Pharmaceutical Analysis 1 Flashcards
(477 cards)
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PHARMACEUTICAL ANALYSIS 1
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Definition of Quality
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Quality is defined by ISO as the totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs.
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A product is considered of good quality if it complies with the established requirements and standards.
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Quality assurance and control are essential to ensure compliance with government regulations and industry standards.
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Levels of Organization for Quality Management
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Quality Management: Involves the assembly and management of all activities aimed at producing quality products by organizations.
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Good Laboratory Practice (GLP): Refers to the processes and conditions under which laboratory activities are planned
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performed
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Quality Assurance (QA): A systematic approach to ensure that products meet quality requirements through planned actions.
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Quality Assurance vs. Quality Control
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Quality Assurance: Focuses on the systematic actions necessary to provide confidence that a product will satisfy quality requirements
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including policy identification and regulatory compliance.
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Quality Control: Involves operational techniques and activities to ensure that products meet quality standards
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including testing and measuring materials.
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Quality Control Systems
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Importance of Quality Control
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Minimizes the risk of marketing unsafe products and ensures compliance with regulatory requirements.
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Guarantees product efficacy and reduces operating costs and losses.
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Enhances employee morale and motivates professionals to promote the product.
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Characteristics of Ideal Pharmaceutical Dosage Forms
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Each dosage unit must contain the exact amount of drug claimed on the label.
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The drug must be stable in its formulation and packaging for the expected shelf life.
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Dosage forms should be free from toxic foreign substances.
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Current Good Manufacturing Practices (CGMP)
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CGMP ensures that products are consistently produced and controlled to quality standards appropriate for their intended use
as recognized by WHO.
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Key components include sampling
specifications
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CGMP aims to prevent risks to patients from inadequate safety
quality
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ISO Standards and Certifications
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Overview of ISO Standards
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ISO 9001: Focuses on customer satisfaction and consistent quality products
promoting efficiency and continual improvement.
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ISO 14001: Addresses environmental impact
helping organizations monitor and control their operations' ecological footprint.
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ISO 45001: Pertains to occupational health and safety management
aiming to reduce workplace accidents and ensure compliance with safety legislation.
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Benefits of Working with Certified Manufacturers
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Reduces the risk of errors and enhances product quality.
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Promotes efficiency in product delivery and compliance with regulations.
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Improves corporate reputation and opens opportunities for cost savings.
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Defects in Pharmaceutical Products
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Understanding Defects
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A defect is an undesirable characteristic of a product that fails to conform to specifications
rendering it defective if it contains one or more defects.
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Defects can be classified based on measurability
seriousness
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Classification of Defects
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Variable Defects: Measurable defects such as length
width
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Attribute Defects: Non-measurable defects like color and odor that indicate nonconformance.
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Critical Defects: May endanger life or property
e.g.
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Types of Defects by Nature
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Ocular Defects: Visible defects such as foreign particulate contamination.
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Internal Defects: Not visible but present
e.g.
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Performance Defects: Issues with functionality
such as suppositories that do not melt at body temperature.
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Product Recall and Market Withdrawal
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Drug Recall Procedures
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The industry must correct production errors
while the government ensures adequate consumer protection measures are taken.
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Drug recalls are essential for maintaining public safety and trust in pharmaceutical products.
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Market Withdrawal vs. Stock Recovery
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Market Withdrawal: Involves the removal or correction of a product with minor violations that do not warrant legal action.
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Stock Recovery: Refers to the removal of products that have not yet been marketed or are still under the company's control.
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Reasons for Recall of Products
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Classifications of Product Recalls
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Class I: Products that pose a significant risk to health
including:
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Drugs that are dangerously defective
potentially leading to serious health issues or death.
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Foods containing botulinum toxin
which can cause severe illness.
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Label mix-ups on life-saving drugs
risking incorrect medication administration.
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Foods with undeclared allergens
posing serious allergic reactions.
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Presence of Salmonella in ready-to-eat foods
leading to foodborne illness.
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Class II: Products that may cause temporary health issues
such as:
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Drugs that are under strength
potentially ineffective for treatment.
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Sausages containing undeclared dry milk
risking allergic reactions.
