Disinfectant

With the occurence of the virus influenza H1N1, disinfectant has become a popular demand worldwide.


Disinfectants are antimicrobial agents that can be used to kill the microorganisms.

Hand wash sanitizers is also a type of disinfectants.

Sanitizers are substances that are able to reduce the level of microorganism to a safe level, or more specifically they have to be able to kill 99.999% of microorganisms.

The main difference between disinfectants and sanitizers is the specific use of dilution.


And disinfectants have higher capability to kill off the pathogenic bacteria compared to sanitizers.

Disinfectants are often used in hospitals, kitchens, or bathrooms, to kill infectious microorganisms.

There are a few types of disinfectants, the most common would be the one using alcohols.
Alcohols can be used for disinfectants, but more often being used for antiseptic( applied on living things).

There are also some disinfectants which use aldehydes.
Aldehydes such as glutaraldehyde, have a wide microbiocidal activity and are fungicidal and sporocidal.

However, glutaraldehyde could cause asthma and some other health problems, hence it is replaced by Ortho-phthalaldehyde.

Besides oxidizing agents can also be used as disinfectant.

This is because oxidizing agents are able to oxidise the membrane of microorganisms, which can cause the microorganisms to lyse (cell contents spilled out) and dead.

Chlorine and oxygen are strong oxidizers, therefore most of the oxidizing agents contains these 2 elements in them.

For example:

- Chloramine

- Chlorine dioxide

- Hydrogen peroxide

- Potassium permanganate

- and many more......

Shampoo

Shampoo is defined as a type of hair-care product used to remove oil, skin particles, dandruff, and other environmental pollutants that gradually build up in hair.

The word 'shampoo' means head massage in several North Indian languages. And the word was introduced to Britain from colonial India.

The word 'shampoo' in English is derived from Hindi chāmpo.

During early stages of shampoo, it is made by boiling shaved soap in water, and herbs were added to give the hair shine and flagrance.
Originally, shampoo and soap have similar properties, this is because both contains surfactants (a type of detergent).

Modern shampoo was first introduced around 1930s with Drene, the first non-soap shampoo.

So how does shampoo works?

Shampoo will strip the sebum from the hair.
Sebum is the oil secreted by hair follicles, and it will be absorbed by the hair, forming a protective layer on the hair. This will protect the hair protein from damage.

However, this protective layer tends to collect dirt and scalp flakes. Therefore surfactants in shampoo will strip the sebum from the hair, thus removing the dirt attached to the sebum layer as well.

Although both soap and shampoo contains surfactants, but soap bonds to the oils with much higher affinity, that it will remove too much oil on hair.
Shampoo contains different class of surfactants that are balanced to avoid excessive oil removal from the hair.

Shampoo formulations will normally try to maximize the following qualities:
- easy rinsing
- minimal skin or eye irritation
- no damage to hair
- pleasant flagrance
- low toxicity
- slightly acidic(pH less than 7), this is because basic environment will break the disulfide bonds in hair keratin, causing the hair to be weaken
- and more.........

Some of the common ingredients found in shampoo are:
- ammonium chloride
- ammonium lauryl sulfate
- glycol
- sodium lauryl sulfate

There are also some 'specialized' shampoo which has some other functions besides removing sebum from hair.

For example, anti-dandruff shampoo.
This type of shampoo contains fungicides( chemical compounds used to kill or inhibit fungi or fungal spores).
Fungicides that present in anti-dandruff shampoo are ketaconazole, zinc pyrithione and so on.
Those fungicides will kill the Malassezia furfur which is the main cause of dandruff.

Toothpaste

Everyone have to brush their teeth at least twice in a day.

Do you ever wonder since when human have started using toothpaste?
Or the ingredients present in modern toothpastes?

The earliest toothpaste usage can be traced back to 4th century A.D., a manuscript from Egypt describes toothpaste as 'a mixture of iris flowers'.

Early toothpastes were made by adding ingredients such as crushed bones and oyster shells, during the time of ancient Greece and Rome.

However, toothpaste did not come into general use until the 19th century.

Let's look at some history of toothpaste:
-By 1900, toothpaste was made of hydrogen peroxide and baking soda.

-Toothpaste was first manufactured in the form of collapsible tube in 1892, and was called 'Dr. Sheffield's Creme Dentifrice'.

-Fluoride was first added to toothpastes in 1914, but were only approved by American Dental Association (ADA) in the 1950s after much development of the toothpaste.

-Striped toothpaste was invented in 1955.

So, what are the ingredients present in the modern toothpaste?

1 of most common ingredient would be fluoride.
Fluoride in toothpaste is able to prevent cavities (caused by decaying of tooth).

Fluoride can be present in various forms in the toothpaste:
- Sodium fluoride (NaF) is the most common form
- Sodium monofluorophosphate (Na₂PO₃F) in some of the brands of toothpaste.
- Organic amine fluoride(AmF)

The next common ingredient in toothpaste would be an abrasive (sand like structure used to polish or cleaning a surface).
Abrasive is able to cause small amount of enamel erosion, which is termed 'polishing' action.

Ingredients like baking soda, enzymes, vitamins, herbs and mouthwash can also be found in toothpaste.

Sometimes antibacterial agents like zinc chloride or triclosan( common in UK) are also added to the toothpaste.
Besides, bases like sodium hydroxide would also being added to toothpaste to neutralize acids.

Modern toothpaste normally comes with colouring and flavours.
The most common flavouring would be some variation on mint.
Some other less common flavouring would be like cinnamon, lavender, ginger, vanilla, and lots more........

Normally toothpaste cannot be swallowed after brushing your teeth. Except those used by pets or astronauts.
Swallowing toothpaste could cause nausea or diarrhea.
Fluoride toothpaste could also be toxic if too much of it was swallowed.

Besides, actually fluoride toothpaste is not suitable to be used by children.
Because excessive consumption of toothpaste on the teeth which is still developing, could cause fluorosis.