Pharmaceutical agent for the treatment of diabetes mellitus

A pharmaceutical composition stable on storing and being suitable for the treatment of diabetes mellitus consisting of a physiologically acceptable excipient and an active compound combination, which contains, as the active compound combination,

• (a) an insulin derivative of the formula I ##STR5## in which R.sup.1 denotes H or H--Phe
• R.sup.30 represents the radical of Ala, Thr or Ser and
• R.sup.31 represents a physiologically acceptable organic group of basic character of the formula X.sub.n --S which has up to 50 carbon atoms, in which
• n is 0, 1, 2 or 3,
• X represents identical or different radicals of naturally occurring neutral or basic .alpha.-amino acids and
• S denotes OH or a physiologically acceptable group which blocks the carboxyl group but S being, if n is 0, a positively charged or protonatable basic radical or, if n is greater than 0, S can carry such a radical, or in which, if n is 2 or 3, the C-terminus X--S can also represent the homoserine-lapton radical
• and which contains or does not contain a terminal carboxyl function or an ester or an amide thereof,
• with an iso electric point between 5.8 and 8.5, and
• (b) an insulin of the formula I in which R.sup.1 denotes H or H--Phe, R.sup.30 represents Ala, Thr or Ser and R.sup.31 denotes OH, or
• (b2) physiologically acceptable salts thereof, or
• (b3) proinsulin or
• (b4) C peptide or
• (b5) a combination thereof, component (a) being present in an amount of at least 1% by weight.