A Consumer Study on the Sensory Experience of new Herbal Topical Pain Relief Product in India

Introduction

Corresponding Author: Asif Ali and capsaicin, have gained attention for the management of chronic pain conditions with a good safety profile. 1 Their counterirritants properties further provide pain relief by desensitizing individuals to painful stimuli. 5,6uch counterirritants create hot or cold sensation which masks intense pain by interrupting the transmission of pain signals to the brain. 1 Patient acceptance of topical pain relief formulations depends on a variety of factors, including sensory characteristics (cooling, warming, etc), ease of application, after-feel, staining during and after use, greasiness, and intensity of odor.Consumer sensory studies help elucidate the acceptability of topical products, and thus, can guide the development of products that match the needs of the consumer, potentially improving treatment adherence and outcomes.Therefore, we conducted a consumer sensory study to compare a novel prototype of a gel formulation for musculoskeletal pain (marketed as Iodex Power Gel, referred to as Market Sample 1 in this study) with another commercially available topical pain relief formulation available in the Indian market (referred to as Market sample 2).

Study design
This was a prospective, quantitative, blinded, monadicdesigned, consumer sensory home-use test (HUT), conducted in three cities in India (Delhi, Mumbai, and Chennai).The study was conducted to evaluate the consumer acceptability of the sensory parameters of a novel prototype topical pain relief gel containing boswellic acid, methyl salicylate, menthol, and capsaicin in adults who were regular body pain sufferers.

Participants
A total of 320 participants were included in the study, comprising of adults who had musculoskeletal pain or joint pain within the past six months leading up to the study, with the last pain occurring within the preceding four weeks.Inclusion criteria were (i) use of pain relief balms, creams, gels, sprays, or a combination of these for previous pain occasions (ii) non-rejectors of the study (iii) users of gel formulations (iv) purchase decision maker (v) socioeconomic classification (SEC) A or B. 7 Exclusion criteria were (i) pregnant or nursing women (ii) participants with open wounds/lesions (iii) participants with a medical condition that required hospitalization or medical supervision (iv) participants with a history of allergies to topical pain relief products (sprays, gels, and creams) (v) rejectors of cooling and warming sensation of topical products (vi) rejectors of herbal ingredients including clove, camphor, capsaicin, Boswellia serrata (vii) participants of market research projects for pain relief in the preceding three months (viii) healthcare professionals dealing with pain relief and pain management.All participants signed a written informed consent document indicating their willingness to participate in the study.

Products tested
Iodex is a brand marketed by Haleon (earnstwhile GlaxoSmithKline Consumer Healthcare, Indian subcontinent).Iodex Power Gel was compared with a topical balm product, which is available in the Indian market.The formulations were referred to as Market Sample 1 and Market Sample 2, respectively.Market Sample 1 contains boswellic acid (65%) 3.85%, methyl salicylate 15%, pudina satva (menthol) 3%, kutuveera (capsicum extract) 0.02%.Products were tested blind (unbranded) but respondents were provided information on the ingredients in the samples to ensure they were not allergic to any of those ingredients.

Protocol for product testing and survey
Participants received a survey kit containing a consent form (signed before taking the survey), instructions for the use of the product, instructions on disposal of the product after use, one market sample each, blinded and assigned with 3 digitalphanumeric codes.The participants were divided into two cells or groups.One group (n=159) was given Market Sample 1 and the other group (n=161) was given Market Sample 2, to evaluate.The participant was to use the assigned market sample at least 3 times in a 7-day study period.The participants were instructed to apply the product on body parts where they typically apply similar topical pain relief products (e.g., knee joints, lower back, leg, etc).After using the product, the participants completed a webbased questionnaire (approximately 15 minutes duration to complete the survey) on the sensorial aspects of the product.The primary outcome was product performance for sensory variables.The questionnaire collected data on pre-application characteristics, during application characteristics, and postapplication characteristics.Broadly, the "pre-application" variables included color, smell or aroma of the product.The "during application" characteristics included texture, pleasant smell, ease of application, lack of messiness, fast absorption from the skin, and quick drying property.The "postapplication" variables included soothing, cooling, and warming sensation within 10 seconds of application, rapid cooling sensation, long-lasting warm/cool sensation, dual cooling and warming action, relevance to the pain experienced, suitability for regular use, non-greasy/nonsticky after feel, lack of residue, lack of staining of clothes, and pleasant smell after application.The agreement rating scale included the responses "Yes, I agree", "No, I don't agree", and "I don't know".The outcome of the study was the agreement of participants with the variables evaluated.

