Formulation and Evaluation of Polyherbal Topical Anti-Inflammatory Emulgel

 

Pratiksha V. Shrikhande*

Department of Pharmaceutics, IBSS College of Pharmacy, Malkapur- 443101, Maharashtra, India

*Corresponding Author E-mail:  pratiksha_shrikhande@rediffmail.com

 

ABSTRACT:

The present study was conducted to develop an emulgel formulation containing potential herbal anti-inflammatory agent viz., tea tree oil, lemongrass oil, ginger oleoresin & capsaicin. Inflammation and rheumatism remain serious problem in the present era. Although there are number of allopathic formulation available in market for the treatment of inflammation, but these suffer from side effects like heartburn, stomach pain, nausea, vomiting, diarrhea, constipation, liver damage, fluid retention, nephrotoxiciy etc. It is considered that the herbal medication as safer as compared to that of allopathic medicine in the market. The herbal components like Tea tree oil, Capsaicin, Ginger oleo-resin, Lemon grass oil has been selected for the development of anti-inflammatory formulation, as from literature review it revealed  that these are effective in the treatment of inflammation. Carbopol 940 can be used as gelling agent. Tea tree oil, lemon grass oil, linseed oil & capsaicin were incorporated for topical delivery system in the gel form and cow ghee was used as a permeation enhancer. The gels were subjected for evaluation on the basis of appearance, pH, spreadability, extrudability, rheological behavior, in vitro release performance, anti-inflammatory study. Two different formulations of with and without permeation enhancer were screened at preliminary level and were compared with marketed preparation containing diclofenac sodium. The anti-inflammatory study suggests that formulation with cow ghee emulgel is superior to that of all formulation including marketed gel.

 

 

 

INTRODUCTION:

Inflammation is the response of living tissue to damage. Any assaults to living tissue, whether due to physical, chemical, or microbiological origin result in inflammation, manifested by redness(rubor), heat(carol), pain(dolor), swelling (tomour) and loss of function (functio laesa) in acute phase.

 

The inflammatory process involves series of events that can be elicited by numerous stimuli (eg. Infectious agents, ischemia, antigen-antibody interaction and thermal or other physical injury.) Each type of stimulus provokes a characteristic pattern of response that represents a relatively minor variation of them. At the macroscopic level, the response is usually accompanied by the familiar clinical signs of erythema, edema, tenderness and pain. ^[1-2]

 

Emulgels are emulsions, either of oil in water type or water in oil type, which are gelled by mixing with a gelling agent. This research aims for the preparation and evaluation of polyherbal emulgel containing potential herbal anti inflammatory agent viz., tea tree oil, lemongrass oil, ginger oleoresin & capsaicin. The research scheme also focus on the evaluation of prepared polyherbal emulgel and its comparison with the marketed synthetic or herbal anti-inflammatory gel.Regional delivery involves the application of drug to the skin for purpose of treating diseases or alleviating symptoms in deep tissue beneath the application. Here the intent is effectuate the pharmacological action of drug at muscular, vasculature, joints, etc.^[3-4]

 

MATERIAL AND METHODS:

Plant material:^[5-7]

Tea tree oil, lemon grass oil, ginger oleo resin extract and capsaicin extract has been selected for the development of anti-inflammatory formulation. Tea tree oil (Venus chemicals, Pune) Lemon grass oil (Venus chemicals, Pune) Linseed oil(Venus chemicals, Pune)

 

Chemicals:

Menthol (S.D. Fine Chem. limited, Mumbai) Sodium lauryl sulpate (S. D. Fine Chem. limited, Mumbai) Methyl Salicylate (Nice Chemicals, Kerala, India), Glycerol monostearate (Loba Chemie. Pvt. ltd. Mumbai) Triethanolamine (Fisher scientific) Carrageenan sodium salt (Fine chemical industries) Carbopol 940 (Molychem, Mumbai)

 

Animals:

Male wistar albino rats (200-300g each) were maintained under standard animal housing conditions, and used for the anti-inflammatory activity of prepared emulgel formulation. All the animal study was carried out at S.N. Institute of Pharmacy, Pusad having Institutional Animal Ethics Committee, Register No. CPCSEA/729/O2/a/CPCSEA.

 

Method of preparation:

Step 1.:

Aqueous gel base was prepared by dissolving menthol in sufficient quantity of alcohol. This solution was added in 100 ml of purified water. The weighed amount of Carbopol 940 was sprinkled slowly in solution while stirring SLS is added. This solution was kept overnight for complete hydration of carbopol.

 

Step 2.:

 Oil phase was prepared by dissolving all plant material extract in methyl salicylate. The glyceryl monostearate (GMS) was dissolved into warm linseed oil, and this solution was added into above solution to get final oil phase.

 

Step 3.:

This oil phase was then slowly added in the above aqueous carbopol gel base with continuous stirring with using homogenizer. Finally, Triethanolamine was added to the solution with constant stirring, which cause gelling of polymer solution as neutralization of carbopol takes place to get emulgel formulation F1. Cow ghee was used as permeation enhancer added in oil phase of formulation F2.

