Safety Assessment: Benzalkonium Chloride as Sanitising Agent

Safety Assessment: Benzalkonium Chloride as Sanitising Agent Benzalkonium Chloride Benzalkonium chloride or BAC is an antibacterial agent belonging to the quaternary ammonium compound group. It is widely used in the health care industry and cosmetic industry as an antimicrobial and cleansing agent. According to the Food and Drug Administration (FDA), 0.1-0.13% w/w BAC is considered safe and effective as an â€Å"antiseptic drug product†.55 BAC has also been recognized as safe and effective when incorporated into oral mouth rinses.56 BAC is also popularly used as a rinse-free hand sanitizer and for hand washing.57 Short-term and long-term clinical studies have shown that BAC incorporated in intranasal products is safe and well-tolerated. 58 Furthemore, BAC meets the performance criteria under the Tentative Final Monograph for Health Care Antiseptic Drug Products as an active component in rinse-free hand sanitizers. Sufficient evidence exists to support the usage of BAC as a Category I active ingredient in 1994. It was analyzed as a leave-on sanitizer at the Final Monograph for Healthcare Personnel Antiseptic Drug Products. 59 A study by Dyer et al concluded that a hand sanitizer with BAC as the main component was a safe and effective way of decreasing illness absenteeism in grade schools.60 The safety of BAC was reviewed by an expert panel and they concluded that at concentrations of up to 0.1%, free active ingredient is â€Å"safe for human use†.61 It was acknowledged that BAC can be used beyond being an active ingredient for leave-on products because of its safety and antimicrobial effectiveness profiles. The FDA has also agreed upon the usefulness of biocidal quaternary amino actives, particularly BAC, in their previous rulemaking. As an example, the FDA stated that â€Å"it was not seriously concerned with the safety of ‘quats’ for first aid uses like wound cleansers, skin wound protectants, and skin antiseptics† in the 1991 Proposed Rule for Topical Antiseptic Drug Products for Over-the-Counter Human Use; Tentative Final Monograph for First Aid Antiseptic Drug Products. BAC was found to meet the requirements for first-aid antiseptic applications as reviewed by the expert panel at that time. Furthermore, the FDA has permitted the combination of BAC and Benzethonium Chloride homologues at concentrations of up to 0.004% as a food preservative or for long-term ingestible applications.62 At the 2002 16th Report of the Cosmetic Ingredients Review Expert Panel, BAC was announced to be safe at concentrations of up to 0.1% w/w. The cosmetic applications studied here were those that encompassed a daily-use regimen. A publication was done on a cross-over study of 420 grade-school children (5-12 years old) for a period of 10 weeks. They were told to use a leave-on sanitizer with BAC as soon as they entered the classroom, before eating their snacks and lunch, after sneezing or coughing inside the classroom, and after using the restroom. They observed that even with frequent use, there was no adverse reaction such as edema, rash or erythema, among the students during or after the study.40 Another study published in 1998 investigated the performance of an alcohol-free hand sanitizer with BAC. They concluded that the product exceeded the minimum performance standards indicated by the FDA for reducing bacteria.63 BAC has been reported to be effective against a wide variety of microorganisms, such as mixed-type viruses and non-enveloped viruses. BAC even demonstrated on some instances, a significantly higher virucidal activity as compared to alcohol applications. One important aspect of BAC that should not be over-looked is its non-flammable nature. In fact, during the SARS epidemic in 2003, BAC-containing sanitizers were very effective against human coronavirus especially in use in airlines and airports as alcohol-containing products were banned because of issues in flammability. In a study on BAC at reducing illness in public and private schools, they observed a 44.2% decrease in incidence of gastrointestinal illnesses and a 50.2% reduction in respiratory-related illnesses. In a different double-blinded study with 769 students, there was a 33% reduction in illness-related absenteeism. It was recommended that alcohol-free leave-on sanitizers, like those with BAC, are the only appropriate composition for usage in settings as school. This is due to the possible misuse of alcohol-containing sanitizers as a fire accelerant or by intentional ingestion. An excellent review on the issue of bacterial resistance to antibacterial  sanitizers was also recently submitted by SDA to FDA in response to the reopening of the docket for comments. However, the FDA advised that further studies should be done regarding antimicrobial resistance and the potential development of resistance to these agents, including BAC. This was stated at the joint meeting in 1997 of the FDA Advisory Committees. In the field of Orthodontics, Othman et al 64 confirmed that adding BAC to an adhesive produces antibacterial properties. In the study, BAC was incorporated into a light-cured composite resin, and an evaluation of its antimicrobial and physical properties was done. BAC was incorporated into Reliance Phase II adhesive to produce BAC concentration from 0.25% to 2.50% wt/wt. The modified samples were cut into disks and incubated in Strep. mutans for two days. Amount of bacterial inhibition was measured