Zn(II)-theophylline-ethylenediamine: structure and pH stability

Area of Science:

• Pharmaceutical Chemistry
• Materials Science

Background:

• Theophylline is a widely used bronchodilator for respiratory diseases.
• Its bitter taste and poor solubility present formulation challenges.

Purpose of the Study:

• To synthesize and characterize a zinc-aminophylline complex.
• To evaluate its physicochemical properties and potential for improved drug delivery.

Main Methods:

• Synthesis of Zn(II)-aminophylline complex.
• X-ray diffraction for structural determination.
• Solubility studies at 30°C.
• pH-dependent hydrolysis and drug release experiments.

Main Results:

• A tetrahedral Zn(II)-aminophylline structure was confirmed.
• The complex exhibited 180-fold lower water solubility than theophylline.
• Stable in alkaline conditions, it hydrolyzed in acidic environments, releasing theophylline in a pH-dependent manner.

Conclusions:

• The zinc-aminophylline complex offers reduced solubility and controlled release properties.
• This can be leveraged to formulate palatable and effective theophylline dosage forms.
• Potential for improved patient compliance in treating respiratory conditions.