Stability of codeine phosphate in an extemporaneously compounded syrup

Area of Science:

• Pharmaceutical Sciences
• Compounding Pharmacy
• Analytical Chemistry

Background:

• Codeine phosphate is a commonly prescribed opioid analgesic.
• Ensuring the stability of extemporaneously compounded medications is crucial for patient safety and therapeutic efficacy.
• Limited data exists on the long-term stability of codeine phosphate in specific compounded syrup formulations.

Purpose of the Study:

• To evaluate the stability of codeine phosphate in an extemporaneously compounded syrup.
• To determine the degradation profile of codeine phosphate over 98 days under specified storage conditions.
• To assess the suitability of Ora-Sweet syrup vehicle for compounding codeine phosphate formulations.

Main Methods:

• Codeine phosphate 3 mg/mL syrup was prepared using USP-grade ingredients and Ora-Sweet vehicle.
• Samples were stored in amber polyethylene terephthalate bottles and amber oral syringes.
• Stability was assessed over 98 days at room temperature (22-25°C) protected from light using a stability-indicating HPLC method.
• Degradation was defined as >7% loss of initial concentration.

Main Results:

• The compounded codeine phosphate syrup retained >93% of its initial concentration for 98 days.
• No significant changes in physical appearance (color, clarity, odor, solids) or microbial growth were observed.
• The pH remained stable at 4.2 throughout the study period.

Conclusions:

• Codeine phosphate 3 mg/mL in Ora-Sweet syrup is stable for at least 98 days when stored in amber bottles or oral syringes at room temperature, protected from light.
• The findings support the use of this formulation for short-term storage and administration.
• This study provides valuable stability data for pharmacists compounding codeine phosphate syrups.