with agar disk diffusion assay. Other disks were placed in brain-heart infusion medium with Strep. sobrinus to measure its adherence. Cells that adhered were measured. Tensile bond strength was analyzed using a universal testing machine by attaching traction hooks to bovine teeth with the modified adhesives. Results showed an increase in antimicrobial activity in composites with higher BAC. Antimicrobial activity was negative for the composites without BAC. The composite with BAC and with out BAC did not show any difference with regard to their diametral tensile stress and tensile bond strength. Therefore, they concluded that when BAC was combined with an orthodontic adhesive, it added antimicrobial properties without changing its mechanical properties. Another study that aimed to create an antibacterial adhesive without compromising its bond strength was done by Saito et al.65 Their aim was to find the dose of BAC that exhibited antibacterial effect and did not compromise bond strength. In Saito’s study, Superbond CB resin cement was used. A mixture of the polymer, monomer, catalyst and BAC was produced according to the instructions of the manufacturer. Composite disks with the following BAC concentration were produced: 0.25%, 0.75%, 1.25%, 1.75%, 2.5%, and 5% (wt/wt). Composite disks of the same size (0.8 mm x 2 .0 mm thickness) were made. The test bacteria used were Strep. mutans 10449 and PS14, and Strep. sobrinus 6715 and B13. A brain-heart infusion medium was used to grow the bacteria. To evaluate the antibacterial activity, disk diffusion assay was utilized. To analyze the release of BAC as shown by an inhibition of growth of the bacteria, the semidiameter of the growth inhibition zone was measured. The bacteria were grown overnight in a broth and diluted. An optical density of 0.5 (550nm) was used. An inoculation of 80  µL (60-fold dilution) was performed on the brain-heart infusion agar plates. A glass rod was used to spread the inoculums evenly providing uniform bacterial growth. The BAC-infused composite disks were placed on the agar and were incubated at 37 ºC. Two days after incubation, the inhibition zones were measured. Saito also tested the shear bond strength using 70 extracted human premolars. The teeth were randomly distributed into seven groups and embedded in acrylic except for the buccal areas which were used for bonding. The teeth were polished using rubber prophylactic cups with pumic for 10 seconds. The teeth were etched with 65% phosphoric acid for 30 seconds and washed for 20 seconds then orthodontic metal brackets were bonded. Composite with the following BAC concentrations were used to bond the brackets: 0%, 0.25%, 0.75%, 1.25%, 2.5%, and 5%. A 300-gram force was applied on each bracket (based on the study of Bishara et al66). The results were presented in standard deviation and mean and analyzed with ANOVA to determine if there were significant differences among the groups. For multiple comparisons, Fisher test was used. Statistical differences were detected by a Chi-square test. Significance was predetermined at P 0.5.38 Results showed that there were significant differences among the composites with different BAC concentrations. No significant differences were found among the bacterial strains. When placed on the agar plate with Strep. mutans or Strep. sobrinus, no inhibition zone was observed on the composite with 0% BAC. The composite disks with BAC demonstrated a significant antibacterial property when compared with the composite without BAC. The antibacterial effect was found to increase as BAC concentration increased. This was indicated by an increase in the bacterial inhibition zones that were measured. The disks with 5% BAC had the highest amount of antibacterial activity. A significant difference in bond strength was noted among the different composites with BAC. However, as BAC concentration was raised, they observed a decline in shear bond strength. The study of Saito et al concluded that adding BAC into composite resin attributes antimicrobial properties strong enough to inhibit Streptococcus mutans and Streptococcus sobrinus. A clinically acceptable range of shear bond strength is yet to be established scientifically. Saito noted that incorporation of BAC does not lessen the strength to less than 10 MPa when an etchant (phosphoric acid) is used. The range of shear bond strength in study was 10.12 MPa – 20.94 MPa. Saito et al further concluded that a composite incorporated with BAC â€Å"has a possibility for clinical application as a bonding adhesive†. It was recommended in the study that it is essential to acquire a long-term release behaviour of an antibacterial agent. Therefore, a study investigating the release behaviour of BAC should be done. It was mentioned in the study by Saito that BAC has been a popular choice of contact lens antiseptic. However, the quantity of BAC used in the study was less than the amount used in contact lenses. A typical bonding procedure in an orthodontic patient requires around 150 mg of composite adhesive. Therefore, 0.7 mg of BAC is required to achieve 0.5% BAC concentration. The same author in 2009 evaluated the antibacterial activity and cytotoxicity of an orthodontic adhesive containing BAC. To achieve the desired concentration of BAC, it was initially diluted to 50% by mixing it with the orthodontic polymer (wt/wt). It was diluted further with polymer to achieve the required concentration. 65 They achieved the following BAC concentrations: 0.25%, 0.75%. 