Core Concepts in Pharmaceutical Chemistry and Drug Analysis
Pharmaceutical chemistry is a Branch of chemistry which deals with the study of organic chemistry (Molecules & Compound) In combination with structural & chemical biology & pharmacology for producing pharmaceutical drugs & medicines.
Scope of Pharmaceutical chemistry:
➢ Quality Assurance & Quality control (QA & QC):- Processes & standards that ensure quality of drug compounds. ➢ Drug Discovery: – Identifying compound, especially those that treat disease. ➢ Industry:– ➢ Pharmaceutical chemistry Teacher for College institute etc.
Errors is define as the deformity present in any measurements by addition of any internal or external factor.
Depending on the calculative nature errors are categorized into two parts.
Absolute Errors— Difference between experimental mean value and true/actual value is known as absolute errors. Absolute errors may be positive and negative. Absolute errors = Measures mean value – True value Relative Errors— Relative error is defined by dividing the absolute errors by the true values. It is generally expressed as percentage, that is by the multiplying the relative error by 100 or by expressing it as parts per thousand by multiplying the relative error by 1000.
On the basis of nature and source errors are categorized into two principles
1. Determinate or Systematic Errors— Systematic errors are arises due to the wrong procedure, wrong measurement (pipettes, burette, volumetric flasks) and faulty instruments (calibrated balance and machinery system). Systemic error is under the control of the analyst because it is easily detectable and can be eliminated to a large extent. Sources of systematic Errors— sources are mentions below. Instrumental Errors— Due to the use of defective equipment or low quality instruments, errors are arises in the analytical procedure. It is easily checkable by the analyst. Proportional Errors— The absolute value of this kind of the errors changes with the size of the sample in such a fashion that the relative error remains constant. It is easily incorporated by a material that directly interferes in analytical process. Personal Errors— Errors are induced due to the carelessness, or ignorance and lack of skilled. This error is also called operative error.
Limit test of chloride
Requirement: Apparatus- Nessler’s cylinder, pipette, stirring rod, beaker, stand.
Chemicals- Dilute nitric acid (10%) Silver nitrate(5%), test sample, standard sample(Sodium chloride)
. Chemical reactions Principle— The limit test of chloride is based upon the chemical reaction between the soluble chloride ion with a silver nitrate reagent in a nitric acid media. The insoluble silver chloride renders the test solution turbid (depending upon the amount of silver chloride formed and therefore, on the amount of chloride present in the substance under test. The turbidity is compared with the standard turbidity produced by the addition of silver nitrate, to the known amount of chloride ion (sodium chloride) solution. If the test solution shows less turbidity than the standard, the sample passes the test. Procedure: Test Standard Dissolve the test sample in water and transfer to the Nessler cylinder. Then add 1ml of dilute nitric acid and make the volume 50ml by adding water. Finally add 1ml of silver nitrate and stir immediately with stirring rod and set aside for 5 minutes. Observe the opalescence developed and compare with that of the test sample. 1ml of standard sample (0.05845% w/v) add in another cylinder. Then add the 10ml of nitric acid and make up the volume 50ml by adding water. Finally add 1ml of silver nitrate and stir immediately with stirring rod and set aside for 5 minutes. Observe the opalescence developed and compare with that of the standard sample.
Pharmaceutical analysis is the branch of medical chemistry that includes the series of experiment or procedures for purification, identification, determination, and quantitation, characterization, of any chemical compounds or components.
CHEMICAL/ Titrimetric METHODS
Volumetric analysis. ➢ Gravimetric analysis. ➢ Gasometric analysis
Complex metric titration.
This type of titration involves formation of complex during the titration and is used in the estimation of metal and also for their salts. The titrant used in this titration is usually called as ligands. EDTA is the most widely titrant used in the complex metric titration. EDTA(Ethylenediamine tetracetic acid or sodium edentate) is a very versatile complexing agent with greater water solubility and forms the most stable 1;1 ratio complexes with all metals except alkali metals such as sodium and potassium. The alkaline earth metal such as calcium and magnesium forms complexes which are unstable at low PH values and are titrated in ammonium chloride buffer at 10. The general equation for the titration— Mn+ + Na2EDTA → (MEDTA) n-4 + 2H+ Indicator used in the complex metric titration—the end point of the reaction is detected using an indicatory dye. The dye is added to the metal solution at the start of the titration, and forms a colored complex with small amount of the metal. The first drop of excess EDTA causes this complex to break up resulting in a color change. Example– Calcein, Eriochrome black T, curcumin, calcon, Murexide (ammonium purpurate), Hematoxylin, fast sulphon black etc. ➢ Titration with EDTA is used in the pharmacopoeial assaya of- calcium acetate, calcium chloride, calcium gluconate, magnesium carbonate, magnesium hydroxide, magnesium trisilicate, bismuthsubcarbonate, bacitracin Zinc, zinc chloride, zinc undecanoate.
