chemistry

Polystyrene sulfonate

Polystyrene sulfonate is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Polystyrene sulfonate rather than just read about it. In short: Polystyrene sulfonates are a group of medications used to treat high blood potassium. Therapeutic effects generally appear hours to days after commencement of therapy.

Key takeaways

Polystyrene sulfonate belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Polystyrene sulfonate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Polystyrene sulfonate from memory before moving on to harder problems.

Reference excerpt

Polystyrene sulfonates are a group of medications used to treat high blood potassium. Therapeutic effects generally appear hours to days after commencement of therapy. Common side effects include loss of appetite, gastrointestinal upset, constipation, and low blood calcium. Polystyrene sulfonates are given by mouth with a meal, or rectally by retention enema. Oral formulations often also contain the laxative sorbitol in order to lessen the risk of constipation which can be severe. Polystyrene sulfonates are derived from polystyrene by the addition of sulfonate functional groups. Sodium polystyrene sulfonate was approved for medical use in the United States in 1958. A polystyrene sulfonate was developed in the 2000s to treat Clostridioides difficile associated diarrhea under the name Tolevamer, but it was never marketed. Polystyrene sulfonates are also used in technical applications to remove potassium, calcium, and sodium from solutions.

Medical uses

Polystyrene sulfonate is typically supplied in the form of either a sodium or a calcium salt. It is used medically as a potassium binder in hyperkalemia (high blood potassium) occurring in the context of acute and chronic kidney disease. The medication has a delayed onset of action and is effective in sequestering potassium over the longer-term, however, its effectiveness in acute management of hyperkalemia is tenuous.

Adverse effects

Gastrointestinal Intestinal disturbances are common, including loss of appetite, nausea, vomiting, and constipation. Constipation can be severe, culminating in life-threatening fecal impaction. In rare cases, use has been associated with colonic necrosis.

Gastrointestinal injury Severe gastrointestinal complications are relatively rare, however, use of this medication is widespread (e.g., about 5 million doses prescribed per year in the U.S.) in spite of poor evidence for its efficacy and availability of alternative treatments, so a large population of patients is subject to potentially unnecessarily risk of GI injury. No statistically rigorous evidence regarding the actual incidence of severe GI adverse effects with this medication is available. GI injury occurs both with polystyrene sulfonate alone or in formulations containing sorbitol. It can occur with oral or rectal administration. Polystyrene sulfonate may be directly toxic to the intestinal mucosa, inducing a local inflammatory response that causes vascular injury. Co-administration of sorbitol is thought to compound the risk of GI injury by independently promoting vascular injury by causing vasospasm and prostaglandin-mediated pro-inflammatory effects. Mortality in cases with severe GI injury is high (possibly due to co-morbidities in affected patients). The large intestine is most commonly affected, however, with oral administration, more proximal GI segments (including the stomach and oesophagus) are affected in about 30% of cases (usually with concurrent large intestine involvement). Milder and less clearly attributable cases of GI injury may go unnoted. Numerous comorbidities and risk factors may predispose individuals to severe GI complications (notably kidney disease, solid organ transplantation with immunosuppressive medication use, and post-operative state), possibly by promoting GI vasoconstriction or impairing intestinal regeneration or causing impaired GI mobility.

Electrolyte changes Changes in electrolyte blood levels such as hypomagnesemia, hypocalcemia, and hypokalemia may occur.

Contraindications Polystyrene sulfonates should not be used in people with obstructive bowel disease and in newborns with reduced gut motility.

Interactions Polystyrene sulfonates can bind to various drugs within the digestive tract and thus lower their absorption and effectiveness. Common examples include lithium, thyroxine, and digitalis. In September 2017, the FDA recommended separating the dosing of polystyrene sulfonate from any other oral medications by at least three hours to avoid any potential interactions.

Mechanism of action Polystyrene sulfonates release sodium or calcium ions in the stomach in exchange for hydrogen ions. When the resin reaches the large intestine the hydrogen ions are exchanged for free potassium ions, and the resin is then eliminated in the feces. The net effect is lowering the amount of potassium available for absorption into the blood and increasing the amount that is excreted via the feces. The effect is a reduction of potassium levels in the body, at a capacity of 1 mEq of potassium exchanged per 1 g of resin. The fact that the medication's site of action is the large intestine explains the delayed and prolonged effects seen with oral administration.

Production and chemical structure Polystyrene sulfonic acid, the acid whose salts are the polystyrene sulfonates, has the idealized formula (CH2CHC6H4SO3H)n. The material is prepared by sulfonation of polystyrene:

(CH2CHC6H5)n + n SO3 → (CH2CHC6H4SO3H)n Several methods exist for this conversion, which can lead to varying degree of sulfonation. Usually the polystyrene is crosslinked, which keeps the polymer from dissolving. Since the sulfonic acid group (SO3H) is strongly acidic, this polymer neutralizes bases. In this way, various salts of the polymer can be prepared, leading to sodium, calcium, and other salts:

(CH2CHC6H4SO3H)n + n NaOH → (CH2CHC6H4SO3Na)n + n H2O These ion-containing polymers are called ionomers.

Alternative sulfonation methods Double substitutions of the phenyl rings are known to occur, even with conversions well below 100%. Crosslinking reactions are also found, where condensation of two sulfonic acid groups yields a sulfonyl crosslink. On the other hand, the use of milder conditions such as acetyl sulfate leads to incomplete sulfonation. Recently, the atom transfer radical polymerization (ATRP) of protected styrene sulfonates has been reported, leading to well defined linear polymers, as well as more complicated molecular architectures.

Chemical uses Polystyrene sulfonates are useful because of their ion exchange properties. Linear ionic polymers are generally water-soluble, whereas cross-linked materials (called resins) do not dissolve in water. These polymers are classified as polysalts and ionomers.

Water softening

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Polystyrene sulfonate

Start with the simplest possible case. Write down what Polystyrene sulfonate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Polystyrene sulfonate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Polystyrene sulfonate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Polystyrene sulfonate

In research: Polystyrene sulfonate appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Polystyrene sulfonate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Polystyrene sulfonate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Acid catalysts, Benzenesulfonates, Chelating agents used as drugs, so understanding it makes those chapters shorter.
In everyday life: Look for Polystyrene sulfonate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Polystyrene sulfonate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Polystyrene sulfonate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Polystyrene sulfonate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Polystyrene sulfonate in simple terms?

Polystyrene sulfonates are a group of medications used to treat high blood potassium. Therapeutic effects generally appear hours to days after commencement of therapy.

Why does Polystyrene sulfonate matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Polystyrene sulfonate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Polystyrene sulfonate.