Assay of Chlorpromazine: Medicinal Chemistry Practical
BP406P Medicinal Chemistry I Practical
AIM:To carry out the Assay of Chlorpromazine.
REFERENCE:Indian Pharmacopoeia 2018 page no:1600-01.
REQUIREMENTS:
Perchloric acid (0.1M),Chlorpromazine, mercuric acetate solution(5% w/v in acetic acid),crystal violet solution (0.2%w/v in acetic acid),acetone,methyl orange indicator, conical flask, burette, beaker, potassium hydrogen phthalate, glacial acetic acid, crystal violet indicator.
PRINCIPLE:
Chlorpromazine is estimated by non-aqueous titration which is suitable for titration of weak acid and weak base. In this non aqueous solvent like perchloric acid is utilized as a titrant and methyl orange is used as an indicator. Mercuric acetate is added in the non-aqueous titration in order to remove the chloride ions. So as to prevent the interference of the chloride ion released by the titrant. The mercuric acetate replaces the halide ion in chlorpromazine with acetate ion which is a strong base. The end point is indicated by appearance of blue colour.
PROCEDURE:
- STANDARDISATION OF PERCHLORIC ACID (0.1N)
Dissolved 0.5g of potassium hydrogen phthalate in 25ml of glacial acetic acid and added few drops of 5%w/v crystal violet indicator. Titrated the solution with 0.1N perchloric acid till blue green colour appears.
ASSAY OF CHLORPROMAZINE
Weighed accurately about 0.6g and dissolved in 200 ml of acetone. Added 15ml of mercuric acetate solution. Titrated with 0.1M perchloric acid, using a saturated solution of methyl orange in acetone as indicator. Perform a blank determination and make a necessary correction.
Each ml of 0.1M perchloric acid equivalent to 0.03553g of C17H19ClN2S,HCl
REPORT:
The given sample contains …………………. mg of chlorpromazine
Which indicators are used in non aqueous titration?
Phenolphthalein: Phenolphthalein is a commonly used indicator in non-aqueous titrations. It is colorless in acidic solutions and turns pink or red in alkaline solutions. It is often used for titrations involving weak acids and strong bases in non-aqueous solvents.
Bromothymol Blue: Bromothymol Blue is another indicator used in non-aqueous titrations. It is yellow in acidic solutions and blue in alkaline solutions. It is suitable for titrations involving strong acids and strong bases in non-aqueous solvents.
Thymol Blue: Thymol Blue is an indicator that changes color from red to yellow in the presence of acid and from yellow to blue in the presence of base. It is often used for titrations involving weak acids and weak bases in non-aqueous solvents.
Methyl Orange: Methyl Orange is an indicator that transitions from red in acidic solutions to yellow in alkaline solutions. It is commonly used for titrations involving strong acids and weak bases in non-aqueous solvents.
Crystal Violet: Crystal Violet is a purple dye that changes color from purple to yellow in the presence of acid. It is used as an indicator for titrations involving weak acids and strong bases in non-aqueous solvents.
Cresol Red: Cresol Red is an indicator that undergoes a color change from yellow to red in the presence of acid and from red to yellow in the presence of base. It is suitable for titrations involving weak acids and weak bases in non-aqueous solvents.
Perchloric Acid (HClO4): Perchloric acid is a strong acid commonly used as a titrant in non-aqueous titrations. It is often employed for the titration of bases in non-aqueous solvents.
Tetrafluoroboric Acid (HBF4): Tetrafluoroboric acid is another strong acid used as a titrant in non-aqueous titrations. It is often utilized for the titration of amines and other basic compounds in non-aqueous solvents.
Tetrabutylammonium Hydroxide (TBAOH): Tetrabutylammonium hydroxide is a strong base that is commonly used as a titrant in non-aqueous titrations. It is often employed for the titration of acids in non-aqueous solvents.