 

Evaluation of gel:

1. Appearance:

The prepared gel was inspected visually for clarity, colour and presence of any particle. The test is important regarding patient compliance.⁸

 

2. Ph:

pH of gel was determined using pH meter. About 1 gm of gel was stirred in neutralized alcohol till a uniform suspension effected .The volume was made up to 10ml and pH of the solution was measured.⁸

 

 

3. Rheological properties:

1. Determination of viscosity

Viscosity of emulgel was determine by using (LV) Brookfield viscometer (Dial type).As the system is non –Newtonian spindle no.4 is used.⁸

Viscosity was calculated using formula-

                  Dial reading  × factor = viscosity (cps)

 

2. Spreadability:

Ideal gel must have low spreadability values but good consistency. Spreadability of formulation was determined by an apparatus suggested by Multimer et al,⁹ which was fabricated itself in laboratory and used for the study. It consisted of wooden block provided with two glass slides. Lower slide fixed on wooden block and upper slide with one end tied to glass slide and other end tied to weight pan. An excess of gel (2.5gm) between two glass slides and 1000g weight was placed on slides for 5 min to compress the sample to a uniform thickness. Weight was added to pan. The time (seconds) requires to separate the two slides, was taken as a measure of spreadability.

It was calculated using formula:

 

                                  S = m.l / t

Where,

S = spreadability

M = weight tied to upper slide

t = Time taken

l = length of slide 7 cm

Shorter time interval, to cover distance of 7 cm, indicates better spreadability.

 

3. In vitro drug diffusion study:

Topical gel formulations were expected to release the drug quickly, when they are applied to the skin for quick relief. To test the pattern of release of drug from formulation in formulation in vitro diffusion studies were carried out.^10-13

 

In vitro drug diffusion study was carried out as:

1) In vitro drug diffusion through cellulose membrane:

All formulations were subjected to in vitro diffusion through cellulose membrane by using diffusion cell type apparatus. Cellulose membrane was socked in distilled water over night. The membrane was mounted on the diffusion cell apparatus. The system was kept such for 15min to achieve uniformity in temperature.

 

 

 

 

 

 

wt. of std.                                             Abs. of Test          taken              1              6                10         1        % Drug diffuse =     ----------------×  ----------------× ------- ×  ----------- ×   ---------×  --------× 100                                   Abs. of Std.                10            10      Wt. of gel         1           LC                                                                                                   applied

4. Skin irritation:

Ten healthy male and female volunteers were selected for skin irritation testing. 100 mg gel was applied on area of 2 cm² for 6 hours, on the interior surface of upper arm and covered with cotton bandage. After 6 hr the sites were cleaned with acetone and reading are made according to the scale given by Draize et.al¹⁴

 

5. Anti-inflammatory study:¹⁵

“Carragenan induced rat paw edema method” suggested by chi S.C. and Jun H.W.was employed to study the effectiveness of gel formulations. These gels were also compared against the marketed polyherbal gel formulation.          

All the animal study was carried out at S.N. Institute Of Pharmacy, Pusad having Institutional Animal Ethics Committee, Register No. CPCSEA/729/O2/a/CPCSEA.  Albino rats (strain –wistar) of either sex, weighing about 200-300gm were used. Make a mark on both the hind paws (right and left). Just beyond tibiotarsal junction, so that every time the paw is dipped in the mercury column up to fixed mark to ensure constant paw volume. Note the initial paw volume is (both right and left) of each rat by mercury displacement method. Divide the animals into groups of each of 5 animals. Each animal was subjected to carragenan challenge (o.1 ml of 1% carragenan solution injected subplantary) and injection time was noted. Formulations were applied to inflamed paw (0.5 gm of emulgel) by gently rubbing. Rats of control group received only the gel base without drug by the same mode of applications. Paw volumes were noted hourly for 3 hours using plethismometer. The percent inflammation inhibition was determined using formula.

 

V - Vi       % Swelling    = ----------------          ×  100                                   Vi

 

Where, V = paw volume (average after 3hr)

            Vi = initial volume

 

The average paw volume in the group of the drug treated rats was compared with that of control rats and % inhibition of edema was determined using following equation.

 

% swelling of treated   group   % Inhibition = 1 - --------------------------------------                                 % swelling of control group

 

 

 

RESULT AND DISCUSSION:

The objective of the present work is to develop safe and effective anti-inflammatory poly-herbal formulation that could be used in the treatment of inflammation without any side effects. Preliminary studies have indicated that Carbopol 940 can be used as gelling agent. Tea tree oil, lemon grass oil, linseed oil & capsaicin were incarporated for its topical delivery system in the gel form for its anti-inflammatory activity and cow ghee was used as a permeation enhancer.  Two different formulations of with and without permeation enhancer were screened at preliminary level on the basis if solubility of drug, drug release, spreadability, Extrudaility, rheological behavior and anti-inflammatory potential of prepared emulgel. Also best formulation that contains cow ghee as a permeation enhancer was campared with marketed preparation for its anti-inflammatory activity.