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Foods contaminated with yeast or mold
which can cause gastrointestinal issues.
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Class III: Products with minimal risk
including:
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Situations where adverse health reactions are unlikely but violate FDA regulations.
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Minor defects in packaging or labeling
such as incorrect weight or volume.
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Non-organic products mislabeled as organic
misleading consumers.
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Implications of Product Recalls
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Product recalls can significantly impact consumer trust and brand reputation.
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Regulatory bodies like the FDA enforce strict guidelines to ensure consumer safety.
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Companies must have effective quality control systems to minimize recall risks.
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Recalls can lead to financial losses and legal consequences for manufacturers.
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Statistical Quality Control
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Overview of Statistical Quality Control
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Statistical Quality Control (SQC) involves using statistical methods to monitor and control production processes.
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Total Quality Management (TQM) emphasizes customer-driven quality standards and continuous improvement.
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SQC tools help identify quality problems in both production processes and final products.
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Categories of Statistical Quality Control
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1. Descriptive Statistics:
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Used to summarize and describe quality characteristics
including mean
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Control charts are employed to monitor production processes and ensure they remain within acceptable limits.
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2. Statistical Process Control (SPC):
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Involves inspecting random samples to determine if production processes are functioning correctly.
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Identifies quality issues during production
allowing for timely corrections.
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Control Charts
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Control charts graphically represent data to show whether a process is in control.
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They include upper control limits (UCL) and lower control limits (LCL) to define acceptable variation.
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A process is considered out of control if data points fall outside these limits.
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Sources of Variation in Quality Control
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Types of Variation
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Common Causes of Variation:
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Unavoidable variations due to slight differences in materials
processes
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These variations are inherent to the process and cannot be eliminated.
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Assignable Causes of Variation:
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Variations that can be identified and corrected
such as human error or poor-quality materials.
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Quality Control Charts
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Control Chart for Attributes:
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Measures quality characteristics that can be counted (e.g.
defects).
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Includes P-Charts (proportion of defective items) and C-Charts (count of defects per unit).
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Control Chart for Variables:
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Monitors measurable characteristics (e.g.
weight
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Includes Mean (x-bar) charts and Range (R) charts.
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Acceptance Sampling and Sampling Plans
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Acceptance Sampling
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Acceptance sampling involves inspecting a sample of goods to decide whether to accept the entire lot.
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The Acceptable Quality Level (AQL) defines the maximum percentage of defects acceptable to consumers.
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Producers' risk refers to the chance of rejecting a good batch
while consumers' risk is the chance of accepting a bad batch.
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Sampling Plans
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1. Square Root System:
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A method for determining sample sizes based on the total number of items in a lot.
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2. Government Sampling Plan:
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Developed by engineers in 1942
widely accepted in industry
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Analytical Chemistry
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Overview of Analytical Chemistry
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Analytical chemistry focuses on the composition of matter and the methods used to analyze it.
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It is divided into qualitative analysis (identifying components) and quantitative analysis (measuring amounts).
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Categories of Pharmaceutical Analytical Chemistry
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1. Based on Sample Size:
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Macro (0.1 g – 1 g)
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Semi-micro (0.01 g – 0.1 g)
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Micro (0.001 g – 0.01 g)
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Ultra-micro (< 1 mg).
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2. Based on Method Nature:
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Chemical methods (titrimetry
gravimetry)
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Analytical Procedures Overview
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Instrumental Methods
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Instrumental methods include techniques such as chromatography and spectrophotometry
which are essential for separating and quantifying chemical substances in a mixture.
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Chromatography involves the separation of components based on their movement through a stationary phase
while spectrophotometry measures the amount of light absorbed by a sample at specific wavelengths.
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Types of Determination
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Proximate analysis refers to the total amount of a group of substances
providing a broad overview of the sample's composition.
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Ultimate analysis focuses on the specific substances present
allowing for a more detailed understanding of the sample's chemical makeup.
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Characteristics of Analytical Procedures
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Accuracy: Refers to how close measurements are to the true or accepted value
crucial for reliable results.
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Precision: Indicates how close measurements are to each other
reflecting the consistency of the analytical method.