1.25%, 1.75%, 2.5%, and 5.0% (wt/wt). Custom-made molds were used to produce BAC-composite disks of the same size (8.0 mm x 2.0 mm). The disks were evaluated using antibacterial and cytotoxicity assays with three independent runs. To perform the disk diffusion assay, the BAC composite disks were soaked in distilled water at 37 ºC for 0, 30, 90, and 180 days prior to the assessment of antibacterial activity. The test bacteria used were Strep. mutans 10449 and PS14 and Strep. sobrinus 6751 and B13. They were routinely grown in a brain-heart infusion medium for 24 hours. The growth inhibition of Strep. mutans and / or Strep. sobrinus showed the release of BAC into the agar medium. Electric digital callipers were used to take measurements of the zone of growth inhibition around each BAC composite disk. To test the cytotoxicity, human gingival fibroblast cultures were grown from the cells of healthy gingival tissues from patients who were undergoing extraction prior to orthodontic treatment. This was copied from the method of Somerman, et al. After the patients underwent extraction, a part of the gingival tissue attached to the interdental papilla was taken. The samples were washed twice in phosphate-buffered saline solution (PBS). The acquired tissues were dissected into 1-mm cubes and were transferred to 35-mm tissue culture dishes with ÃŽ ±-minimal essential medium supplemented with 100  µg/mL of penicillin G, 500  µg/mL gentamicin sulphate, 0.3  µg/mL amphotericin B, and 10% fetal bovine serum. Incubation of the cultures was done in a 37 ºC humidified incubator with 95% air and 5% carbon dioxide. When confluence was reached, the cells were detached using 0.05% trypsin in PBS for 10 minutes. They were subcultured in flasks and seeded.38 The controls used in the study were the resin disks without BAC. The harvested gingival cells were laid under resin disks. In between the disks and the gingival cells was an 8  µm PET membrane that allowed the passage of the components of the resins to make contact with the human gingival cells. This was based on the study of Tang et al. Incubation with the gingival cells were done at 37 ºC for 1, 3, and 6 days.38 A reduction assay kit containing tetrazolium bromide was used to assess the cytotoxicity. This was based on the reduction that occurs to MTT when exposed to living cell mitochondria. It becomes purple fromazan. After 1, 3, and 6 days, the cells were cleaned with PBS after removal of the resins and the medium. Addition of 0.5 mL MTT medium solution was made to the wells. The solution was incubated at 37 ºC for 3 hours. A microplate reader was used to measure the purplish lysate. They observed significant differences among the different lengths of time the samples were soaked in distilled water and among the BAC concentration. With the different bacteria, they did not detect any significant differences. No difference that was significant enough was also observed between the bacterial strain and BAC. There were significant differences noted regarding the antibacterial activity at 0 day between samples with 5% BAC compared to other BAC concentrations. There were also significant differences observed regarding antibacterial activity among 0.25%, 0.75%, and 1.25% BAC, and 1.75%, 2.5%, and 5% BAC concentration. However, there was not any significant difference detected among 1.75%. 2.5%, and 5% BAC concentrations. There was a significant difference at 180 days between 0.25%, 0.75%, and between 1.25% and 5% concentrations. They observed that the higher the concentration of BAC in the composite, the greater the decrease that occurred in antibacterial property based on the assay time prolongation. They concluded that when the samples were not soaked in water, they exhibited higher antibacterial activity. The resins with 5% BAC had the highest antibacterial property. There was a significant decrease in antibacterial activity after soaking the samples in water for 180 days at all BAC concentrations. The samples incorporated with 5% BAC had the highest antibacterial activity compared to the resin with 0.25% at all periods of the experiment. In fact, the antibacterial activity exhibited by the resin with 5% BAC soaked for 180 days was the same as the antibacterial activity shown by the resin containing 0.25% and 1.75% BAC prior to immersion in water. There were significant differences in MTT activity percentages among the BAC composites with regard to cytotoxicity to the human gingival cells. Saito’s study concluded that resins with 1.25% or 1.75% BAC exhibited constant antibacterial properties when immersed in water for 180 days due to the continuous BAC release. However, an increase in cytotoxicity was noted as the antibacterial activity increased. Therefore, composites with a higher concentration of BAC were shown to be more cytotoxic. A concentration of BAC that was 0.25% or 0.75% exhibited cytotoxicity similar to the resins without BAC or the controls at all test periods. Saito et al recommended that a similar study be made using saliva instead of water as the immersing medium. This is due to the presumption that the oral environment is different that it may influence the antibacterial activity and cytotoxicity of the resins with BAC. The study confirmed that adding BAC to a composite resin exhibits an antibacterial effect against Strep. mutans and Strep. sobrinus. The author suggested that BAC be tested in vivo for safety before it is tested clinically.