 

The gels were subjected for evaluation on the basis of appearance, pH, rheological behavior, in vitro release performance, anti-inflammatory study.

 

In appearance the prepared gel were inspected visually for clarity, colour and presence of any particle, after evaluating both these formulation does not shows the presence of particles with clear appearance and orange in colour.

 

Table No. 1  Appearance of emulgel

Formulation	Clarity	Colour	Presence of  particle
(F1)	Clear	Orange	No
(F2)	Clear	Orange	No

 

The pH of gel was determined using pH meter both the formulation shows the neutral pH.

 

Formulation	pH
(F1)	7.05
(F2)	7.25

 

Viscosity of emulgel was determined by using Brookfield viscometer, As the system is non- Newtonian spindle no.4 is used.

 

Table No.3   Viscosity of formulation (F1) and (F2)

 

Table No.4 Spreadability  study for formulation  (F1) and (F2)

Formulation	Wt. (gm)	Time (s)	Spreadability
(F1)	9 gm	3	21   ±0.2886
(F2)	9 gm	2	31    ± 0.500

Table No.5   Drug diffusion study of formulation (F1) and (F2)                                                                           

Sr no.	Time	% Drug diffuse  (F1)	S.D.	% Drug diffuse  (F2)	S.D.
1	15 min	20.60	± 0.251	40.58	± 0.4788
2	30 min	30.51	± 0.2608	44.40	± 0.4509
3	45 min	57.00	± 1.15	63.95	± 0.4752
4	60 min	58.53	± 0.5150	65.39	± 1.05
5	75 min	61.14	± 1.95	68.20	± 0.2516
6	90 min	85.76	± 0.634	93.96	± 0.7419

 

Fig.No.1  Plot of determination of viscosity of sample( F1)

 

Fig.No.2  Plot of determination of viscosity of sample (F2)

 

From the above graph it was found that the viscosity of sample (F2) was better than sample (F1). From the rheograms it was observed that both gel formulation follows non-Newtonian pseudoplastic flow.

 

The spreadability of gel formulation was evaluated using spreadability test apparatus. Sample (F2) was found to be satisfactory with respect to spreadability.

 

In drug diffusion study better drug diffusion was observed from sample (F2). Addition of cow ghee to this formulation as a permeation enhancer responsible for the better diffusion.

 

When we compare the drug diffusion of sample F1 and F2,  it indicates that sample (F2)  shows higher drug diffusion as compare to sample (F1).

 

Fig.No.3  Graph of in vitro drug diffusion study

 

All the formulation showed no significant skin irritation on intact skin. In no case edema formation was seen .The skin irritation score for all the formulations tested using Draize patch technique was found zero. Thus, indicating skin acceptability of these formulations for topical application.

     

Table No.6 Observation of skin irritation study. 

Formulation	Appearance	Skin irritation
(F1)	Clear	0
(F2)	Clear	0

 

The anti-inflammatory study suggests that formulation with cow ghee emulgel is superior to that of all formulation including marketed gel. The anti-inflammatory study indicated that when used cow ghee in the formulation (F2), the anti-inflammatory effect was comparatively better than the formulation (F1) which was without cow ghee. Hence it is proved that sample (F2) is more effective than Sample (F1) in the treatment of inflammation.

 

Fig. 4   Graph of anti-inflammatory study of emulgel   

Table.7  Determination of anti-inflammatory activity of polyherbal emulgel

Sample	Normal	1 hr.	3 hr.	5 hr.	7 hr.	8 hr.
Control	0.14	0.253	0.31	0.39	0.24	0.246
Test-A	0.16	0.312	0.262	0.28	0.262	0.242
Test-B	0.127	0.235	0.205	0.22	0.212	0.205
Marketed	0.157	0.297	0.272	0.227	0.237	0.235

 

CONCLUSION:

The formulations have satisfactory rheological behavior and their diffusion profile or release pattern is comparable to marketed gel formulation. This study indicates that ginger oleoresin has synergestic action upon Tea tree oil. After addition of herbal anti-inflammatory agent viz.  Tea tree oil to Ginger oleoresin the anti-inflammatory response of the drug was increased. The anti- inflammatory potential of tea tree oil and ginger oleo resin may be elevated by the use of capsaicin and lemon grass oil in the formulation. The better diffusion of drug may be attributed to the use of cow ghee and linseed oil as a permeation enhancer. This emulgel can be the best option for the marketed emulgel containing NSAID’s or SAID’s.

 

ACKNOWLEDGEMENT:

Author hereby acknowledges S.N. Institute of Pharmacy, Pusad for performing anti-inflammatory study. The author would like to thank Principal and Management of IBSS College of Pharmacy, Malkapur for providing necessary facilities.

 

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Received on 19.12.2012       Modified on 26.12.2012

Accepted on 07.01.2013      © RJPT All right reserved