Glass tube for pharmaceutical containers and process for the production of a glass tube

A glass tube for pharmaceutical containers, comprising:

• an inner surface with an inner diameter (di) and an outer surface with an outer diameter (do);
• a length (la) defined along a longitudinal axis between a first end and a second end, the length (la) being at least 125 mm, the first end is a first closed end and the second end is a second closed end;
• a middle section spanning a distance of five times the inner diameter (di), the middle section being centred around the position of one half of the length (la);
• a first location at a distance of 15 mm from the first end;
• a second location at a distance of 15 mm from the second end;
• a first intermediate location offset from the first end by a distance that is between ten times the inner diameter (di) and at most 75 mm;
• a second intermediate location offset from the second end by a distance that is between ten times the inner diameter (di) and at most 75 mm;
• a first vicinity between the first location and the first intermediate location, the first vicinity being devoid of a first lamp ring;
• a pressure compensation vent hole passing from the inner surface to the outer surface at the first vicinity and/or the second vicinity;
• a ratio of transmittance for at least one wavelength in a range of 350 to 800 nm for the first vicinity and the middle section is at least 0.97,
• wherein the first vicinity has a first hydrolytic resistance characterized by a first alkali leachability and the middle section has a middle hydrolytic resistance characterized by a middle alkali leachability, wherein the first and middle alkali leachabilities are determined as relative concentration in an eluate prepared according to ISO 4802-2:2010, except that initial rinsing steps with distilled water at ambient temperature are omitted,
• wherein the first alkali leachability is less than 0.9 μg cm−2, and
• wherein a ratio of the first and middle alkali leachabilities is between 0.5 and 2.0.