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Specificity: The ability to accurately measure the analyte in the presence of other components
ensuring that results are not skewed by interfering substances.
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Errors in Analysis
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Types of Errors
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Indeterminate Errors: Random errors that arise from slight variations in measurements
often difficult to detect and eliminate.
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Determinate Errors: Systematic errors that can be identified and corrected
often stemming from personal judgment
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Gross Errors: Major mistakes typically due to human error
easily recognized and usually result in the rejection of results.
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Quantitative Methods of Analysis
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Key Concepts in Titration
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Analyte: The chemical substance being analyzed
whose concentration is unknown.
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Titrant: A solution of known concentration used to react with the analyte
essential for determining the analyte's concentration through titration.
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Standardization: The process of determining the exact concentration of a volumetric solution
which can be achieved using primary or secondary standards.
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Titration Techniques
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Acidimetry: Titration of a base with a standard acid solution
commonly used in acid-base reactions.
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Alkalimetry: Titration of an acid with a standard alkali solution
also a vital technique in quantitative analysis.
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End Point: The point in titration where a noticeable change occurs
often indicated by a color change due to the use of indicators.
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Titrimetric Analysis Requirements
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Essential Requirements
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The reaction must be complete to ensure accurate results.
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An end point detecting device is necessary to identify when the titration is complete.
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The reaction should be rapid
allowing for efficient analysis without prolonged waiting times.
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Types of Titrations
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Direct Titration: Involves adding titrant directly to the analyte until the end point is reached.
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Residual or Back Titration: Used when the reaction is slow or does not yield a clear end point
involving excess titrant and a second standard solution for titration.
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Blank Titration: Conducted without the analyte to account for any errors in the reagents or procedure.
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Volumetric Apparatus and Cleaning Procedures
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Overview of Volumetric Apparatus
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Burettes can measure liquid volumes with precision up to 0.01 mL
making them essential for titrations.
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Pipets are designed to transfer specific volumes of liquid accurately
also to 0.01 mL.
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Volumetric flasks and graduated cylinders are used to contain and measure definite volumes of liquids.
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Cleaning Procedures for Volumetric Apparatus
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Cleaning is crucial to avoid contamination in volumetric analysis. Common cleaning solutions include:
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Sodium Dichromate in Sulfuric Acid: Effective for removing organic residues.
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Trisodium Phosphate: A mild cleaning agent suitable for general cleaning.
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Synthetic Detergent: Useful for routine cleaning of glassware.
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Chromic Acid: The official cleaning solution for burettes used in titration
known for its effectiveness.
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Formulas and Practice Problems in Volumetric Analysis
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Key Formulas Used
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Normality (N) is calculated using the formula: N = (grams of solute / (molecular weight x volume in L)).
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Equivalent weight can be calculated as: Equivalent weight = Molecular weight / n (number of H+ or OH- ions replaced).
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Practice Problems and Solutions
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Titration of NaOH with Potassium Biphthalate: Normality calculated as N = 4.9651 g / (0.20423 g/mol x 24.15 mL) = 1.00668 N.
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Normality of Sulfuric Acid: N(H2SO4) = (20.70 mL x 1.1055 N) / 22.5 mL = 1.01706 N.
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Calcium Hydroxide Neutralization: Weight of Ca(OH)2 in 100 mL = (19.5 mL x 0.1050 N x 0.03705 g) x 2 = 0.15171975 g.
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Neutralization Reactions
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Definition and Characteristics
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Neutralization reactions involve an acid reacting with a base to produce salt and water
represented as:
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General Reaction: Acid + Base → Salt + Water
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The resulting salt may be acidic or basic
affecting the pH of the solution.
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Types of Neutralization Reactions
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Aqueous Neutralization: Involves water as a solvent
using indicators like methyl red and phenolphthalein to determine endpoint.
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Non-Aqueous Neutralization: Utilizes organic solvents to enhance reaction sharpness and avoid water's interference.
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Indicators and Titration Methods
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Indicators Used in Titration
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Different indicators are used based on the pH range of the reaction:
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Methyl Red: pH 4.2-6.2
changes from red to yellow.
