An active ingredient from the group of an antihistamine, a decongestant,
an antitussive or anticholinergic is dissolved in a suitable solvent and
added to a dispersion of tannic acid in water to form the tannate salt
complex of the active ingredient. The active ingredient tannate salt
complex without isolation or purification is then added to a liquid or
semi-solid medium composed of thickening, suspending, coloring,
sweetening and flavoring agents, with stirring. Thereafter,
preservatives, pH-adjusting and anti-caking agents in a suitable solvent
are mixed with the liquid or semi-solid medium to generate a therapeutic
dosage form.