Precipitation titration. A special type of titrimetric procedure involves the formation of precipitates during the course of titration. The titrant reacts with the analyte forming an insoluble product called precipitate. Thus, any titration in which the end product formed ot the completion of reaction is insoluble precipitate, this titration is called as ‘precipitation titration’. Precipitation is formed with rapid combination of two ionic (cation and anion) species to form very insoluble products. Methods of precipitation Titration— 1) Mohr’s method 2) Volhard’s method 3) Fajan’s method Mohr’s method—This method involves determination of the chloride ion concentration of a solution by titration with silver nitrate. In his method, silver nitrate solution is slowly added to chloride solution to produces a precipitate of silver chloride. Ag+ (aq) + Cl-(aq) → AgCl(s) When the entire chloride ion is precipitated, the excess of silver ions react with the chromate ions from potassium chromate which is the
Haematinics
Carbonyl iron.
➢ Chemical formula-Fe(CO)5 Molar mass-195.9g/mol ➢ Introduction— Carbonyl iron is a highly pure iron, prepared by chemical decomposition of purified iron pentacarbonyl. In pharmaceutics, carbonyl iron powder is used to treat iron deficiency and as an iron dietary supplement. ➢ Properties- Color and state— It is the pale yellow or straw color liquid. Odor and taste— It shows the pungent odor with metallic taste. Solubility—It is insoluble in water and ammonia, Soluble in organic solvents and slightly soluble in alcohol. ➢ Pharmaceutical preparation— pharmaceutically it is prepared in the form of- tablet, capsule, syrup, oral drop etc. ➢ Brand/Market Name—Irontic, Hefer-Z, Mycarb, Carvifol, Arfol-Z etc. Storage condition— It is stored in well closed air resistance unopened container and keep away from incompatible materials at room temperature and also away from the light and moisture. ➢ Uses/Applications— • Carbonyl iron is a supplements used to treat or prevent low blood levels of iron (such as those caused by anemia or pregnancy). • Iron helps your body produce red blood cells that carry oxygen through your blood to tissues and organs.
Antacids are meant for neutralizing the gastric PH in stomach by binding or inhibiting the gastric receptor in our stomach. It inhibits the extra hydrochloric acid secretion in stomach and neutralizes the increasing level of hydrochloric acid.
Classification of Antacids
On the basis of acting site it is divided into two categories— 1. H2-receptor antagonist— Cimetidine, Ranitidine, Femotidine. 2. Proton Pump Inhibitor— Esomeprazole, Omeprazole, Pantoprazole. On the basis of inorganic elemental nature it is divided into many categories— 1. Calcium containing antacids— Calcium carbonate, Tribasic calcium phosphate. 2. Magnesium containing antacids— Magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium trisilicate. 3. Aluminium containing antacids— Aluminium hydroxide, aluminium phosphate, aluminium carbonate, dihydroxy aluminium sodium carbonate. 4. Sodium containing antacids— Sodium bicarbonate. 5. Combined antacids— Aluminium hydroxide gel and Mg(OH)2. Aluminium hydroxide gel and Magnesium trisilicate. Aluminium hydroxide gel and calcium carbonate.
Antimicrobial are those agents which are prevents the growth of microorganisms (Bacteria, fungus, virus, parasites).
Classification of the antimicrobial agents— on the basis of their activity and chemical nature it is categories many parts— 1. Antibiotics agents— Those agent which is work against the bacterial infection. 2. Antifungal agents— Those agent which is work against the fungal infection. 3. Antiviral agents— Those agent which is work against the viral infection. 4. Antiparasitic agents— Those agent which is work against the parasitic infection.
Silver Nitrate. Chemical formula— AgNO3 Molar mass— 169.87g/mol. Introduction— Silver nitrate widely shows the antimicrobial or antiseptic properties. In the compound silver are attached to the nitrate by ionic bond, during the mechanism of action ionic bond break and release the free silver ions. These silver ions are binds to the tissue proteins of microbes and destroy the cellular activity.
