Phenolphthalein

Description

Forensic scientists use phenolphthalein, a chemical indicator, in the Kastle-Meyer presumptive blood test. Phenolphthalein mixed with hydrogen peroxide turns pink when blood is present.

Chemical properties

white to light yellow crystal powde

The Uses of Phenolphthalein

Phenolphthalein is one of those chemicals that is commonly used in the chemistry laboratory to tell if a solution is acidic or alkaline . These chemicals are called acid - base indicators and used as indicator for acidimetric titrations. Phenolphthalein exerts laxative effects by stimulating the intestinal mucosa and constricting smooth muscles. However, phenolphthalein is no longer used as a laxative due to the suspected carcinogenicity of this compound.

The Uses of Phenolphthalein

Phenolphthalein can be used as an inhibitor and pH indicator. It also induces centrosome amplification and tubulin depolymerization in vitro.

Background

Phenolphthalein was withdrawn in Canada due to concerns with carcinogenicity in 1997.

Indications

Used for over a century as a laxative.

What are the applications of Application

Phenolphthalein is a commonly used colorimetric pH indicator

Definition

An acid–base indicator that is colorless in acid solutions and becomes red if the pH rises above the transition range of 8–9.6. It is used as the indicator in titrations for which the end point lies clearly on the basic side (pH>7), e.g. oxalic acid or potassium hydrogentartrate against caustic soda.

Definition

phenolphthalein: A dye used as anacid-base indicator. It is colourlessbelow pH 8 and red above pH 9.6. Itis used in titrations involving weakacids and strong bases. It is also usedas a laxative.

brand name

Evac-Q-Tabs (Savage); Ex-Lax (Novartis); Modane (Savage); Prulet (Mission Pharmacal);Agaffin;Alophen pills;Anodyne dellipsoids 4;Ap-la-day;Bold laxine;Bom-bon;Bon-bon;Canisan;Certolax;D & m tablets;Darmol;Euchessinia;Evac-qwik tablets;Evactil;Feen-a-mint;Fractines vichy;Fractine-vichy;Fructines-vichy;Kalimalterin;Kest;Kondremul with phenolphtalein;Laxante yer;Laxatabs;Laxatone;Laxen busto;Minilax;Modane plus;Mucinum;Musilaks;Neoprunex;Neopurghes;Novopuren;Paradeines;Peplax;Petrolaglar emulsion;Petro-mul-phen;Phillips laxcaps;Prifunal;Prunetta;Pugrante el aleman;Purganol;Purganos-daguin;Purgant aleman;Purgante orravan;Purgenum;Purgestol;Purgoids;Purgyl;Purjen sahap;Sarolax;Thalinol mrt;Unisvelt;Veracolate.

World Health Organization (WHO)

Phenolphthalein has been widely used as a laxative since its cathartic activity was first described in 1902. Because it undergoes enterohepatic circulation it is eliminated slowly and it has been associated with adverse effects, notably skin reactions, potassium loss and atonia. This has led to the withdrawal of phenolphthalein from pharmaceutical preparations in several countries. Elsewhere, it remains available, often in over-the-counter preparations.

General Description

Phenolphthalein solution is a synthetic indicator. It is colorless in acidic and neutral conditions. Phenolphthalein gives pink color when added to a base, therefore it is considered as a base indicator.

Safety Profile

Confirmed carcinogen. US Food and Drug Administration recommends removal from laxative formulations. Moderately toxic by intraperitoneal route. Human systemic effects: changes in urine composition, gastritis, nausea or vomiting. Used in medicine as a laxative; in chemistry as an indicator. When heated to decomposition it emits acrid smoke and irritating fumes

Carcinogenicity

Phenolphthalein is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.

Metabolism

Not Available

Purification Methods

Dissolve it in EtOH (7mL/g), then dilute it with eight volumes of cold water, filter and heat on a water-bath to remove most of the alcohol and the phenolphthalein that precipitates is filtered off and dried in vacuo.[Beilstein 18 II 119, 18 III/1V 1945, 18/4 V 188.]