Intranasal Nalbuphine Formulation for Faster Management of Pain in Prehospital Scenario; Its Safety and Comparative Efficacy in Animal Models

Aim: Nalbuphine (NLB) is an approved opioid analgesic for the management of severe pain in wounds, battlefield injuries and is recommended to subsidize labour pain during childbirth. The study aims to develop an intranasal opioid formulation for faster pain relief. Secondly to avoid patient inconvenience and make it available for buddy care. In case of war, accident or any natural calamities the feasibility of giving drugs from the parenteral route is not feasible as it requires high skilled medic/paramedic staff. Materials and Methods: Different formulations were made using NLB as an Active Pharmaceutical Ingredient (API), prepared formulations (F1-F10) were characterized and evaluated for various parameters. The formulation F5 was optimized as it met the desired criteria. F5 was further studied for its efficacy in an established pain model using Eddy’s hot plate method and pain scoring in animals. Pharmacodynamics study was conducted in Sprague dawley rats which were further verified by gamma scintigraphy using 99mTc-pertechnetate labelled NLB showing significant and rapid deposition in the brain tissue. Results: NLB nasal formulation was optimized successfully; at pH 6.4±0.10 and viscosity 2.5±0.13 (cps). Osmolarity and percent drug release of optimized nasal drop at 240 min was found to be 288±18 milliosmol/litre and 96.98±3.1% respectively. Gamma scintigraphy study results revealed that the formulation (F5) was able to deliver NLB to the brain within 10 mins of administration and remained localized up to 240 min. Pre-clinical subacute toxicity profiling of optimized formulation was done in Sprague dawley rats at 3X dose. Conclusion: Data obtained from the study indicate that the developed NLB nasal formulation has better efficacy for pain management than conventional I.M injection.