Understanding the Concept:
Syrups are concentrated aqueous solutions of a sugar, typically sucrose. The specific concentration required for a solution to be self-preserving varies between different compendial standards.
Compendial Comparison Framework:
• Indian Pharmacopoeia (IP) British Pharmacopoeia (BP): Define Syrup (Simple Syrup) as a concentrated solution containing 66.7% w/w sucrose. This mass-to-mass ratio creates a high osmotic pressure that prevents microbial growth, rendering the solution self-preserving.
• United States Pharmacopeia (USP): Defines simple syrup at a concentration of 85% w/v, which corresponds to approximately $64.74\%\text{ w/w}$.
Since the prompt specifies Indian Pharmacopeial compliance, the concentration must be expressed as $66.7\%\text{ w/w}$.