Rheological and Pharmacological Evaluation of High-Strength Zingiber officinale Topical Ointments for Antinociceptive and Anti-Inflammatory Effects

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Background: Zingiber officinale (ZO) is known for its pain-relieving and anti-inflammatory properties, but high-concentration topical formulations have not been well studied. This study evaluates how high extract loading affects rheological behavior and pharmacological activity.

Objectives: This study formulated ZO ointments with varying high concentrations and evaluated the impact of composition on rheological properties, antinociceptive, and anti-inflammatory efficacy in Wistar rats.

Materials and Methods: Dried ginger rhizomes were macerated in ethanol, and the extract was incorporated into ointment bases at 51.28% (formulation A), 41.03% (formulation B), and 30.77% (formulation C) w/w. Formulations were tested for physicochemical properties and efficacy using the hot-plate paw-lick and egg albumin-induced paw oedema assays. Rats received vehicle, methyl salicylate, or ZO extract (ZOE) ointments.

Results: Higher extract concentrations had better ointment spreadability and appearance. All formulations showed pseudoplastic flow, with viscosity inversely related to extract content. ZOE ointments produced dose-dependent antinociceptive and anti-inflammatory effects, with formulation A having the most significant effects.

Conclusion: Incorporating high concentrations of ZOE into topical ointments significantly enhanced both antinociceptive and anti-inflammatory efficacy. Formulation A provided the optimal balance of superior pharmacological activity and desirable physical properties. These findings indicate that ZOE ointments with higher concentrations have the potential to relieve localized pain and inflammation.