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Phenolphthalein: pH 8.0-10.0
colorless to pink.
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Titration Methods
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Acidimetry: Direct titration of acids with bases
using standard acids like hydrochloric acid.
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Alkalimetry: Direct titration of bases with acids
using standard alkaline solutions like sodium hydroxide.
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Acidimetry
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Overview of Acidimetry
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Acidimetry is a titration method used to determine the concentration of acids in a solution by neutralizing them with a base.
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It is particularly useful for analyzing weak bases and their salts
as well as various organic compounds.
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Common solvents used include neutral solvents like acetonitrile and acidic solvents such as glacial acetic acid.
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The method relies on standard solutions
indicators
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Standard Solutions in Acidimetry
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Perchloric acid in glacial acetic acid is the strongest common acid used
providing excellent results with weak bases.
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Standardization is achieved using potassium biphthalate as the primary standard
ensuring accuracy in titrations.
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Other standard solutions include dioxane and hydrogen bromide
which are also effective in acid-base reactions.
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Indicators Used in Acidimetry
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Different indicators are employed based on the strength of the base being titrated:
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For weak bases: Methyl rosaniline chloride
malachite green
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For stronger bases: Methyl red
methyl orange
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The choice of indicator is crucial for accurate titration results.
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Assays in Acidimetry
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Various compounds are analyzed using acidimetry
including:
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Albuterol
Atropine
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Sodium acetate and potassium citrate assays utilize visual indicators like crystal violet and Oracet blue
respectively.
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The assays help in determining the concentration of active ingredients in pharmaceutical formulations.
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Alkalimetry
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Overview of Alkalimetry
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Alkalimetry is the titration method used to determine the concentration of bases in a solution by neutralizing them with an acid.
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It is particularly effective for weakly basic compounds and is often performed in various solvent environments.
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The method employs standard solutions
indicators
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Solvents Used in Alkalimetry
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Acidic solvents like glacial acetic acid enhance the basicity of weak bases
making them more reactive in titrations.
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Basic solvents include ethylenediamine and n-butylamine
which are used for titrating medium-strength acidic substances.
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Neutral solvents such as acetone and tert-butyl alcohol are also utilized depending on the specific requirements of the titration.
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Standard Solutions in Alkalimetry
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Sodium methoxide is a common standard solution used in alkalimetry
providing a reliable base for titrations.
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Other examples include lithium methoxide and sodium aminomethoxide
which are used for specific assays.
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The choice of standard solution is critical for achieving accurate and reproducible results.
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Indicators Used in Alkalimetry
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Indicators for titration of strong acids include Azo violet and Thymol blue
which provide clear color changes at the endpoint.
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For weak acids
Thymolphthalein and 0-nitroaniline are commonly used
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The selection of indicators is essential for the success of the titration process.
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Precipitation Methods
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Overview of Precipitation Methods
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Precipitation methods involve the formation of insoluble substances or precipitates during titration.
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Key requirements include the formation and cessation of precipitates
as well as the development of turbidity in the solution.
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These methods are particularly useful for determining chloride ion content and other halides.
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Volhard Method
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Developed by Jacob Volhard in 1874
this method uses ferric ammonium sulfate as an indicator.
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The primary standard is sodium chloride
and standard solutions include 0.1 N silver nitrate and ammonium thiocyanate.
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It is effective for analyzing halides (Cl-
Br-
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Mohr Method
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Karl Friedrich Mohr's method is used for determining chloride ions in neutral or unbuffered solutions.
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Potassium chromate is the indicator
and the standard solution is 0.1 N silver nitrate.
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The titration must be conducted at a pH of 6.5 - 9 to ensure accurate results
as extreme pH can affect the reaction.
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Fajans Method
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This method analyzes halides using adsorption indicators like dichlorofluorescein and eosin Y.
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The endpoint is determined by changes in color of the silver halide precipitates
indicating the completion of the reaction.
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It is particularly useful for the assay of sodium chloride and other halide compounds.
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Complexation Methods and Oxidation-Reduction Methods
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Complexation Methods
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Complexation methods involve the quantitative analysis of inorganic pharmaceutical products containing polyvalent metal ions.