Lithium Aluminum Hydride (LiAlH4): Lithium aluminum hydride is a reducing agent that can be used as a titrant in non-aqueous titrations. It is often utilized for the titration of carbonyl compounds, such as aldehydes and ketones, in non-aqueous solvents.
Sodium Methoxide (NaOCH3): Sodium methoxide is a strong base commonly used as a titrant in non-aqueous titrations. It is often employed for the titration of acids and acid derivatives, such as esters, in non-aqueous solvents.
Silver Nitrate (AgNO3): Silver nitrate is sometimes used as a titrant in non-aqueous titrations, particularly for the determination of halides, such as chloride, bromide, and iodide, in non-aqueous solvents.
Titration of Amines: Amines, which are weak bases, can be titrated with perchloric acid in non-aqueous solvents. The titration can be performed using a suitable indicator such as phenolphthalein or bromothymol blue. The endpoint is reached when the indicator changes color, indicating the complete neutralization of the amine.
Titration of Organic Bases: Various organic bases, such as pyridine or aniline, can be titrated with perchloric acid in non-aqueous solvents. These titrations are typically carried out in solvents like acetic acid, acetonitrile, or ethanol. The endpoint can be determined using indicators like phenolphthalein or methyl orange.
Titration of Weak Basic Drug Substances: In pharmaceutical analysis, weak basic drug substances that exhibit basicity in non-aqueous solvents can be titrated with perchloric acid. The endpoint can be detected using indicators such as bromothymol blue or crystal violet.
Interesting facts about Chlorpromazine
Certainly! Here are some interesting facts about chlorpromazine:
- Discovery and Early Use: Chlorpromazine, also known by its brand name Thorazine, was first synthesized in the 1950s by a French pharmaceutical company called Rhône-Poulenc. It was initially developed as an antihistamine but was later found to have profound effects on the central nervous system.
- Antipsychotic Medication: Chlorpromazine is classified as a first-generation or typical antipsychotic medication. It was one of the first drugs introduced for the treatment of psychotic disorders, particularly schizophrenia. Its introduction revolutionized the field of psychiatry, as it provided a significant improvement in managing the symptoms of schizophrenia.
- Dopamine Blockade: Chlorpromazine exerts its antipsychotic effects by blocking dopamine receptors in the brain. It primarily targets D2 receptors, reducing the excessive dopaminergic activity associated with psychosis. This dopamine-blocking mechanism is still a cornerstone of antipsychotic pharmacology.
- Widespread Use: Chlorpromazine gained widespread use and popularity as an antipsychotic medication. It was considered a breakthrough in the treatment of schizophrenia and played a pivotal role in deinstitutionalizing psychiatric patients by providing an effective alternative to long-term hospitalization.
- Other Medical Uses: Apart from its antipsychotic properties, chlorpromazine has been found to have several other medical uses. It is used as an antiemetic (to prevent nausea and vomiting), as a sedative in the management of agitation and anxiety, and as an adjunctive treatment for hiccups.
- Influence on Psychiatric Treatment: The introduction of chlorpromazine sparked a significant shift in the treatment of mental illnesses. Its success paved the way for the development of other antipsychotic medications and opened doors for further research into understanding the neurochemical basis of psychiatric disorders.
- Side Effects: Like many medications, chlorpromazine can cause side effects. Some common side effects include sedation, dry mouth, blurred vision, constipation, and dizziness. It may also cause more serious side effects such as movement disorders, cardiac effects, and neuroleptic malignant syndrome (a potentially life-threatening condition).
- Historical Significance: Chlorpromazine’s impact on the treatment of schizophrenia and the field of psychiatry was so profound that it is considered one of the most important discoveries in psychopharmacology. It played a crucial role in shifting the focus of psychiatric treatment from primarily psychoanalytic approaches to a more biological and pharmacological model.
It’s important to note that the information provided here is for educational purposes only, and if you have any specific questions or concerns about chlorpromazine or any other medication, it is always best to consult with a healthcare professional or pharmacist.
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