Stability of zoledronate gel emulsion in virgin coconut oil

Objective: This study aimed to analyze the physical stability and drug content of zoledronate (ZOL) gel emulsion in virgin coconut oil (VCO) as a new pharmaceutical product at 25°C as room temperature and 40°C as an accelerated temperature for a stability physics test. Methods: The ZOL gel emulsion comprises the following ingredients: 0.16% ZOL powder, 2% carboxymethyl cellulose, 5% VCO, 0.44% sodium benzoate, and 0.009% antioxidant butylated hydroxytoluene, and distilled water. Samples of this gel emulsion were stored for 1 month at 25°C and 40°C, and the parameters used for stability tests were pH, viscosity, spreadability, and adhesive strength. The drug content was also evaluated with a spectrophotometer. The ZOL gel emulsion was evaluated against these metrics on days 1, 7, 14, and 28. Results: The results showed that ZOL pH, viscosity, spreadability, adhesive strength, and drug content gel emulsion were clinically stable over 28 days of storage at 25°C, whereas it was not stable when stored at 40°C for the same duration. pH value of ZOL gel emulsion significantly decreased at 28 days (p<0.05). Also for viscosity, adhesive strength, and drug content of ZOL gel emulsion showed statistically significant (p<0.05), except for spreadability value (p>0.05). The spreadability value between ZOL gel emulsion that stored at 25°C and at 40°C showed no significant result at 7 and 14 days (p>0.05). Conclusion: ZOL gel emulsion was stable at 25°C when stored for 28 days, suggesting that this is a suitable storage temperature at which its physical stability and drug content can be maintained.