Silver nitrate is prepared by the reaction of free silver with nitric acid. 3Ag + 4HNO3 → 3AgNO3 + 2H2O + NO. Properties— Color and state— it is a colorless crystalline powder or solid. Odor and taste— it is odorless and shows bitter metallic taste. Solubility— it is soluble in water and glycerol. Pharmaceutical preparation— Cream, gel, solution. Brand/Market Name— Silverex, Burn Heal, Sivacure+. Storage condition— It is stored in well closed air resistance unopened container and keeps away from incompatible materials (like copper) at room temperature, and also away from the light and moisture. It is very sensitive for heat and decomposes in their ionic form. Uses/Application— By precipitating the microbial surface protein it acts as an antibacterial and antiseptic characteristics. It is widely used a burning cream and cleaning agent. In the co-vid pandemic it is also used to manufacturing the sanitizer and cleaner preparation. Silver nitrate can also help create a scab to help stop bleeding from a minor skin wound. Ionic Silver. Chemical formula— Ag+ Molar mass— 107.868g/mol Introduction— Ionic silver is widely used in the manufacturing unit. Free silver ions are easily binds to the surface proteins of the microbes and forms the complexes/precipitate. Ionic silver are also used as the precursor for other metal extraction. Very dilute solutions of ionic silver act as an astringent and mildly antiseptic.
Dental products Classification
On the basis of their activity it is divided into five parts- 1. Antiplaque agent— Example: – Triclosan, delmiopinol, phenolic compounds 2. Anticaries agent—Example: – Sodium fluoride, stannous fluoride. 3. Cleaning/dentifrice agent —Example: – Calcium carbonate, calcium phosphate, sodium metaphosphate. 4. Desensitizing agent—Example: – Strontium chloride, zinc chloride. 5. Mouth washes—Example:- Chlorhexidine gluconate, potassium nitrate.
Calcium carbonate. Chemical formula— CaCO3 Molar mass—100.0869g/mol Introduction—.It is also known as aragonite, calcite, and limestone, marble. Calcium carbonate shows wide range of activity in our body by providing the calcium ion in our body. Teeth enamel is mainly made by calcium salts so calcium carbonate plays a major role in tooth development and provides the strength of tissues. Calcium ions are also used in the water treatment and agricultural aspects. Overdose of calcium cause the hypocalcaemia and digestive problems. • Calcium carbonate is prepared by the reaction of calcium oxide with water and carbon dioxide. Initially water is added to calcium oxide then it forms calcium hydroxide the carbon dioxide is passed through this solution to precipitate the desired calcium carbonate. Reaction- CaO + H2O → Ca(OH)2 Ca(OH)2 + CO2 → CaCO3↓ + H2O Properties— ➢ Color and state—it is the whitish or milky crystalline powder. ➢ Odor and taste—it is odorless with bitter taste. ➢ Solubility—it is practically insoluble in water and ethanol. Pharmaceutical preparation—Tablet, syrup, capsule, pills, Tooth paste, tooth powder, oral drop. Brand/Market Name— Coolwhite, Emoform, denti fresh etc. Storage condition—It is stored in well closed air resistance unopened container and keep away from incompatible materials at room temperature and also away from the light and moisture. Uses/Application— ➢ It is used for water treatment. In water treatment it forms the complexes with other harmful metals. ➢ Calcium plays a vital role for the growth and maturation of the body like muscles, bones, teeth, and organs.
Medicinal gas example
Oxygen
Chemical formula- O2. Molar mass: 32 g/mol Introduction – Oxygen are present in gases in the form of dioxygen with formula O2. Oxygen is the most abundant of all the elements on earth. Oxygen forms about 46.6% by mass of earth’s crust. Dry air contains 20.946% oxygen by volume. Naturally it is prepare by the green plants in the presence of light energy and it helps in our respiratory mechanism . In our body it is transported by the blood and participate in the metabolism. Oxygen is the most critical factor on the earth for most of the aerobics living organisms.
Laboratory it is prepared by: Hydrogen peroxide is readily decomposed into water and dioxygen by catalysts such as finely divided metals and manganese dioxide. 2H2O2(aq) heat 2H2O(l)+O2(g) 2KClO3 2KCl + 3O2 Industrially, dioxygen is obtained from air by first removing carbon dioxide and water vapour and then, the remaining gases are liquefied and fractionally distilled to give dinitrogen and dioxygen. Properties- It is colourless diatomic gas. It is odourless and tasteless. Solubility -it is eaisly soluble in the water. Uses/ Application- Oxygen is used in most of the surgical and emergency conditions to full the oxygen demand to body. In the COVID pandemic oxygen is most uses by the hospitals and nursing homes to treat the patients. Storage conditions- Oxygen are stored in the oxygen cylinder ( made by steel and aluminium alloys) at environmental conditions. Oxygen are very reactive towards the inflammable material so it is store away from inflammable material.