Long-acting drug delivery systems have gained widespread popularity due to their numerous advantages over conventional methods of drug administration. These systems offer several benefits, including reduced dosing frequency, improved patient compliance, minimized side effects, and the ability to maintain therapeutic drug levels for extended durations. Reservoir-based systems, such as polymeric implants, osmotic pumps, and electromechanical systems, are commonly employed as long-acting drug delivery mechanisms. However, these devices are susceptible to the accumulation of osmotic pressure within the drug reservoir, which can compromise their integrity and affect the efficacy of drug release. Various techniques, such as the Van't Hoff equation, freezing point determination, or vapor pressure osmometry, are currently utilized to estimate the osmotic pressure generated by drug delivery systems.