Category Archives: General

Any odd comment on Chemistry or life in general.

Molecule of the Month (November 2012) – Varenicline

Now students, it is not a secret. Many students abuse nicotine. If you wish to clear your life of it, now is the time! There are numerous ways, but here is one pharmacological way. There are risks however, so please read carefully. Nonetheless, ENJOY this post =)

Maxim Yap
HoD Chemistry 2012

From Wikipedia, the Free Encyclopedia

Varenicline (trade name Chantix in the USA and Champix in Canada, Europe and other countries, marketed by Pfizer, usually in the form of varenicline tartrate), is a prescription medication used to treat smoking addiction. Varenicline stimulates nicotine receptors more weakly than nicotine does, that is, it is a nicotinic receptor partial agonist. In this respect it is similar to cytisine and different from the nicotinic antagonist, bupropion, and nicotine replacement therapies (NRTs) like nicotine patches and nicotine gum. As a partial agonist it both reduces cravings for and decreases the pleasurable effects of cigarettes and other tobacco products. Through these mechanisms it can assist some patients to quit smoking.

Medical uses

Varenicline is indicated for smoking cessation. It is more effective than NRTs and nicotine agonists. In a 2006 randomized controlled trial sponsored by Pfizer, after one year the rate of continuous abstinence was 10% for placebo, 15% for bupropion and 23% for varenicline.In a 2009 meta-analysis of 101 studies funded by Pfizer, varenicline was found to be more effective than bupropion (odds ratio 1.40) and NRTs (odds ratio 1.56).

A Cochrane systematic review concluded that both varenicline and bupropion improved smoking cessation. More people quit with varenicline than with bupropion, but the difference was not statistically significant.

The FDA has approved its use for twelve weeks. If smoking cessation has been achieved it may be continued for another twelve weeks.

Varenicline has not been tested in those under 18 years old or pregnant women and therefore is not recommended for use by these groups.

Adverse effects

Nausea occurs commonly in people taking varenicline. Other less common side effects include headache, difficulty sleeping, and abnormal dreams. Rare side effects reported by people taking varenicline compared to placebo include change in taste, vomiting, abdominal pain, flatulence, and constipation. In a recent meta-analysis paper by Leung et al, it has been estimated that for every 5 subjects taking varenicline at maintenance doses (1mg twice daily), there will be an event of nausea, and for every 24 and 35 treated subjects, there will be an event of constipation and flatulence respectively. Gastrointestinal side-effects are important factors compromising the compliance of varenicline.

Depression and suicide

In November 2007, the FDA announced it had received post-marketing reports that patients using varenicline for smoking cessation had experienced several serious side-effects, including suicidal ideation and occasional suicidal behavior, erratic behavior, and drowsiness. On February 1, 2008 the FDA issued an alert to further clarify its findings, noting that “it appears increasingly likely that there is an association between Chantix and serious neuropsychiatric symptoms.” It is unknown whether the psychiatric symptoms are related to the drug or to nicotine withdrawal symptoms, although not all patients had stopped smoking. The FDA also recommended that health care professionals and patients watch for behavioral and mood changes.In May 2008, Pfizer updated the safety information associated with varenicline, noting that “some patients have reported changes in behavior, agitation, depressed mood, suicidal thoughts or actions.” While it is unclear whether or not a small subgroup of people develop depression and suicidal ideation as a result of varenicline or smoking cessation itself, there is evidence that varenicline, similar to nicotine, has antidepressant properties and the use of varenicline for smoking cessation leads to a reduced rate of initiation of antidepressant pharmacotherapy.

As of July 1, 2009, the US Food and Drug Administration requires Chantix (varenicline) to carry a black box warning, the agency’s strongest safety warning, due to public reports of side effects including depression, suicidal thoughts, and suicidal actions.

Cardiovascular disease

On June 16, 2011, the FDA issued a safety announcement that Chantix may be associated with “a small, increased risk of certain cardiovascular adverse events in patients who have cardiovascular disease.”

On July 4, 2011, four scientists published a review of double-blind studies in the Canadian Medical Association Journal. They found that varenicline has increased risk of serious adverse cardiovascular events compared with placebo.

Mechanism of action

Varenicline is a partial agonist of the α4β2 subtype of the nicotinic acetylcholine receptor. In addition it acts on α3β4 and weakly on α3β2 and α6-containing receptors. A full agonism was displayed on α7-receptors.

Acting as a partial agonist varenicline binds to, and partially stimulates, the α4β2 receptor without producing a full effect like nicotine. Thus varenicline does not greatly increase the downstream release of dopamine. Due to its competitive binding on these receptors, varenicline blocks the ability of nicotine to bind and stimulate the mesolimbic dopamine system, akin to the action of buprenorphine in the treatment of opioid addiction.