Beowulf - Pagan or Christian Epic? Essay -- Epic of Beowulf Essays

Beowulf Pagan or Christian Epic Beowulf: Pagan or Christian Epic? Although the story of Beowulf is filled with references to religion and faith, many discrepancies occur throughout the story that suggest that Beowulf is not a Christian epic. The character of Beowulf frequently speaks to God and obviously believes in His existence. However, pagan practices are mentioned in several places. Beowulf often refers to another being rather than the Christian God. Pagan practices of cremation and blood-drinking are included in the epic. There are also frequent allusions to the power of fate, the motive of blood revenge, and praise of worldly glory. All of these aspects make Beowulf a pagan tale with a few Christian elements. A key pagan reference in Beowulf is the entity Wyrd. â€Å"Now if Wyrd, Ruler of All, will permit, my stout sword will sing its greedy war-song....Wyrd always weaves as it must†. The Christian tradition clearly states the existence of only one supreme entity. It also states that anyone worshipping â€Å"false idols† is subject to punishment. If Beowulf was truly a Christian, he would not call to Wyrd for any type of assistance. One might argue that referring to Wyrd as â€Å"Ruler of All† suggests that this entity is the Christian God. But â€Å"God† is referred to throughout the epic. â€Å"For Grendel bore God’s anger...Mighty God rules mortals forever!†. These are two separate entities that serve different functions throughout the epic. A true Christian tale would not include any other â€Å"God† or all-powerful being rather than the one true God of the Christian teachings. The story also mentions that Hrothgar and his people mak e sacrifices to idols in an attempt to overcome the monster Grendel. â€Å"And so it came to pas... ... wealth. In conclusion, the epic tale of Beowulf is a pagan tale with a pagan hero. Although there are Christian images throughout the tale, the story is clearly pagan in nature. The Beowulf poet portrays the culture and people by separating the main ideas like a prism does with light. Although there are the Christian references surface throughout the tale, a look at the epic as a whole clearly shows its true pagan nature. No matter which end of the spectrum you are looking from, all the ideas prove that pagan concepts and principles prevail over the values of Christianity. It is shown on countless occasions through the material rewards, earthly fame, false idols, and burial practices. In the end, the separated lights in the prism come together and become one. This array of light in Beowulf is ultimately the strong presence of a pagan hero and a pagan culture.

