Abstract: Quaternary ammonium salts of furosemide are stable and highly water-soluble, affording thereby solid oral dosage forms which are more bioavailable, oral liquid dosage forms hitherto unavailable, and injectable dosage forms of furosemide with higher concentration, hence lower volume, which do not add to the sodium ion burden of patients to whom it may be administered.

Abstract: Theophylline concentrations in body fluids can be determined by a color reaction. The theophylline is converted to theophyllidine by reaction with an alkali such as sodium or potassium hydroxide at an elevated temperature and, after neutralization of the alkali with an organic acid, the theophyllidine formed is coupled with a chromogen to yield a color whose depth is proportional to the theophylline concentration in the body fluid being tested. The improved procedure utilizes a solid alkali for the heating step and a non-corrosive acid for the neutralization. An improved chromogen yields a bright, relatively stable purple color.