Varenicline also acts as an agonist at 5-HT3 receptors, which may contribute to mood altering effects of varenicline.


Most of the active compound is excreted renally (92–93%). A small proportion is glucuronidated, oxidated, N-formylated or conjugated to a hexose. The elimination half-life is about 24 hours.


Varenicline was discovered at Pfizer through the research aimed at modifying the structure of cytisine.

Varenicline received a “priority review” by the U.S. Food and Drug Administration (FDA) in February 2006, shortening the usual 10-month review period to 6 months because of its demonstrated effectiveness in clinical trials and perceived lack of safety issues. The agency’s approval of the drug came on May 11, 2006. August 1, 2006, varenicline was made available for sale in the United States and on September 29, 2006, was approved for sale in the European Union.

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Filed under Applications of Chemistry, Chemistry, Design and materials, General

Welcome to our Cohort 2 Students!

Happy Leap Year 29th February 2012 everyone! With the start of March comes a new beginning for our Cohort 2 Chemistry students. Start off fresh and on the ball, and you will end up with better results than you expected! On behalf of the PTEK Chemistry Department, I bid you all welcome, and wish you all the very best in your endeavors in A-Level Chemistry.

Do NOT underestimate this subject (as well as any other subject for that matter), and you will be well on your way towards a successful future.

Before we begin anything, please take the time to read about Safety in the Laboratory. It is imperative that we behave as scientists in the science laboratory. For more information, here is the full document regarding Safety!

Please download a copy of the CIE 9701 A-Level Chemistry Syllabus for your reference. I advise that you use this as a checklist for your revision purposes. Put a tick after each time you have been delivered material by your tutors, and then a second tick when you have understood the concept. That way you will be able to plan your revision well in the future. Of course, by the time you see 3 ticks on every objective in the syllabus, you should be ready for almost ANY question that CIE can throw your way. Also, you should print out a copy of the Practical Assessment (Qualitative Analysis) Notes as they will be used in EVERY Practical Session. They can be found on pages 69-70 of the Syllabus.

We INSIST that you all visit this website often to keep yourself up to date with anything involving PTEK Chemistry. Resources will be put up as we go along, maybe some worksheets, mark schemes and please take note at the very bottom of this page… the COUNTDOWN to your First APR. =) They should begin roughly around the 9th of April, 2012.

Being prepared is half the battle won!

Maxim Yap
HoD Chemistry 2012

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Molecule of the Month (March) – Ibuprofen

From Wikipedia:

Ibuprofen (INN); from the nomenclature iso-butyl-propanoic-phenolic acid) is a nonsteroidal anti-inflammatory drug (NSAID) used for relief of symptoms of arthritis, fever, as an analgesic (pain reliever), especially where there is an inflammatory component, and dysmenorrhea.

Ibuprofen is known to have an antiplatelet effect, though it is relatively mild and somewhat short-lived when compared with aspirin or other better-known antiplatelet drugs. In general, ibuprofen also acts as a vasodilator, having been shown to dilate coronary arteries and some other blood vessels. Ibuprofen is a core medicine in the World Health Organization‘s “WHO Model List of Essential Medicines“, which is a list of minimum medical needs for a basic healthcare system.

Ibuprofen was derived from propionic acid by the research arm of Boots Group during the 1960s. It was discovered by Andrew RM Dunlop, with colleagues Stewart Adams, John Nicholson, Vonleigh Simmons, Jeff Wilson and Colin Burrows, and was patented in 1961. Originally marketed as Brufen, ibuprofen is available under a variety of popular trademarks, including Motrin, Nurofen, Advil, and Nuprin.

Chemical Structure of Ibuprofen

Athletes, the young, the old, the sick alike all use Ibuprofen. Can you recall the last time you were prescribed this chemical? Take care though… from personal experience, this drug, as well as most drugs… cause gastric discomfort 😦

Ibuprofen Tablets




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24/7 Access to Chemistry @ PTEK

A very warm welcome to all students, AE and BE (cohort 1 and 2) alike! Welcome to 2012 PTEK Chemistry. Be proud… for you are among those who will pioneer our latest approach to Chemistry that prioritizes communication online.

We are currently in the process of moving archives from as well as various excerpts and notes from revision guides found online. Please be patient with us as we will get this blog running as soon as possible.

Here you will find various resources, lesson notes, test papers, mark schemes, etc.

Moreover, you will be able to post questions to specific tutors or all tutors and peers in general. However, we would prefer that smaller questions be sent to our FaceBook Group PTEK Chemistry, and larger questions be sent to individual emails that your respective tutors will supply you if they wish.

Once again, welcome to a new Academic Year in PTEK Chemistry. All the best in your endeavors and on behalf of the Chemistry Department, I wish you all the best of luck in your studies!

Maxim Yap
HoD Chemistry 2012


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