Data analysis
Data was collected by ConfirmIt, and exported to a Microsoft Excel database (Microsoft Corporation, Redmond, Washington, USA).Frequency and percentage was calculated for categorical variables, and results were presented as percentage.A two-tailed test was used for statistical analysis.Corresponding Author: Asif Ali

Study participants
A total of 320 participants were included in this study.Demographic data of the study population are presented in Table 1

During application variables
Market Sample 1 received high consumer agreement scores for the variables evaluated during application.All participants agreed with the claims related to texture, ease of application, and the lack of messiness in application, while 99% of participants opined that the formulation is quickly absorbed from the skin, and dries quickly.Market Sample 1 (Iodex Power Gel) performed significantly better for lack of messiness in application, rapid absorption from the skin/surface, and quick-drying property, compared with Market Sample 2 (Topical Balm).

Post-application variables
Market Sample 1 received high consumer agreement scores (>90%) for most variables evaluated after application (except fast soothing sensation within 10 seconds and fast warming sensation within 10 seconds), as described in Table 4.However, 94% of respondents agreed that the product provided a long-lasting warming sensation.Market Sample 1 performed significantly better for long-lasting cooling sensation and rapid cooling sensation within 10 seconds, compared with Market Sample 2 Corresponding Author: Asif Ali # Statistically significant at 90% level of confidence; two-tailed test.

Summary of the key benefits of Market Sample 1 (Iodex Power Gel)
At least 90% of consumers agreed that Market Sample 1 provides fast cooling at the usual site of pain in 10 seconds, provides long-lasting cooling, and provides dual cooling and warming sensation (Figure 1).At least 90% of consumers agreed that the product is convenient and easy to use, gets absorbed quickly, dries quickly, has a pleasant smell, has no greasy after-feel, leaves no sticky after-feel, and leaves no residue.Figure 2 summrizes the sensory paramters for which Iodex Power Gel scored significantly higher than Topical Balm.