How Bangladesh is affected by flooding

Flooding is a huge problem for the people in Bangladesh and the problems continue to have negative and positive effects on the people, property and land/environment. The negatives of flooding; There are many different types of floods that Bangladesh suffers from and these are; flash floods; where there is an extreme amount of rainfall effecting both upland areas and over time low land areas. This type of flood has a huge affect on property as it can wash it away completely destroying it and also flooding crops and killing them, this type of flooding will also deposit lots of sediment so the river bed will rise making the river easier to flood. River floods are where high amounts of rain and melted snow from the Himalayas completely flood the river and also the floodplain, the water can not be contained so flows over lands which is usually not protected, this again damages crops by flooding them and also ruining the land for future use as farm land. This type of flooding will also damage or even destroy property and in extreme cases entire settlements which in turn will also kill people if they do not evacuate quick enough. Rainwater floods are where there are again extreme amounts of rainfall and there is too much surface water and land is flooded. This can kill cattle, people and destroy farmland and crops which people need for their livelihoods. For example of crop destruction, in 1987 and 1988 rice production on a country scale was largely disrupted due to extreme floods. Even if engineering is successful and floods are controlled there is the negative effects that the country gets further into debt and a lot of the flood controls do not fit in with the natural environment so is an eye sore. Methods of flood control also effect farming in certain areas as they block irrigation of water so many farmers are complaining as they are not getting the water needed to grow crops for their livelihood. The worst effected areas of flooding are the coast as many people live here and this is where flooding is most extensive, many people are killed damage to property and farm land is huge so this disrupts the local economy. In the floods of 1991 flooding was that hard that waves were 7 metres high and this brought wind speeds of 225 km/h. people had to climb trees to evade the floods but over 150 000 people were drowned and 500 000 cattle were lost along with vast damage to settlements, electricity, roads and fishing. Deforestation is another big factor that is negative as this destroys trees that are vital for the world and also does not allow interception to occur so the snow melting from the Himalayas is coming directly to Bangladesh with nothing sopping it. As there is little knowledge and little communication available people can not prepare and are defenceless. With the vast amounts of chemicals and diseases in the Ganges, flooding just spreads this all around the country contaminating drinking water and brings huge problems that need huge amount of medical care so calls for the worlds charities to help. You can read also Waves There are very little positive effects of flooding as floods bring so much destruction. The positives though are; due to vast amounts of deposition the silt that is deposited is high in fertility so ‘repairs' the soil so can be used in the future making it good for crops to grow in. also the vast amounts of water, when controlled can be irrigated for the crops rice and jute which require a large amount of water to grow. This in turn helps re – boost the local economy and gets the farmers back to their usual livelihood. Finally in cases of extreme flooding where the world is made aware, it can show the kindness of countries by the help they donate and the medical care made available to help restore the country to normal. Although there will always be social, economic, and humane problems with flooding the key is for the country to recover as quick as possible with the least effects and damage done to the country and its people.

The book of Arts essays

The book of Arts essays The account of St.Paul's ill-fated journey to Rome in the New Testament's Book of Acts provides some useful insights into shipping practices during the first century of the common era. In this paper, I intend to summarise the information and clues provided in the Book of Acts and present an overview of some of the basic interpretations of the relevant passages. It is important to understand that the Book of Acts is a continuation of the gospel according to Luke and any reference to him here is in his capacity as writer of the Book. St.Paul, as a Roman prisoner, had been put in the charge of Julius, an officer in the "Emperor's Regiment" who was to take the prisoners to Rome to see the Emperor. At Caesarea, Julius had his prisoners board a ship from Adramyttium and they sailed overnight to Sidon. The next leg of their journey was more difficult as the winds were again against them. As such, they sailed the ship on the sheltered east side of the island of Cyprus, then west to In Myra, Julius moved his prisoners to a boat from Alexandria which was bound for Italy. The first leg of their journey aboard this new ship was difficult as the winds were against them. It took several days to reach Cnidus. With the wind against them still, they were forced to sail south, hoping to take shelter behind the island of Crete. Keeping close to shore, they eventually arrived at Safe Harbours, on the southern coast of Crete. Here they stayed for several days and the Book of Acts notes that St.Paul advised against continuing as the Day of Atonement had The Day of Atonement is the traditional day at which shipping would stop for the winter in anticipation of the poor weather to come. It is normally marked towards the end of September or the start of October. However St.Paul's advice fell on deaf ears and Julius chose to accept the advice of the ship's owner and captain. They pressed on towards Phoenix (on C...

