My Work | CM8001 Group 26

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Question 1

a. C5H9N3

c. Amine

Question 2

a. C17H21NO

The similarities are as below:

(a) a two-carbon chain with a nitrogen at the end (marked in red)

(b) a three-atom sequence of N-C-N (marked in blue).

Due to the similarities in structure, the antihistamine will compete with histamine to bind to the histamine receptor sites on cells.

Question 3

Drugs that produce physiological response in the body	Drugs that inhibit the growth of infectious substances
Aspirin	(Keflex) Antibiotic
Morphine	Penicillin
Estrogen
Amphetamine

Question 4

The herbal supplement manufacturers are permitted to say, for example, that a particular herbal supplement addresses a nutrient deficiency, supports health, or is linked to a particular body function (like immunity or heart health). Such a claim must be followed by the words, “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.” Besides, the herbal supplement manufacturers must follow certain good manufacturing practices to ensure the identity, purity, strength, and composition of their products. If a product is found to be unsafe or otherwise unfit for human consumption, the authorities may take enforcement action to remove the product from the marketplace or work with the manufacturer to voluntarily recall the product.

Reference: https://ods.od.nih.gov/HealthInformation/DS_WhatYouNeedToKnow.aspx

Products like herbs are sometimes tainted with germs, pesticides, or toxic heavy metals. Other supplements do not contain what’s listed on the label. Still, others contain more or less than the amount of the herb listed on the label. And many have ingredients that aren’t listed on the label at all.

This problem extends beyond the supplement makers and sellers. Some herbal suppliers (those who grow, harvest, or sell the crops) may mix or even substitute their crops with less expensive or more readily available plants. There’s also the problem of accidental contamination when one plant grows in with others, as well as cases of mistaken identity (when one plant looks like another). Given the global market, all of these problems can make it harder for a company to be sure that what they thought they were buying to make supplements is actually the herb they wanted.

b. There are limits for the safety and quality levels for heavy metals and microbial in the supplement.

“The product label should be prominently and conspicuously displayed on the product at the point of sale. Where the size, shape or nature of the final product or package does not permit the full listing of labelling information, the use of inserts, leaflets, hang tags, in appropriate format, will be allowed. However, the name of the product, the recommended dosage, the batch reference and relevant precautionary statements should be displayed on the final product or package.”

Reference: http://www.hsa.gov.sg/content/dam/HSA/HPRG/Complementary_Health_Products/Overview_Framework_Policies/Health_Supplements/HSGuidelines.pdf

Question 1:

Polymer is dissolved by the acetone, hence the gas of the foaming agent freely escapes. The polymer collapses on itself and is more dense because the gas has been expelled.

Question 2:

a. LDPE cannot be used in this application because the material is not strong enough.

b. The molecules of HDPE must line up according to the way that generates enough strength. Using linear HDPE is successful because it allows sufficient flexibility.

LDPE	HDPE

Question 3:

When the piece of plastic bag is stretched, the strip becomes narrow. The molecules are aligned parallel to each other according to the direction of the pull. This is a irreversible alteration of the three-dimensional structure, hence if the pulling persists, the plastic breaks. If this same pulling force is applied to a piece of paper, the paper will tear because it does not have stretching properties. The cellulose molecules in paper are held far more rigidly in place, and are not free to become aligned.

Question 4:

a. The benefits for polymers intended for use in the body should far outweigh any risks. The two main properties are:

stable over time of intended use
non-toxic

Other factors to consider are:

low cost
lack of solubility in body fluids
lack of reactivity in body fluids
ease of implantation

b. Several different types of contact lenses are on the market and each uses a different type of polymer. Polymethyl methacrylate (PMMA), one of the earliest polymers used for rigid gas permeable lenses, is structurally similar to Lucite and plexiglass. Silicone-acrylate materials now are more commonly used under trade names such as Kolfocon. Newer rigid gas permeable (GRP) polymers contain fluorine: fluoro-silicone-acrylate polymers and fluoro-silicones. Polymacon (38% water) is typical of the polymers used for soft lenses and is a polymer of 2-hydroxyethyl methacrylate (HEMA). Other methacrylates include hioxifilcon (48% water) and methafilcon (55% water) or even lidofilcon (70% water). Manufacturers’ websites are good sources of information.

The desirable properties in these polymer materials are:

Unreactive to chemicals on the eye surface
Lets oxygen pass through the eye surface
Transparent and moderately flexible
Low density
Easy to manufacture from a raw material that is available in abundance

c. Difference in material used in “hard” and “soft” contact lenses

Hard	Soft
Polymethyl methacrylate (PMMA)	Polyacrylamide
Does not contain nitrogen	Contains nitrogen atoms in its structure
	When polyacrylamide chains are cross-linked, the material absorbs water
	Hydrophilic (water-loving)

How it affects the ease of wearing of contact lenses:

Hard	Soft
Less comfortable because PMMA is a rigid non-gas permeable plastic	More comfortable because it is made of silicon and allows oxygen to go through/reach the eye

CM8001 Group 26

Category Archives: My Work

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