two different sustained-release theophylline preparations were used to determine ( 1 ) if the serum theophylline concentrations ( stc ) depend on the type and dosing schedule of the preparation , ( 2 ) the relationship between stc and the circadian variations in asthma , and ( 3 ) the effect of stc on sleep quality and respiratory patterns during the night .
C0004096
asthma
C0039771
stc