Chemistry at Home

Exploring the Ingredients in Everyday Products

John Emsley

• Publisher: Royal Society of Chemistry
• Year: 2015
• eBook ISBN: 9781782626374
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Chemistry
• Index: Chemistry

Hand cream, detergent, shower gel, toothpaste, toilet cleaner, air freshener, lipstick, perfume, low-fat spread, painkiller, diet drink, insect repellent… hundreds of everyday products that make our lives so much better than those of our forebears. And yet most of us know little about the ingredients they contain and why they deliver the benefits we enjoy.
Some people find it worrying when they examine the list of ingredients on a packaging label, because all they read may be unintelligible names or E numbers. It appears to be just chemicals, chemicals, chemicals. The aim of this book is to examine the ingredients more closely and explain the reasons for their being used.
Start reading and stop worrying.
Chemistry at Home has been written by award-winning popular science writer and chemist, John Emsley, using non-technical language. The book has 12 chapters, each devoted to the kinds of products we are likely to find around the home, including in the garage and the garden shed. Chemistry at Home also includes a glossary which gives more technical information about the molecules mentioned in the book.

CHAPTER 1

The Medicine Cabinet

Every home should have a medicine cabinet, which needs to be out of the reach of children. In it are kept the medicines for the various everyday afflictions that beset us, such as headaches, indigestion, coughs, colds, aches and pains, spots, cuts, sore eyes, blocked ears, warts, and other more personal problems. (Constipation relief is covered in Chapter 5.)

The family medicine cabinet might also include medication that has to be prescribed by a doctor, and while these are also products produced by pharmaceutical chemists, they are not something included here. The products in our medicine chest are:

1. Pain relief (Solpadeine^® Plus, Cuprofen^®, Disprin^®)
2. Indigestion (Rennie^® Spearmint, Alka-Seltzer^®, Zantac^®)
3. Eye wash (Optrex^®)
4. Cough medicine (Venos^® Chesty Cough Expectorant, Tixylix Dry Cough Linctus^®)
5. Earwax remover (Otex^®)
6. Cracked soles of feet (Flexitol^® Heel Balm)
7. Rheumatism avoidance and relief (Boots Glucosamine Sulphate, Ibuleve™ Gel, Voltarol^®)
8. Skin infections (Bazuka™ Gel, Canesten^®)
9. Antiseptic ointment (Savlon^®)
10. Diarrhoea (Imodium^®)
11. Sore throat remedies (Strepsils^®)
12. Anti-itching cream (Eurax^® Cream)

1. PAIN RELIEF

The Chemistry

There is no need today to suffer the everyday aches and pains that afflicted past generations. There are three popular painkilling chemicals that can be obtained over-the-counter and these are aspirin, paracetamol, and ibuprofen. Ibuprofen is a good anti-inflammatory, paracetamol is a good painkiller, while aspirin can do both but it brings the risk of stomach bleeding. These medications are also able to reduce fever, the higher temperature being a sign the immune system is fighting infection.

The best and quickest cure for headaches is paracetamol, which comes in various guises, and the one described here contains two other ingredients that can boost its performance.

The best cure for muscle and joint pain is ibuprofen, which suppresses the excess arachidonic acid that is the cause. (We need this molecule to make prostaglandins, hormones, and cell membranes.) In response to a strained muscle, an infection, or an arthritic joint, the body will produce a local excess of prostaglandins and this causes inflammation and pain. Ibuprofen blocks the enzyme that is responsible.

Aspirin is recommended as immediate treatment for someone who is suffering a stroke or heart attack because it restores blood flow by thinning the blood, which it does by controlling the cyclo-oxygenase (COX) enzymes. It can even save a life. (Older people should carry a couple of aspirin tablets with them at all times.) Aspirin counteracts the production of platelets in the blood that are designed to stop bleeding but can cause a blockage if they clump together, leading to a stroke or heart attack. For this reason, many people take a small 75 mg tablet of aspirin every day, to prevent this from happening.

There are two kinds of COX enzymes: COX1 protects the lining of the stomach and intestines, whereas COX2 triggers the release of prostaglandins that result in inflammation and pain. Ideally a painkiller should only target COX2, but aspirin targets both.

Solpadeine^® Plus

This is based on paracetamol and it acts rapidly because it can be absorbed through the stomach wall. When combined with a little codeine and caffeine it is quicker to act and its effects are longer lasting, but this carries a low risk of addiction if used over long periods because codeine is an opioid drug like morphine and heroin. (Overuse of paracetamol is also not recommended because of potential liver damage.)

Contents

Paracetamol

Codeine phosphate hemihydrate

Caffeine

Maize starch pre-gelatinised

Potassium sorbate

Povidone

Purified talc

Magnesium stearate

Microcrystalline cellulose

Stearic acid

Hypromellose

Carmoisine

Active agents

The amounts of these are: paracetamol 500 mg, codeine phosphate hemihydrate 8 mg, and caffeine 30 mg.

Maize starch pre-gelatinised is starch extracted from maize that has been heated to unravel its polymer molecules, making it easier to digest, thereby causing the tablet to break up and release its active ingredients.

Potassium sorbate is a preservative that protects the tablet against moulds and yeasts.

Povidone is a water-soluble polymer that acts as a glue to hold the ingredients in the tablet together.

Purified talc is magnesium silicate and is a soft mineral that breaks up easily. Here it is added to bulk out the tablets.

Magnesium stearate and stearic acid prevent the tablets from sticking to the equipment that compresses them into tablet form.

Microcrystalline cellulose is another bulking agent.

Hypromellose is a modified form of cellulose and it acts partly as a glue and partly as a controlled release agent for the active ingredients so that their effects will last longer.

Carmoisine is a red colourant.

There are other brands based on paracetamol, such as Panadol^® and Anadin™, as well as pharmacist and supermarket own-brands.

Cuprofen^®

In this product the pain relief comes from the action of ibuprofen, which is best for aches and pains rather than headaches.

Contents

Ibuprofen (400 mg)

Lactose

Ac-di-sol^®

Methyl cellulose (Methocel^® A4D)

Magnesium stearate

Tablet coating is

Methyl cellulose (Methocel^® E15)

Polyethylene glycol 500

Ma...

Table of contents

• Cover
• Title
• Copyright
• Disclaimers
• Preface
• Acknowledgements
• Biography
• Contents
• Technical Words You May Need to Help You Understand the Text
• Chapter 1 The Medicine Cabinet
• Chapter 2 The Utility Room
• Chapter 3 The Bathroom
• Chapter 4 The Desk
• Chapter 5 The Toilet
• Chapter 6 The Cupboard Under the Stairs
• Chapter 7 The Bedroom
• Chapter 8 The Kitchen
• Chapter 9 The Dining Room/Food and Drink
• Chapter 10 The Living Room
• Chapter 11 The Garage and the Car
• Chapter 12 The Garden Shed
• Glossary
• Sources and Web Sites
• Subject Index