11961 - Special Methodologies in Pharmaceutical Analysis (GR.A)

Learning outcomes

The aim of the course is to provide the knowledge about analytical methods (e.g. UV spectrophotometry, chromatography and titrimetry) in qualitative and quantitative determination of pharmaceutical compounds. The course includes laboratory activity.

Course contents

Theory

Non-aqueous titrations. Classification of the solvents used in non-aqueous titrations. Autoprotolysis constant and dielectric constant of solvents used in non-aqueous titrimetry. Apparent pH (pH*). Solvolysis reaction of weak electrolytes. Pharmacopoeial applications of non-aqueous titrations.

Potentiometry. Theory: Nernst equation; reference electrodes and working electrodes. The glass electrode for pH measurement (pH-meter); ion-sensitive electrodes in pharmaceutical analysis. Potentiometric titrations.

Biamperometry. Polarized electrodes. Diazotisation titration and Karl-Fisher titration.

Conductimetry. Theory: electrical conductivity of electrolytic solutions. Conductance cell. Specific conductivity and equivalent conductivity. Conductimetric titration techniques.

Ultraviolet and visible spectrophotometry. Keypoints. Factors governing absorption of radiation in the UV/vis region. Beer-Lambert law. Instrumentation. UV spectra of some representative drugs. Deconvolution of spectra from binary mixtures of drugs. Derivative spectrophotometry. Difference spectrophotometry. Spectrophotometric derivatization reactions: Ellman reagent; Bratton-Marshall method in analysis of sulphamidics. Applications in pharmaceutical analysis.

Chromatography. Fundamentals. Theory of chromatographic separations, thermodynamic relationship: retention time, efficiency, selectivity, capacity factor, resolution. Principal classification of chromatographic techniques: gas chromatography and liquid chromatography. Adsorption and partition, chromatography. High performance liquid chromatography (HPLC), instrumentation, detectors for drug identification and quantification. Characteristics and criteria of choice. Quali-quantitative analysis by chromatographic techniques. Introduction of gas chromatography (GC).

 

Laboratory activity

- Non-aqueous titrimetry. Determination of weak acids (sulphamidics) and weak bases (sodium acetate, lidocaine hydrochloride, alanine).

- Potentiometric titration of phosphoric acid.

- Conductimetric titration of sodium acetate.

- Diazotisation titration of sulphamidics (pharmacopoeial assay by biamperometric end-point detection).

- UV/vis spectrophotometry. Calibration of absorbance scale by using a cyanocobalamine solution (calibration graph).

- Spectrophotometric UV-vis analysis of Fe(II) in tablets by complexation with o-phenantroline.

- Spectrophotometric UV-vis analysis of procaine by derivatization with Bratton-Marshall reagent.

- Derivative UV spectrophotometric analysis of salicylic acid as related substance in aspirin.

- HPLC analysis of salicylic acid as related substance in aspirin.

- Final laboratory examination

Readings/Bibliography

1) V. CAVRINI, V. ANDRISANO, Principi di Analisi Farmaceutica, third edition, Esculapio, 2013.

3) Slides from lessons.

Teaching methods

The theoretical lessons and lab activity are intended to provide the knowledge ofchemical instrumental techniques used in pharmaceutical analysis.

Assessment methods

During the laboratory activity the learning is assessed by the discussion of the achieved experimentals skills. A final lab examination consists in the application of analytical methodologies to verify the skills of the students.

The final test will be an oral presentation about subjects dealt during the course.

Teaching tools

Theoretical lessons will be held by using slides.

In the laboratory activity the students will use analytical instrumentation such as: conductometers, potentiometers, spectrophotometer, pH-meter, liquid and gas chromatographs (GC and HPLC), suitable for the drug quality control.

Office hours

See the website of Vincenza Andrisano