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EDTA (Ethylenediaminetetraacetic acid) is a key reagent that forms water-soluble complexes with metal ions
facilitating their analysis.
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Masking agents are used to prevent interference from other metals during titration
allowing for selective analysis.
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Indicators in Complexation Methods
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Metal-ion indicators such as hydroxynapthol blue and murexide are used to detect the presence of specific metal ions during titrations.
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The choice of indicator is crucial for achieving accurate results in complexometric titrations.
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Direct titration methods can be employed for various metal compounds
including calcium
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Oxidation-Reduction Methods
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Oxidation-reduction methods involve changes in the valence of reacting substances
with oxidation representing the loss of electrons and reduction the gain of electrons.
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These methods are essential for analyzing substances that undergo redox reactions
providing insights into their chemical behavior.
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Understanding the principles of oxidation and reduction is fundamental for successful titration in this category.
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Overview of Titration Methods
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Key Titration Methods
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Titration is a quantitative chemical analysis method used to determine the concentration of an identified analyte.
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Common methods include Permanganate Titration
Ceric Sulfate Titration
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Each method utilizes specific indicators and standard solutions to achieve accurate results.
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Standard Solutions and Indicators
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Standard solutions are solutions of known concentration used in titrations.
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Indicators are substances that change color at a particular pH level or concentration
signaling the end point of the titration.
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Common indicators include starch for iodine titrations and ferroin for ceric sulfate titrations.
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Permanganate Titration (Permanganometry)
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Characteristics of Permanganate Titration
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Potassium permanganate (KMnO4) is a strong oxidizing agent used in acidic solutions
where it is reduced to colorless Mn2+ ions.
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A slight excess of permanganate imparts a distinct pink color to the solution
indicating the end point of the titration.
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Applications of Permanganate Titration
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Used in direct and indirect titrations for various assays
including malic acid in cherry juice and hydrogen peroxide.
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Residual titration methods can be applied to determine the concentration of manganese dioxide and titanium dioxide.
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Example of Permanganate Titration
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Assay of Cherry Juice for Malic Acid: The juice is titrated with KMnO4 until a persistent pink color appears
indicating the end point.
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Assay of Hydrogen Peroxide: The reaction involves the reduction of permanganate
with the endpoint marked by a color
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Ceric Sulfate Titration (Cerimetry)
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Overview of Ceric Sulfate Titration
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Ceric sulfate in diluted sulfuric acid is a strong oxidizing agent
more stable than permanganate solutions.
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Sulfuric acid prevents hydrolysis and precipitation of basic salts
ensuring accurate titration results.
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Applications of Ceric Sulfate Titration
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Commonly used to assay ferrous sulfate tablets and ferrous fumarate
which react quantitatively with oxalate and arsenite ions.
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The end point is indicated by the formation of a red-colored complex with ferroin.
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Advantages of Ceric Sulfate Titration
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The solution remains stable even at boiling temperatures
making it suitable for various assays.
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Provides reliable results for compounds that may not react well with other titrants.
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Iodine Titration
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Iodimetry and Iodometry
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Iodimetry involves the direct titration of reducing agents with iodine
while iodometry involves the titration of oxidizing agents with thiosulfate after reacting with excess iodide.
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Starch is used as an indicator
changing color at the end point from colorless to dark blue.
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Applications of Iodine Titration
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Used to assay various compounds
including ascorbic acid
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The end point is visually detected by the disappearance of the blue starch-iodine complex.
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Example of Iodine Titration
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Assay of Ascorbic Acid: The sample is titrated with iodine until the blue color appears
indicating the presence of excess iodine.
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Assay of Selenium Sulfide: Similar methodology is applied
with starch as the indicator.
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Bromine and Potassium Iodate Titration
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Bromine Titration
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Bromine is used as an oxidizing agent in place of iodine for compounds like aniline and phenol.
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The end point is marked by the disappearance of the blue-black starch-iodine complex.
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Potassium Iodate Titration
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Potassium iodate serves as an oxidizing agent for the assay of potassium iodides and other reducing agents.
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The end point is indicated by a dark-blue colored solution due to the starch-iodine complex.
