No abstract

An apparatus is described which permits continuous monitoring of the UV absorbance of one phase in a vigorously agitated mixture of an aqueous and a water-immiscible organic solvent.Photometric titrations, using sodium hydroxide titrant, are performed in such a two-phase system on weak acid drug substances which show no spectral change upon deprotonation. Theoretical titration equations are derived and verified experimentally by titrating dextromethorphan hydrobromide.

Twenty-nine drug compounds are chromatographed in acidic, neutral, and alkaline solutions containing varying amounts of water and methanol on a column of Amberlite XAD-2 nonionic resin. Cationic conjugate acids of amine drugs are adsorbed via "salt-adsorption". Their retention volumes depend on concentration and type of anion (e.g. Cl , CI04 ) added to the mobile phase as well as on its pH and solvent composition. Pharmaceutical syrups can be analyzed without prior treatment when short pre-columns containing anion-exchange resin and XAD-2 are added. As examples, synthetic and commercial syrups are analyzed for phenylephrine hydrochloride, acetaminophen, glyceryl guaiacolate, and dextromethorphan hydrobromide.

No abstract

A r a p i d and s p e c i f i c r e v e r s e d -p h a s e i o n -p a i r i n g h i g h performa n c e l i q u i d chromatographic p r o c e d u r e f o r p u t r e s c i n e , s p e r m i d i n e and s p e r m i n e i s r e p o r t e d . The i o n -p a i r i n g r e a g e n t , h e p t a n e s u lf o n a t e , w a s employed and o-phthalaldehyde and 2-mercaptoethanol were used f o r o n -l i n e post-column d e r i v a t i z a t i o n and s u b s e q u e n t f l u o r e s c e n c e d e t e c t i o n . Experiments were c a r r i e d o u t t o d e t e r m i n e t h e e f f e c t s of s e v e r a l v a r i a b l e s s u c h as pH, c o n c e n t r a t i o n of t h e aqueous b u f f e r , c o u n t e r -i o n c o n c e n t r a t i o n , and t h e p e r c e n t a g e of o r g a n i c m o d i f i e r i n t h e moving phase. l i m i t s f o r t h e polyamines ranged from 120 pmoles f o r s p e r m i n e t o 1 2 pmoles f o r p u t r e s c i n e .