Novel Herbal Emulgel for Topical Pain Relief Based on Capparis spinosa and Capsicum annuum. [Patent No. 3008]

Background Traditional medicine (TM) has long played a vital role in global healthcare systems. The World Health Organization reports that a significant proportion of the world’s population relies on traditional and complementary medicine for primary healthcare, particularly in managing chronic conditions. Among widely used folk remedies, Capparis spinosa L. (caper root) and Capsicum annuum L. (cayenne) are traditionally applied topically for musculoskeletal pain relief, including back pain and intervertebral disc herniation. However, their direct application is often associated with adverse skin reactions such as irritation, hypersensitivity, and burns. This limitation necessitates the development of safer, standardized pharmaceutical formulations. Objective This study aimed to develop an innovative topical emulsifying gel (emulgel) formulation incorporating extracts of Syrian caper and cayenne, enhancing therapeutic efficacy while minimizing adverse effects. The work further aimed to validate its analgesic activity experimentally and translate traditional knowledge into a modern pharmaceutical product, ultimately leading to a granted patent for the formulation. Methods A two-stage preparation process was employed: 1. Extraction of active compounds: Aqueous extracts of Capparis spinosa L. (roots, leaves, and fruits) were obtained via boiling and filtration following established protocols (e.g., Maresca et al., 2016). An oily extract of Capsicum annuum L. was prepared by maceration in olive oil for 48 hours. 2. Emulgel formulation: The gel base was prepared using carbopol, neutralized with triethanolamine (pH ≈ 6). The oil phase (paraffin oil and isopropyl myristate) and aqueous phase (propylene glycol, preservatives, Tween 80) were prepared separately and heated. Phases were combined to form an emulsion, which was then incorporated into the gel base to produce the emulgel. Active extracts were incorporated at an optimized ratio (aqueous:cayenne oil = 1:3; total active phase ≈ 45%). Pharmacological evaluation:An in vivo experimental study was conducted using mice (n=18), divided into three groups: Placebo control Reference drug: diclofenac emulgel 1% Test formulation: caper–cayenne emulgel Analgesic activity was assessed using the tail-flick latency test under infrared radiation, with measurements taken at baseline and at 10-minute intervals for 90 minutes. Maximum Possible Effect (MPE%) was calculated, and statistical analysis was performed using ANOVA and independent t-tests. Results The developed emulgel demonstrated significant topical analgesic activity: At early time points (10–40 minutes), the caper–cayenne emulgel showed superior analgesic effects compared to diclofenac (P < 0.05). At later time points (50–90 minutes), diclofenac exhibited greater efficacy (P < 0.05). Statistical analysis confirmed a significant interaction between treatment type and time, indicating differential pharmacodynamic profiles. These findings highlight the rapid onset of action of the herbal emulgel formulation. Discussion The study successfully bridges traditional medicine and modern pharmaceutical technology by transforming crude plant applications into a stable, controlled-release emulgel system. The formulation improves: Safety (reduced irritation compared to raw application) Bioavailability of active compounds Ease of application and patient compliance The early superior analgesic effect may be attributed to synergistic mechanisms: Capsaicin-induced desensitization of nociceptors Anti-inflammatory and antioxidant activity of caper phenolics The emulgel system enables incorporation of both hydrophilic and lipophilic components, ensuring optimal delivery. These advantages support its potential use in treating rheumatism, disc herniation, and sports injuries. Importantly, this research resulted in the development and successful registration of a patented pharmaceutical formulation, confirming its novelty, applicability, and industrial relevance.