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Practice Problems and Calculations
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Example Calculations
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Normality Calculation: For sodium carbonate
the normality is calculated using the formula: N = Weight / (Volume x milliequivalent weight).
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Purity Determination: The percent purity of a sample can be calculated using the formula: % Purity = (V x N x meq.wt) / Weight (grams) x 100.
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Practice Problems
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1. Calculate the actual normality of sodium carbonate using titration data.
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2. Determine the normality of NaOH solution based on titration with sulfuric acid.
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3. Calculate the percent Mg(OH)2 in a sample using titration results.
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Titration Calculations and Purity Determination
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Key Concepts of Titration
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Titration is a quantitative chemical analysis method used to determine the concentration of an identified analyte.
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Involves the gradual addition of a titrant to a solution containing the analyte until the reaction reaches completion
indicated by a color change or a specific endpoint.
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Normality (N) is a measure of concentration equivalent to molarity but accounts for the reactive capacity of the solute.
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Purity Calculations
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The formula for calculating % purity is given by: % purity = (V x N x meq.wt / weight of sample) x 100.
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Example: For a sample weighing 0.2182 g
the purity calculation involves subtracting the contributions from different titrants used in the titration process.
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The purity of a sample can also be calculated using the volume of titrant consumed and its normality
as shown in the examples provided.
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Example Calculations
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For calcium carbonate in chalk: % purity = (16.7 mL x 0.1150 M x 0.05004 g / 0.2545 g) x 100 = 37.76%.
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Sodium oxalate example: N = (% purity/100) x (weight of sample) / (Volume x meq.wt) = 0.0954 N.
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Arsenic trioxide example: % purity = (23.4 mL x 0.1055 N x 0.04946 g / 0.1350 g) x 100 = 90.44%.
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Gravimetric Analysis Techniques
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Overview of Gravimetric Analysis
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Gravimetric analysis involves measuring the mass of an analyte or its derivative to determine its concentration in a sample.
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It is based on the principle that the mass of a substance can be accurately measured
providing a direct measurement of the analyte's quantity.
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Key Calculations in Gravimetric Analysis
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The % sulfur in sodium sulfate can be calculated using the formula: % Sulfur = (Wt of Precipitate x MW(S) / MW(precipitate) / Weight of the sample) x 100.
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Example: For a sample yielding 0.9000 g of barium sulfate
the % sulfur is calculated as 6.87%.
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The % chloride in a sample can be calculated similarly
using the mass of AgCl obtained.
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Example Problems
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For soluble chloride: % Cl = (0.7261 g x 35.45 g / 143.32 g / 0.3056 g) x 100 = 58.77%.
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For potassium iodide: % purity = (0.715 g x 166.0028 g / 234.77 g / 0.4600 g) x 100 = 109.91%.
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For impure chloride: % Cl = (0.9805 g x 35.45 g / 143.32 g / 0.7011 g) x 100 = 34.59%.
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Special Methods in Analytical Chemistry
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Ash Content Determination
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Total Ash: Residue remaining after incineration
composed of inorganic salts and impurities.
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Residue on Ignition/Sulphated Ash: Measures inorganic impurities after treating ash with sulfuric acid.
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Loss on Ignition: Determines the percentage of material that volatilizes under specified conditions.
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Acid Insoluble Ash
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Acid insoluble ash is the portion of total ash that does not dissolve in diluted hydrochloric acid.
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The process involves boiling the ash with HCl
which dissolves soluble components
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This method is crucial for assessing the purity of organic substances by quantifying inorganic residues.
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Ash Content Determination
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Importance of Temperature in Ash Determination
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Temperature is a critical factor in the process of ash determination
influencing the accuracy and reliability of results.
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Temperature Ranges: Different heat levels correspond to specific color indicators
which are essential for proper ash analysis:
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Very dull red heat: 500 to 550 °C
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Dull red heat: 550 to 700 °C
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Bright red heat: 800 to 1000 °C
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Yellow red heat: 1000 to 1200 °C
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White heat: 1200 to 1600 °C
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Formulas for Ash Content Calculation
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The determination of ash content involves several calculations based on the weight of the residue after incineration and treatment with acids.
