Pharmaceutical Analysis

• Pharmaceutical Analysis involves identifying, determining, quantifying, and purifying substances.
• It uses manual, chemical, and instrumental methods.
• Qualitative analysis identifies and purifies substances in a sample, pinpointing functional groups or elements
• Quantitative analysis determines the amount and concentration of substances or the amount of solute in a solution.
• Semi-quantitative analysis determines if an impurity is above or below a specified limit, related to limit tests.

Scope of Analysis

• Pharmaceutical analysis ensures effective, safe, and pure drugs in production and quality control.
• Quality Control evaluates raw materials, intermediates, and finished products.
• It identifies compounds to detect the presence or absence of components in a drug.
• It determines the amount of impurities and pure components.
• Analysis is used in farming to know the amount of essential nutrients for plant growth.
• Diagnosis is done to identify the cause of illnesses, food determination, biological sample determination, dairy product analysis, forensic science, soil studies, and research.
• Instrumental and non-instrumental methods are used.
• Instrumental methods use instruments for analysis and are further divided into several types.
• Non-instrumental methods, also known as classical methods, are not used for sample analysis and involve titrations and chemicals like Titration & Gravimetry

Methods of Expressing Concentration

• Methods are used to find the drug concentration or amount in a solution.
• Concentration is the amount of solute mixed with a solvent.
• Molarity (M) expresses concentration as moles of solute per liter of solution.
• Molality expresses concentration as moles of solute per kilogram of solvent.
• Normality (N) expresses concentration as the number of gram equivalents of solute per liter of solution.
• Formality expresses concentration as the number of formula weights per liter.
• Mole fraction and mole percentage.
• Percentage calculation.
• Parts per million (ppm).

Molarity

• Also known as molar concentration, denoted by 'M'.
• It is the number of moles of solute dissolved in one liter of solution.
• Unit is mol/L.
• Mole is the fundamental unit to measure the amount of a substance (solute).
• mole = mass given / molecular weight.

Molality

• Also known as molal concentration and denoted by 'm'.
• It is defined as the number of moles of solute dissolved in one kg of solvent.
• M = No. of moles of solute / weight of solvent (in kg).

Normality

• Also known as Normal Concentration, denoted by capital 'N'.
• It is the number of gram equivalents of solute dissolved per liter of solution.
• N = No. of gram equivalent / volume of solution (in L).
• Gram Equivalent = Molecular weight / [Acidity/Basicity].

Formality

• Gram formula weight of solute dissolved in one liter of solution for ionic compounds.

Percentage Calculation

• Also known as 'percentage concentration'.
• % by weight of solute: % w/w = (weight of solute / weight of solution) x 100.
• % by volume of solute: % v/v = (volume of solute / volume of solution) x 100.
• % of weight of solute by volume of solution: % w/v = (weight of solute / volume of solution) x 100.

Mole Fraction

• It is defined as the ratio of moles of solute to the total moles of solute and solvent.
• Xsolute = moles of solute / (moles of solute + moles of solvent).
• Mole percentage = Mole fraction x 100.

Parts per Million

• Refers to the parts of solute in one million parts of solution.
• ppm = (mass of solute / mass of solution) x 10^6.
• It is used for very less quantity concentration substances.

Standard Solutions

• solutions with accurately known concentrations, pure and use for standardization.
• Standardization makes solutions standard.

Primary Standards

• Prepared with highly pure reagents or chemicals and have accurately known concentrations.
• They do not need further standardization.
• Properties: highly pure, less reactive, stable, soluble, non-toxic and environmentally friendly.
• Examples: Sodium Carbonate, oxalic acid, silver nitrate.

Secondary Standards

• Solutions less stable than primary standards, standardization is done with primary standard solutions.
• Used for quantitative analysis and standardization of other substances.
• Properties: less pure, more reactive, less stable.
• Examples: Sulphuric acid (H2SO4), Potassium permanganate (KMnO4), HCl (Hydrochloric acid).

Preparation of Molar and Normal Solutions

• Preparation is the process of dissolving pre-weighed standard solutes/drugs in a solvent.
• Normal solution normality, . "Car.eq/vo. of Cam -Preparation of Standard Solution

Sodium Hydroxide (NaOH)

• Molecular weight is 40g/mol, with an acidity of 1.
• For 0.1M: dissolve approximately 4g NaOH in 1000 ml of solution.
• Standardize through titration with potassium biphthalate, using phenolphthalein indicator until pink color indicates the endpoint.
• IN = 40g in 1000 ml.

Hydrochloric Acid (HCl)

• Molecular weight is 36.46 g/ml, with a basicity of 1.
• Preparation: Add 8.5 ml of concentrated HCl solution to 1000 ml of distilled water.
• Standardize using THAM, bromocresol indicator with pale yellow endpoint.
• Standardization for 0.1N HCl: Using 5ml of 0.1 N of sodium carbonate, with methyl orange indicator.

Sodium Thiosulphate

• Molecular weight is 248.18.
• For 0.1 M: dissolve 250gm of sodium thiosulphate in 1000 ml of distilled water.
• Standardize using potassium iodate.

Sulphuric Acid (H2SO4)

• Molecular weight is 98g, with a basicity of 2.
• Add 6ml of H2SO4 into 1000 ml of water.
• Standardize using Sodium carbonate solution and methyl red indicator.

Errors

• Errors is the define as it is the difference between the standard(true) value to the observed valve.

Sources of Errors

• Improper sampling or sample preparation.
• Errors caused by the analyst due to lack of knowledge and focus.
• Improper calibration in equipments.
• Incorrect observation and data.
• Wrong Calculation.
• In Sample.
• Wrong Method Selection.

Minimizing errors

• Can be minimized by following methods
• Calibration of Instruments or Apparatus.
• Can be minimized by the calibration of instruments and apparatus(glassware etc.)

Significant Figures

• Used to express observations and results, mainly based on the decimal system, defining the degree of accuracy.
• All non-zero digits are significant.

Rounding off Digits

• Required when an answer in a fixed number of digits is needed, which increases from 2.45689 to 2.4569to 2.457