title: On the adequacy of the draw-sealing of gas-filled glass ampoules.
abstract: It is recommended that a very clear distinction be made between draw-sealed and tip-sealed glass ampoules. We would, that is, defend the draw-seal for its proven value and its demonstrated freedom from microscopic channels. Where tip-sealing is still employed, we would suggest its reevaluation. Little more can be said in the absence of an immediate reason for the differences in the behavior of the glass in the course of the two procedures. Others may be able to explain the persistence of the capillary in the tip-seal in physico-chemical terms. As to balloon-seals, the third "variety" in common use, it would seem that their characteristics must derive from the way they are made. Ballooned tip-seals appear to have been shown by Greiff et al. (1975) to suffer the same shortcomings as the simple tip-seal. Where a draw-sealed ampoule is heated at the tip after the completion of the seal, a ballooned end would seem to have to retain the true seal effected in the draw process. It is perhaps sufficient to let the subject rest with a reassurance as to the adequacy of the common draw-seal.
mesh_terms: D001128:Argon; D004349:Drug Packaging / Q000379:methods*; D005069:Evaluation Studies as Topic; D005612:Freeze Drying; D005898:Glass; D013058:Mass Spectrometry
chemical_list: D001128:Argon