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Total Ash Calculation:
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Formula: % Total Ash = (Weight of residue after incineration / Weight of substance) x 100
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Sulphated Ash Calculation:
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Formula: % Sulphated Ash = (Weight of residue after incineration with sulfuric acid / Weight of substance) x 100
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Acid-Insoluble Ash Calculation:
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Formula: % Acid-Insoluble Ash = (Weight of residue after treatment with diluted HCl / Weight of sample) x 100
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Loss on Ignition (LOI):
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Formula: % Loss on Ignition = (Weight of sample - Weight after ignition) / Weight of sample x 100
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Practice Problems for Ash Content
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Practice problems help reinforce the understanding of ash content calculations.
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Problem 1: Given weights for crucibles and samples
calculate % Moisture and % Total Ash.
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Problem 2: Calculate % Total Ash from a residue of 0.1185 g from a 7.60 g sample.
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Problem 3: Compute % Loss on Ignition for magnesium sulfate with a sample weight of 3.20 g yielding a residue of 2.15 g.
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Sample Data Table:
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Sample No.
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Weight of Crucible (g)
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Weight of Crucible + Sample (g)
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Weight of Sample After Incineration (g)
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% Total Ash
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1
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16.4896
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16.6303
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0.0005
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0.0036
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2
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27.0679
432
27.2376
433
0.0446
434
0.26280000000000003
435
436
3
437
28.1779
438
28.365
439
0.0101
440
0.054000000000000006
441
442
443
Water Content Determination
444
Karl Fischer Method Details
445
The Karl Fischer method is a precise technique for measuring water content in various substances.
446
Components of Karl Fischer Reagent: Consists of sulfur dioxide
iodine
447
Water Equivalence Factor (f): Represents the milligrams of water equivalent to 1 mL of Karl Fischer reagent.
448
Direct Titration Formula: % Water Content = (S x f / Weight of substance) x 100
where S is the volume of the reagent used.
449
Practice Problems for Water Content
450
Practice problems enhance understanding of water content calculations using the Karl Fischer method.
451
Problem 1: Calculate the water content of Streptomycin powder using a 3.50 g sample with a water equivalence factor of 4.6 and a volume of 9.2 mL consumed.
452
Problem 2: Calculate the water content of an antibiotic powder using a 360 mg sample and a volume of 10.1 mL of KF reagent with a water equivalence factor of 4.7.
453
Introduction to Extractives and Crude Fiber
454
Soxhlet Extraction Method
455
The Soxhlet apparatus is a key tool for extracting compounds from solid materials using volatile solvents.
456
It allows for continuous extraction
maximizing yield from small quantities of drug samples.
457
This method is particularly useful for extracting lipophilic compounds
enhancing the analysis of drug efficacy.
458
459
460
Calculation of Extractive Content
461
The formula for calculating extractive percentage is:
462
% Extractive = (Weight of extractives / Weight of crude drug) x 100.
463
Example calculation: If 0.9155 g of extractive is obtained from 27.5820 g of crude drug
the extractive percentage is 3.32%.
464
This calculation is vital for determining the quality and potency of herbal medicines.
465
Analysis of Oil Properties
466
Acid Value
467
Acid value indicates the number of milligrams of KOH needed to neutralize free acids in 1 g of oil
fat
468
It serves as a general indicator of the condition and edibility of oils
with higher values indicating poorer quality.
469
Example: Canola oil has an acid value of 0.071
while used frying oil has a significantly higher value of 31.0
470
Saponification Value
471
Saponification value measures the milligrams of KOH required to saponify esters and neutralize free acids in 1 g of oil.
472
It is used to check for adulteration in oils
with higher values indicating a greater capacity for soap production.
473
Example calculation: For cottonseed oil
the saponification value is calculated as 192.39 based on titration results.
474
Ester Value
475
Ester value is the number of milligrams of KOH required to saponify esters in 1 g of oil
with the relationship EV = SV - AV when free acids are present.
476
It provides insight into the composition of oils
particularly in distinguishing between free acids and esters.
477
Example: For beeswax with an acid value of 20.4 and a saponification value of 89.8
the ester value is 69.4.
