estimated that up to 30% of the UK population has atopic allergy and 43% some sort of skin irritation. Within these groups a latex sensitivity of 10% has been observed, indicating that 3% or 1.5 million people in the UK are at risk (Turner; Occupational Health 1997; 49:2, 57-60). An allergic reaction to latex proteins (Type I) is typified by an almost immediate hypersensitivity and results in anaphylaxis (hypertension, rash and bronchospasm). More frequently seen though, are Type IV reactions, which can be described as an immune response to chemical allergens, such as chemical accelerators used in the glove manufacturing process. These accelerators are present in the vast majority of disposable gloves in use today, including those manufactured from latex, vinyl and nitrile. These manifest themselves as skin reactions, erythemia blisters, constant itching and broken skin and chronic rhinitis. While substantial efforts have been made in reducing the level of proteins and accelerators in disposable latex, nitrile and vinyl gloves, it has not been possible to totally eliminate them. As a result allergies occur frequently. This is particularly relevant for staff working in controlled and critical environments, many of which are wearing gloves for extended periods. For a number of years research has been focused on alternative polymer materials that have the ability to be manufactured into gloves using an aqueous-based environmentally friendly process with the following key attributes: 1. Free of latex proteins 2. Accelerator free 3. Strength and elasticity 4. Wearer comfort 5. Environmentally friendly
Allergy solution In the US, Dow Chemical was researching this area in the late 1990s and developed an alternative material, polyurethane (PU), which has been developed for use on standard glove production lines, utilising an aqueous-based delivery system. The advantages of this new material (now called Intacta) are that it can be used for manufacturing gloves without the addition of accelerators, is 100% latex free and, in the context of cleanroom use, the gloves produced are extremely low in particulates (see Table 2), extractables (see Table 3) and demonstrate excellent ESD properties (see Table 4). They also exhibit industry-leading low levels of out-gassing. Gloves manufactured with the Intacta PU have excellent strength (similar to nitrile) and elasticity (similar to latex) and have no odour, attributes that all significantly enhance wearer comfort. With particle counts at <500 @ 0.5µm per cm2, these non-sterile gloves are already being used widely in the most critical environments in the microelectronics and semiconductor industry. The gloves are creating interest in the pharmaceutical and biotech markets. To maintain product quality, a e3.25m investment has been made in an ISO 14644-1 Class 4 (Class 10) cleanroom with full NEBB certification in Malaysia to process and pack the BioClean Intacta sterile and Intacta 4 and 5 non-sterile cleanroom gloves. Other BioClean gloves and consumables are also processed in this facility. Harry Kirk, sales & marketing director of Nitritex, says: "We have been in the cleanroom gloves business for more than 15 years and this is the single most important advance in cleanroom gloves during that time. Reaction from our distributors and end users has been incredible."
