Stability of extemporaneously prepared sitagliptin phosphate solution

Area of Science:

• Pharmaceutical Sciences
• Drug Formulation
• Diabetes Mellitus Management

Background:

• Sitagliptin phosphate (SiP) is a DPP-4 inhibitor used for type 2 Diabetes Mellitus.
• Oral solid dosage forms present challenges for patients with swallowing difficulties or feeding tubes.
• Extemporaneous preparation of liquid formulations can improve medication accessibility.

Purpose of the Study:

• To extemporaneously prepare a stable 1% w/v sitagliptin phosphate (SiP) solution.
• To assess the stability of the prepared SiP solution under various storage conditions.
• To provide an alternative dosage form for patients unable to take oral solids.

Main Methods:

• Four SiP solutions were prepared using pure SiP powder.
• The most suitable formulation (T4) was selected based on organoleptic properties.
• Stability studies involved storage at room temperature and accelerated conditions for 4 weeks.
• Evaluated parameters included assay, pH, organoleptic properties, related substances, and microbial contamination.
• High-Performance Liquid Chromatography (HPLC) was used for SiP quantification.

Main Results:

• The selected SiP solution maintained an average pH between 3 and 4 throughout the study.
• SiP concentration remained close to 100% after 4 weeks of storage under both conditions.
• No significant degradation or microbial contamination was observed.
• The prepared solution exhibited acceptable organoleptic properties.

Conclusions:

• A stable extemporaneously prepared sitagliptin phosphate solution was successfully developed.
• This liquid formulation can benefit type 2 diabetes patients with swallowing impairments or those using feeding tubes.
• Community pharmacists can utilize this method to prepare sitagliptin solutions from pure powder.