11438 - Drug Analysis II (GR.B)

Learning outcomes

At the end of the course, which also includes laboratory activity, the student will have knowledge of the methods of quantitative analysis both volumetric and instrumental, as reported in the monographs of the European Pharmacopoeia (Ph. Eur) and Italian Official Pharmacopoeia (FUI), and related to the determination of the purity of raw materials as well as to that of the content of active ingredients in pharmaceuticals. In particular, the student is able: - to apply the knowledge to real problems (quantitative analysis and quality control of pharmaceuticals) – to suggest alternative analytical methods compared to the official methods, by rationally motivating the selected approaches on the basis of the achieved ability.

Course contents

INTRODUCTION. Chemical equilibrium and concepts of solubility, ionic strength, activity, activity coefficient, concentration.

VOLUMETRIC ANALYSIS. General information on Equivalence and titration reactions. Practical aspects in volumetric analysis: instrumentation and laboratory glassware.
-Acid - base titrations: titration curves of acids and bases. Determination of the end point of the titration: acid-base indicators. Practical aspects: primary standards and applications. Acid - base titration in aqueous-organic solvents.
-Acid – base titrations in non-aqueous medium: autoprotolysis and acid - base solvents; dielectric constant. Equilibria in glacial acetic acid and titration of weak bases with examples by the pharmacopoeias; titration of weak acids in non-aqueous medium with examples by the pharmacopoeias.
-Precipitation titrations: Titration curves. Argentometric methods (Mohr, Fajans, Volhard methods). Applications.
-Complex-formation titrations: EDTA titrations. Influence of pH on EDTA ionization and complexation constants.  Indicators for EDTA titrations; applications (direct titrations; back-titrations; substitution titrations).
-Redox titrations: Overview of oxidizing and reducing agents. Scale of redox potentials and Nernst equation. Redox titration curves and applications.

ELECTROCHEMICAL METHODS OF ANALYSIS:
-Potentiometry. General principles, electrodes and definition of standard reduction potentials. Electrochemical cells as analytical probes. Most common electrodes: reference electrodes and measurement electrodes. Glass electrode for pH measuring and other selective electrodes. Potentiometric titrations and examples of applications of the pharmacopoeias.
-Amperometric titrations: Definitions. Amperometric titrations with two measurement electrodes (for diazotization titrations and Karl - Fisher titration).
-Polarography and voltammetry: theoretical principles and applications.
-Conductimetry: Theoretical principles on the conductivity of electrolytes. Conductivity cell. Conductimetric titrations: examples of applications.

QUANTITATIVE ANALYSIS BY UV-vis SPECTROPHOTOMETRY.
-Spectrophotometric analysis in UV-vis range. Theoretical principles of UV-vis absorption. Beer-Lambert law. Instrumentation: single and double beam spectrophotometers. Applications: analysis of binary mixtures and derivatization. Applications to the analysis of drugs and examples by the pharmacopoeias. 
-Solid-Liquid (S/L) extraction: general principle and application to the sample preparation in UV-vis analysis. Supercritical fluid S/L extraction.

CAPILLARY ELECTROPHORESIS: general principle and instrumentation. Parameters affecting separation of charged molecules (pH, ionic strength, nature of background electrolyte). Electro-osmotic flow. Micellar electrokinetic chromatography (MEKC) and its applications in pharmaceutical analysis.

SAFETY IN LABORATORY: Behavior in lab and risks arising from handling chemicals.

LABORATORY ACTIVITY
-Acid-base titrations: standardization of sodium hydroxide and hydrochloric acid and purity determination of various compounds according to the pharmacopoeias.
-Acid-base titrations in non-aqueous media of weak acids, weak bases and salts (hydrochlorides) according to the pharmacopoeias.
-Potentiometric titration of phosphoric acid.
-Conductimetric titrations (sodium acetate).
-Precipitation titrations (argentometric methods)
-Redox titrations using permanganate, iodine/iodide etc.
-Complex-formation titrations with EDTA.
-Amperometric titration of sulfonamides
-UV-vis spectrophotometry in quantitative analysis: Evaluation of linear response Absorbance / concentration for compounds of pharmaceutical interest. Quantitation by calibration curves of active ingredients in pharmaceuticals.

Readings/Bibliography

1) V. CAVRINI, V. ANDRISANO, Principî di analisi farmaceutica, Ed. Esculapio, Bologna, prima edizione 2013.
2) HARRIS, Chimica analitica quantitativa, Ed. Zanichelli, 2005.
3) Slides from lessons.
4) Lecture notes available by AMS campus (necessary for the lab activity).

Teaching methods

The theoretical lessons are intended to provide the basic knowledge of quantitative pharmaceutical analysis by titrimetry and instrumental methods. In the laboratory activity the students will apply analytical procedures for the quantitation of raw materials and active ingredients in pharmaceuticals.

Assessment methods

The learning assessment should evaluate the achievement of the objects of teaching, specifically:

- Knowledge of the chemical and physico-chemical methods of quantitative analysis, as well as the acquisition of the practical ability necessary for the correct solution of various analytical problems;
- The ability to apply the achieved theoretical and practical knowledge, at the determination of the purity of active ingredients and quality control of commercial formulations;
- The ability to critically discuss and apply the analytical methods reported in the Italian Official Pharmacopoeia and European Pharmacopoeia for quantitation of drugs and purity determination.
The assessment is evaluated by means of laboratory practice test, to be carried out at the end of the lab activity, and final oral examination. The lab practice test has to be passed before oral examination.

The final grade will be established by evaluating the student performance on both lab activity and oral examination. The latter will consists in 3-4 questions also involving exercises, calculations etc..

Teaching tools

The theoretical lessons will be held by using slides.

The lab activity will be carried out in laboratories equipped with specific reagents and analytical instrumentation suitable for the drug quality control.

Office hours

See the website of Roberto Gotti