Quantitative chem Flashcards
Defined as the application of quantitative analytical chemistry…
- To the analysis & determination of the purity and quality of drugs & chemicals used in pharmacy.
- To the analysis & determination of the chemical constituents found in the human body whose altered concentration during disease states serve as diagnostic aids in the practice of medicines.
- To the analysis of medicinal agents and their metabolities found in biological systems
QUANTITATIVE PHARM CHEM
importance
1.) Pharmacists must have the knowledge to advise medical practitioners on drug quality
2.) Pharmacist must alert health professionals to the influence which drugs may have on clinical laboratory methods.
3.) Pharmacists must monitor drug levels during therapy.
In case the quality of a drug product is questioned by a physician, a pharmacist is:
Responsible for initiating steps to determine if a product is defective:
- Calling and advising the drug manufacturer of the problem involving the product
- Analyzing the preparation in the prescription laboratory, borrowing needed equipment from a clinical laboratory
- Sending a portion of the sample to a private laboratory for analysis
MANIFESTATION OF A DEFECTIVE PRODUCT
- Improper Labeling
- Discoloration
- Presence of Cloudiness
- Presence of Crystals
- Presence of Precipitates
“Sum of all factors” which contribute directly or indirectly to the safety, effectiveness, and reliability of the product.
QUALITY
Refers to the “sum of all procedures” undertaken to ensure the identity and purity of a particular pharmaceutical.
Such procedures may range from the performance of single chemical experiments which determine the identity and ________ for the presence of particular pharmaceutical substance (thin layer chromatography, infrared spectroscopy, etc) to more complicated requirements of pharmacopoeial monographs.
QUALITY CONTROL
Quality control guarantees within resonance limits that a drug product:
- Is free of impurities.
- Is physically and chemically stable.
- Contains the amount of active ingredients as stated on the label.
- Provides optimal release of active ingredients when the product is administered.
REFERENCE BOOKS ON DRUG STANDARDS
British Pharmacopoeia
United States Pharmacopoeia
National Formulary
Homeopathic Pharmacopoeia of the United States
International Pharmacopoeia
From Great Britain
Product of merging by the 3 cities’ pharmacopoeia of London, Edinburgh, and Dublin in 1864
British Pharmacopoeia
1st American Pharmacopoeia, 1778
Lititz pharmacopoeia
Suggested to the medical society of NY the pharmacopoeia.
Father of USP
Dr. Lyman Spalding (January 6, 1817)
Exclusive for doctors, held every 10 years (revise USP)
In 1940, pharmacies invited and revised and updated USP every 5 years.
USP convention
Used to be a revolt/rebellious records coined as the NF of the unofficial preparations.
June 30, 1906: changed to National Formulary
National Formulary
Declared USP & NF as standards for medicinal and pharmaceutical substances.
President Theodore Roosevelt
Coined by Samuel Hahnemann
Principle: like cures like or the law of similarities (vaccines/immunizations)
Homeopathic Pharmacopoeia of the United States
Homeopathic Pharmacopoeia of the United States is coined by
Samuel Hahnemann
Published by WHO
Recommendation to national pharmacopoeia revisions
International Pharmacopoeia
First American pharmacopoeia, Lititz Pharmacopoeia, was published for use by the military hospital of the United States Army
1778
Massachusetts Medical Society published a 272-page pharmacopoeia containing information on monographs on 536 drugs and pharmaceutical preparations.
1808
Lyman Spalding submitted a plan to the medical society of the country of New York for the creation of national pharmacopoeia. He was recognized as the father of USP.
January 6, 1817 (submitted)
Draft pharmacopoeias were reviewed, consolidated, and adopted by the 1st USP convention assembled in Washington, DC.
January 1, 1820 (reviewed, consolidated, adopted)
The first USP was published in English and Latin.
December 15, 1820 (published)
The first edition of the National Formulary of unofficial preparations was published.
1888
The pharmacopoeial convention granted authority to issue supplements to the USP to maintain satisfactory standards.
1900
The title National Formulary of Unofficial Preparations was changed to National Formulary (NF).
President Roosevelt signed into law the First Federal Pure Food and Drug Act, designating both the USP and NF as establishing legal standards for medicinal and pharmaceutical substances.
June 30, 1906
Convention decided to revise the USP every 5 years while maintaining the use of periodic supplements. The NF was revised every 10 years.
1940
The USP Convention Inc. purchased the NF, unifying the unofficial compendia and providing the mechanism for a single national compendium.
1975
The first combined compendium, compromising the USP XX and NF XV, became official.
July 1, 1980
The USP 23 – National Formulary 18 was the first edition to drop the use of Roman numerals, in favor of Arabic numerals to indicate the edition.
1995
The USP-NF became an annual publication.
2002
METHODS OF ANALYSIS
- Volumetric Analysis
- Physicochemical Analysis
- Gravimetric Analysis
- Special Methods
Determination of the volume of a solution of known concentration required to react with a given amount of the substance to be analyzed.
