LABORATORY OF DRUG ANALYSIS II A - L

The course, consisting in class lectures and lab practice, is intended to give knowledge of classic techniques for quantitative analysis and quality control of pharmaceuticals. During the course, students will acquire skills in the practical execution of quantitative analyses reported in pharmacopoeial monographs and in the interpretation of experimental data.

On successful completion of this course students will be able to:

1. Describe the instrumentation and glassware required to perform the considered analytical methods.
2. Articulate knowledge and understanding of main volumetric e spectrophotometric analytical methods.
3. Provide a critical evaluation of methods available for quantifying a range of substances of pharmaceutical interest with reference to monographs of the Italian and European Pharmacopoeias.

Moreover, on successful completion of the lab practice, students will be able to:

1. Weigh a sample with an electronic analytical balance.
2. Prepare a solution with a known titre of a reagent (primary standard) by means of the proper calibrated glassware.
3. Transfer a given volume of a liquid or solution by means of calibrated glass pipettes or automatic pipettes.
4. Perform a titration with the appropriate indicator or a potentiometric apparatus for the determination of the end-point.
5. Determine, through a volumetric analysis, titre, mass or per cent purity of a given sample.
6. Calibrate the pHmeter and to use it for the pH measure of solutions.
7. Prepare the sample and to measure absorbance by means of a UV-Vis spectrophotometer.
8. Perform spectrophotometric quantitative determinations (even through construction of the calibration line).
9. Give a correct interpretation of obtained experimental data and to write out a report on the lab experiment.

Activities of the course are constituted by class lectures and case study along with laboratory experiences (single or group work). Attendance (at least 70%) at classes and laboratory experiences is mandatory. Attendance is attested by student’s own signature.

At the beginning of the course, laboratory shifts and the corresponding lab practice schedule are defined on the basis of the total student number.

During class lectures, all the subjects are presented in details. Students are asked to actively discuss about them and about a number of case studies.

During lab practice, students have to critically analyse experimental protocols and perform a number of quantitative analyses on samples of pharmaceutical interest. In lab, students are stimulated to discuss each other and with teachers about practical experiences and subjects seen during class.

At the end of every lab practice students have to write up and submit a report on the experience. The report is evaluated for the clarity of expression, correctness in the conduction of the analysis and the accuracy and precision of the final result. The report is given back to the student and commented on during the next lab session.

A trial is scheduled at the end of the lab practice.

The final exam is oral.

To take the exam, students need to book on line at Portale studenti of Università di Catania webpage (www.unict.it). Booking list is opened about fifteen days before the exam date.

Generalities on chemical quantitative analysis

Materials, reagents and laboratory apparatuses. Laboratory safety. Validation of an analytical method. Accuracy and precision. Outlier tests: 4d test and Dixon’s test. Analytical balances, weighing operations and methods.

Volumetric analysis

Preparation of solution with known concentration; determination of the concentration of solutions. Volumetric glassware and calibration. Calculations in volumetric analysis.

Acid-base titrations

Acidimetric and alkalimetric titrations. Preparation and standardization of acid or basic solutions. Acid-base indicators. Neutralization titrations in non-aqueous solvents: generalities, intrinsic acidity and alkalinity, differentiating and leveling effects, solvent classifications. Equilibria in non-aqueous solvents, criteria for choosing a solvent.

Applications with reference to monographs in Italian Pharmacopoeia XII ed. and European Pharmacopoeia IX ed. Determination of: Sodium Carbonate, Sodium Hydrogencarbonate, alkaline carbonates and hydroxides mixtures, alkaline carbonates and hydrogencarbonates mixtures, Ephedrine emihydrate, Nitrogen by Kjeldahl method, Ammonium salts, Tartaric acid, Phosphoric acid, Citric acid, Naproxen, Ibuprofen, Nimesulide, Omeprazole, Acetylsalicylic Acid, Benzyl Benzoate, Boric Acid, Saccharin, Nicotinamide, Diazepam, Aspartame, Atropine Sulphate, Sodium Benzoate, Morphine Hydrochloride, Sulfafurazole.

Precipitation titrations

Argentometric titrations. Preparation and standardization of a silver nitrate solution and of a ammonium thiocyanate solution. Titration methods (Mohr, Volhard, Fajans). Applications with reference to monographs in Italian Pharmacopoeia XII ed. and European Pharmacopoeia IX ed. Determination of: Alkaline Halides, Chlorobutanol emihydrate.

