ABSTRACT

The profession of Pharmacy is one saddled with the responsibility of providing appropriate medicines, drug information and pharmaceutical care for the patients. The Physician is left to no choice following diagnoses to seek for drugs that will be used for the treatment of the patient. Pharmacy has several sub-specialties, including Pharmacognosy, Pharmaceutical Chemistry, Pharmaceutics and Industrial Pharmacy, Pharmacology, Pharmaceutical Microbiology, Clinical Pharmacy and Pharmacy Administration. All these sub-specialties are designed towards optimising the benefits derivable from the administration of a given drug and in particular towards a holistic understanding of drugs. In addition, the Pharmacist is also trained in the rudiments of management, forensic science and accounting.

In order to ensure that medicines provided for the care of patients are of the right quality, the discipline of pharmaceutical analysis is saddled with the responsibilities of designing, developing and adopting various analytical methodologies that provide the bases for guaranteeing the quality and safety-in-use of these medicines. The two broad category of methods adopted are non-instrumental (classical) and instrumental (physicochemical methods). These methods run through the various specifications in the Pharmacopeias. However, in many instances, it becomes difficult to adopt some of the techniques due to the sophistication that is required which is beyond the reach of average Pharmaceutical Analyst in poor-resource economies like Nigeria. In order to circumvent this disadvantage, derivatization technologies are adopted which convert pharmaceutical molecules to new species that have enhanced spectral and migration properties in UV-VIS spectrophotometry and Chromatography respectively. Several derivatization reactions have been reported but I have focused my research career on the development of novel methods using the tripodal reactions of azo dye derivatization, Schiff base formation and charge transfer complexation. These have provided the trawls for my research career in the last 18 years. In all the three reaction types, colours are generated and these have provided highly sensitive determination of drug molecules in drug preparations. The coloured substances resulting from the derivatization technologies have been investigated as indicators of solvent polarity, potential non-toxic food colourants and also as sensitive and selective chemosensors for environmentally important heavy metals and inorganic anions such as cyanide and nitrites.

The application of the tripodal reactions is also being extended to the development of analytical techniques for the impurities profiling of drug preparations such as griseofulvin, paracetamol and cephalosporins. In recent times, development of novel Schiff bases as chemosensors for anions and excellent solvent probes has provided patentable compounds.

This inaugural lecture discusses the various end-products of these reactions and in particular emphasises the need to be careful with consumption of coloured and flavoured substances due to their cumulative effects on the body and based on the fact that acceptable daily admissible dose is still subject to variation across the various regions of the world.