Volumetric Analysis
Based on some physical or chemical property/properties of the substance being analyzed.
Physicochemical Analysis
Employ instrumental techniques of physicochemical analysis
o Cinematographic
o Spectrophotometric
o Electrometric
o Thermal conductimetric
o Refractometric
o polarimetric
Separation by extraction, precipitation, and other means of the constituent to be determined either in the natural state or in the form of definite compound the composition and of which is known to the analyst, and the weighing of the resulting product.
Gravimetric Analysis
Those which requires a distinct type of technique.
Ex: alkaloid assaying, saponification value, acid value
Special Methods
Used to denote the agreement of an experimental result or the agreement of the mean value of the experimental results with the hue value.
ACCURACY
Measure of reproducibility of date within a series of results.
PRECISION
The discrepancies in the results are caused by various sources of error to which all experimental data are subject.
Source and Nature of Errors
2 types of errors
Indeterminate errors
Determinate errors
Manifest themselves by slight variations in a series of observations made by the same observer under identical conditions.
Causes are difficult to detect such as the differences in the judgement and the skill of the analyst.
Indeterminate errors are intangible, and their elimination by the analyst is impossible.
Indeterminate Errors
Nature that occurs in constant manner in each series of determinations.
usually detectable and so may be eliminated
Arise from causes such as:
- Personal error made by the analyst (ex. Inability to judge color changes sharply).
- Errors of method caused by faulty procedure (ex. Incorrect sampling, contamination of precipitates, and improper selection of indicators).
- Apparatus errors due to poor construction or calibration (ex. Inaccuracy in the calibration of burets or pipets, inequality in the length of the arms of the balance and incorrect weights).
Determinate Errors
_______ and __________ burets are used to deliver accurate volumes of solutions in titrations.
Geissler (Acid)
Mohr (Base)
Prior to use, burets are cleaned with detergent solutions followed by rinsing with distilled water and finally, with __________ of the solution to be measured.
three times 5-mL portion
TITRATION SET-UP
- Geissler (Acid) Buret
- Mohr (Base) Buret
- Buret Clamp
- Iron Stand
- Erlenmeyer Flask
chemical substance being analyzed.
analyte or active constituent
solution of known concentration
titrant
slow addition of one solution of a known concentration (called a titrant) to a known volume of another solution of unknown concentration until the reaction reaches neutralization, which is often indicated by a color change.
titration
Theoretical point at which equivalent amounts of analyte and titrant have reacted.
EQUIVALENCE POINT or STOICHIOMETRIC POINT
Point at which there occurs a sudden change in some property of the reaction mixture.
END POINT
Determination of the normality or molarity of a solution.
STANDARDIZATION
Concentration expression and defined as the number of equivalents of solute per liter or milliequivalents per milliliter of a solution.
NORMALITY
An expression of the concentration of a solution in terms of moles per liter.
MOLARITY
Solution of known normality or molarity.
STANDARD SOLUTION
A highly purified – about 99.99% (ultrapure) compound that serves as reference material in titration.
PRIMARY STANDARD
A compound whose purity (97-98%) has been established by careful chemical analysis.
SECONDARY STANDARD
Sometimes it is necessary to add an excess of the standard titrant and the excess amount is titrated with a second standard titrant.
BACK TITRATION
The difference in volume and mass between the end point and equivalence point.
TITRATION ERROR
Chemical which changes color at or very near the equivalence point.
Indicators are also very weak acids and bases.
o In acidic conditions, the color of the acid forms (HlN) predominates.
o In alkaline conditions, the color of conjugate base (lN) predominates.
INDICATOR
complex compounds used
- To determine the end point in neutralization process.
- To determine hydrogen ion concentration (H+) of pH.
- To indicate that a desired change in pH has been affected.
indicator
thymol blue
Red Yellow 1.2 – 2.8
bromophenol blue
Yellow Violet 3.0 – 4.6
methyl orange
Orange Yellow 3.1 – 4.4
methyl red
Red Yellow 4.2 – 6.3
chlorophenol blue
Yellow Blue 4.8 – 6.4
bromothymol blue
Yellow Blue 6.0 – 7.6
cresol red
Yellow Red 7.2 – 8.8
phenolphthalein
Colorless Red 8.3 – 10.0
TYPES OF TITRATIONS
- DIRECT TITRATIONS
- RESIDUAL (BACK TITRATION)
- INDIRECT TITRATION
* Blank Titration
Direct addition of a titrant to analyte.
- DIRECT TITRATIONS
Adding excess amount of acid to a base to quantify with base.
- RESIDUAL (BACK TITRATION)
Needs to perform pre-treatment before titration.
- INDIRECT TITRATION
correcting errors, repeating the assay without the analyte.
- Blank Titration
Chemical processes in which an acid (proton donor) reacts with a base (proton acceptor), the product of a neutralization reaction in aqueous solution are water and salt.
neutralization reactions
2 types of titrations
Alkalimetry - BASE
Acidimetry - ACID