Complexometric titrations

Titrations methods. Preparation and standardization of an EDTA solution. Complexometric indicators. Applications with reference to monographs in Italian Pharmacopoeia XII ed. and European Pharmacopoeia IX ed. Determination of: Al, Bi, Ca, Mg, Pb, Zn, Hg, Fe salts. Determination of hardness in drinking water.

Oxidation-reduction titrations

Permanganometry, cerimetry, iodimetry, iodometry, bromometry.

Applications with reference to monographs in Italian Pharmacopoeia XII ed. and European Pharmacopoeia IX ed. Determination of: Calcium salts, Ferrous salts, Hydrogen peroxide solution (3%) and expression of its concentration in volumes of oxygen; Ferrous sulphate Heptahydrate, Menadione, Paracetamol, Nifedipine; Sodium Sulphite Heptahydrate, Ascorbic Acid, Ascorbyl Palmitate, Captopril; Potassium Permanganate, Tosylchloramide Sodium, Hydrogen Peroxide, Ferric Chloride Hexahydrate; Isoniazid, Phenol.

Electroanalytical methods

Potentiometric determination pH. Potentiometric detection of the end-point in titrations. Biamperometric determination of primary aromatic nitrogen: applications to sulfamidics (Sulfadiazine) and Benzocaine described in Italian Pharmacopoeia XII ed. and European Pharmacopoeia IX ed.

Spectroanalytical methods

UV-visible spectrophotometry

General discussion. Lambert-Beer law. Quantitative analysis: choice of the wavelength (l), general procedures for the quantitative determination. Linear regression analysis. Applications with reference to monographs in Italian Pharmacopoeia XII ed. and European Pharmacopoeia IX ed. Determination of: Chloramphenicol, Prednisolone acetate.

Fluorimetry

Principles and basic features of the technique, instrumentation, applications to the quantitative analysis of pharmaceutical substances.

The course includes lab practice. Lab practice schedule, for each academic year, is defined at the beginning of the course. A list of some typical laboratory experiences is the following:

1. Consignment of the work station. Safety in laboratory. Glassware and analytical balance usage.
2. Titre determination of a NaOH solution. Utilization of acid-base indicators.
3. Standardization of a HCl solution by means of anhydrous Na₂CO₃ as primary standard.
4. Quantitative determination of an unknown Na₂CO₃ sample through an acidimetric titration.
5. Standardization of a NaOH solution by means of a suitable primary standard.
6. Quantitative determination of an unknown L-(+) tartaric acid sample through an alkalimetric titration.
7. Quantitative determination of an unknown ascorbic acid (vitamin C) sample through an iodimetric titration.
8. Determination of total hardness in drinking water. Determination of mg/L of Ca⁺⁺ ion and Mg⁺⁺ ion.
9. Determination of per cent purity of a caffeine sample by UV spectrometry. Beer-Lambert law use.
10. pHmeter calibration and use. Potentiometric detection of the end-point in a neutralization titration. Construction of the titration curve.
11. Quantitative determination of an unknown caffeine sample by UV spectrometry. Construction of the calibration line.

Items 1 and 2 are textbooks, 3 -6 are reference books, Italian and European Pharmacopoeias (item 7) are the sources for ufficial quantitative analyses of pharmaceuticals

1. E. Abignente, D. Melisi, M. G. Rimoli – Principi di analisi quantitativa DEI medicinali - Ed. Loghìa, Napoli
2. G. C. Porretta - Analisi di preparazioni farmaceutiche.. Analisi quantitativa. - Ed. CISU, Roma
3. D. C. Harris - Chimica Analitica Quantitativa - Zanichelli, Bologna
4. A. Carreri - Manuale di Analisi Quantitativa dei Medicinali - EdiSES
5. R. Cozzi, P. Protti, T. Ruaro - Analisi chimica: moderni metodi strumentali - Zanichelli, Bologna
6. Vogel's Texbook of Quantitative Chemical Analysis - Fifth edition - Ed. Longman Scientific & Tecnical
7. Farmacopea Ufficiale Italiana XII edizione. European Pharmacopoeia IX edizione e supplementi