DISCUSSION
The gel formulation scored higher over the balm formulation for long-lasting cooling sensation, rapid absorption from the skin, and rapid drying.These attributes of the formulation with a combination of ingredients with proven effectiveness in acute and chronic musculoskeletal conditions making it suitable for topical pain management.Counterirritants have received considerable support for the topical management of musculoskeletal pain.They act by inducing cutaneous irritation or pain so as to suppress subdermal pain (i.e., musculoskeletal pain).Counterirritants exert their effect through cooling or heating stimuli, or both. 8This consumer sensory study demonstrated that Market Sample 1, which is a combination of boswellic acid, menthol, methyl salicylate and capsicum extract, provides a rapid cooling sensation as well as a long-lasting cooling and a dual warming-cooling sensation.Furthermore, it leaves no residue, has an acceptable after-feel, dries easily, and is rapidly absorbed from the skin.These properties of counterirritant potential and high acceptability of the product among consumers indicate the potential for routine use of this product.Menthol has been used for pain relief since ancient times.It activates Transient Receptor Potential Melastatin 8 (TRPM8), leading to increased nitric oxide production and subsequent vasodilation.This increased cutaneous blood flow is in contrast to traditional ice cooling, which reduces cutaneous blood flow.In addition, menthol is a weak sodium channel blocker, leading to a weak, localized anesthetic effect through reduced nociception.This desensitization of nociception occurs at low concentrations of menthol, while high concentrations cause irritation. 9,10Clinical studies have demonstrated that menthol gels provide a cooling effect on the skin for at least 40 minutes. 11Another study demonstrated that topical menthol was more effective than ice application in relieving soreness at rest and during muscle contraction. 12ombined with the favorable sensory variables noted in this study, menthol is a useful topical agent for the management of musculoskeletal pain.Methyl salicylate exerts anti-inflammatory and analgesic effects through vasodilation and an increase of tissue temperature.It has the advantage of low systemic absorption.It interrupts the transmission of pain signals by modifying a cation channel in sensory neurons. 13It activates nociceptors but does not stimulate warm fibers, and therefore, the burning sensation lacks a thermal component.Topical preparations often combine methyl salicylate with menthol, so as to provide a warming sensation (through methyl salicylate) and a cooling sensation (through menthol). 8Methyl salicylate has the advantage of being a penetration enhancer, thus allowing better delivery of other herbal ingredients into the skin. 14tudies on the topical application of methyl salicylate plus menthol in patients with muscle strain demonstrated 40% greater pain relief with the combination as compared to placebo. 13Capsaicin activates a non-selective calcium-permeable ion channel (transient receptor potential vanilloid 1; TRPV1) present at the terminals of nociceptors. 15,16xtracts of the Boswellia serrata plant have analgesic and anti-inflammatory action.3-O-acetyl-11-keto-β-boswellic acid (AKBA) and 5-Loxin decrease pro-inflammatory mediators and enzymatic degradation of cartilage.This regulation of inflammatory responses improves physical functioning and decreases pain in patients with osteoarthritis. 17Currently, several topical vehicles are available for drug delivery in the market.Gels provide stiffness to a solution or a colloidal dispersion and have the advantage of being nongreasy, and drying as a non-greasy film.In addition, gels can be applied on hairy areas and are cosmetically elegant. 18This study evaluated a gel formulation (market sample 1) and reported that over 90% of consumers accepted that it dries quickly, lacks a greasy after-feel, and does not leave a residue.This increases the acceptability of the formulation, as reflected by the fact that 94% of participants in this study agreed that the formulation was suitable for regular use and was relevant for the pain experienced.The effectiveness of Iodex Power Gel formulation can be attributed to the science of each active ingredients discussed above, coupled with superior consumer sensorial experience.The combination of active ingredients in this formulation (i.e., Boswellia serrata, methyl salicylate, menthol, and capsaicin) results in a synergistic action against acute and chronic inflammatory conditions such as pain of musculoskeletal origin, muscle spasms/sprains, exertion soreness, lower back pain, and arthritic conditions.Formulation attributes (e.g., deep penetration [with permeation enhancement], long lasting relief, and faster action) along with ideal consumer sensorial experience accounts for the quick and superior alleviation of pain and impact on quality of life perspective (improved mobility and reduced stiffness/soreness).Furthermore, formulation features like fast drying, residue-free delivery of actives to the site of action, and superior application experience with no irritation of the skin encourage frequent use, thereby improving patient compliance and self-management of pain episodes.

CONCLUSION
Patient acceptability of topical pain relief formulations is a key driver of compliance and product effectiveness.The findings of the consumer sensory study demonstrate that a novel herbal gel formulation for pain relief has ideal properties of non-greasiness, lack of residue, quick-drying, ease of application, pleasant odor, rapid cooling sensation, dual cooling-warming sensation, and was suitable for regular use.This suggests that the investigated market sample 1 (Iodex Power Gel) could be a useful adjunct to the pharmacological management of musculoskeletal pain, without adding to the burden of adverse effects.

Figure 1 .
Figure 1.Key findings of sensory variables analyzed in the study

Table 1 . Demographic details of the study population
.