price of greed essays

price of greed essays Argh matey! Welcome aboard the ship that will lead to a world of pirates. Lets be cautious now the sight of gold can make any man lust with greed and in a blink of an eye they are lost in a world of gluttony. Now will enter a place where the desire for more has taken control over many men that are now doomed. Pirates of the Caribbean: The curse of the Black Pearl is a tale of betrayal and greed; where the greed of man leads to a path of many riches but a life cursed without enrichment. The curse that will leave man always wanting more as well as the lost of their senses of life and feelings of emotions. The code of the pirates like many other codes establishes the rules pirates abide by. One of the rules the pirates go by is if a fellow shipmate gets left behind they stay behind. This gives significance to the word betrayal. In a pirates ship everyone is looking out for himself. This is similar to the real world where everyone is trying to get ahead and think of no one but himself or herself. Many choose the path of cheating and betrayals to climb the rope of success leaving behind no regrets and seeing ahead a future of fortune. The thinking of a pirate: fortune. Captain Jack Sparrow is the captain of the Black Pearl until his crew plots against him to take over the ship. Empowered by greed they were led by a new voice, Barbosa, and left Jack Sparrow in an abandon island. The treasure they seek was Cortezs gold coins. Even though stories told of a curse the pirates greed and need for treasure overtook their rationality. Cortezs curse did not stop them from stealing and this just demonstrates how greed has the power to destroy the inner morals of any human being. The greed of many is like a craving that hits every second and it cannot be contained; it has to be satisfied. Captain Barbosa tells the story of Cortezs cursed gold coins and what the curse has done to him ...

Multiculturism Essay Example | Topics and Well Written Essays - 1750 words

Multiculturism - Essay Example The idea of monoculturalism eventually gave way to the idea of multiculturalism that more than one culture could live and exist hand in hand together. This is often referred to as the â€Å"melting pot† idea, that many cultures can all live together under one ruling force. The cultures would be equal to each other, with no culture dominating over the other cultures. Eventually this idea of multiple cultures spread, to the world that we see today with many different unique cultures, promoting unity and diversity throughout the different multiculturalistic nations of the world. However, the world wasn’t always so keen on the idea of multiculturalism. History often shows the efforts of people trying to keep with monoculturalism ideas, often at the expenses of the â€Å"lesser† culture of the time. Multiculturalism is the idea that â€Å"society should consist of, or at least allow and include, distinct cultural groups, with equal status† (http://en.wikipedia.org/wiki/Multiculturalism). This idea has historically worked against the ideas of monoculturalism, which is that idea that a nation should be all the same, and made up of the same cultural identity. The idea of multiculturalism however, only applies to culture groups that have immigrated, and not to the mixing or presence of more than one culture in a indigenous place ( http://en.wikipedia.org/wiki/Multiculturalism/). The idea of multiculturalism has points on both sides of the argument. Many support it in light of equality and civil rights for all groups involved. The opposite side of the coin often sees the idea as something that is being forced upon people, and often leads to non-equality, and possibly even work against national unity ( http://en.wikipedia.org/wiki/Multiculturalism/). During the 19th century, the way Europe felt about its states, and after wars and redistribution, new states were

Quantitative reasoning and analysis week 4 Essay

Quantitative reasoning and analysis week 4 - Essay Example In order to see if this hypothesis is true I held an examination using two groups and a comic strip I printed from the internet called Today’s Dogg. The strip is a single image of a dog that is staring into an empty dog-bowl saying, â€Å"Feed me†. Next to the bowl is a phone and text which read â€Å"Buy a smart phone. It does everything.† The two groups of five were taken into two different rooms and I briefed them on what they should do. Group A was the group that held the pens in their teeth and Group B is the group that held the pen in their lips. After a few minutes I received the results. Group B’s average rating was around 3.4 as Group A’s average rating was 4.2. However, I took an extra step, I called upon other friends and family members who have not taken the exam or know anything about the experiment. I had them repeat the test and the result were as follows: Group B’s Rating was 3.3 and Group A’s rating was 3.9. Group A ha d rated the strip to be funny compared to the other group which rated as average. With this I can conclude that Fritz Strack’s Hypothesis is right. This test does show that holding a pen in one’s teeth makes jokes funnier, but why? Well there could be possible reasons for this; however, the important thing about this experiment was to establish reliability. The consistency of the results could improve by conducting repeated tests on different groups.