INTRODUCTION:

Hibiscus syriacus L. (Rose-of-Sharon) is valued for large flowers produced in summer when few other shrubs bloom. It is useful as a garden accent due to its strict, upright habit. The open, loose branches and light green leaves make Rose-of-Sharon ideally suited to formal or informal plantings, and with a little pruning makes an attractive, small specimen tree. The plant grows in sun or partial shade and in any soil. Rose-of-Sharon grows 8 to 10 feet tall and spreads 4 to 10 feet. The growth rate ranges from slow to moderate, and transplanting is easy. Several roots are usually located just beneath the soil surface. The insects can be dislodged with high pressure water sprays from the garden hose or controlled by pinching off the part of the twig with the insects. Over-fertilizing increases aphid infestations. The single or double flowers are in shades of red, pink, white and purple, depending on the cultivar. Individual flowers stay open for one day and close at night. Since plants bloom on new growth, shaping or pruning can be done at any time.

However, pruning is usually not required since the plant grows slowly and keeps a tight upright form. ¹

Medicinal use of Hibiscus syriacus:

H. Syracuse (rose of Sharon). Roselle is said to lower fevers and high blood pressure, relieve coughs, increase urination, hepatoprotective², and kill bacteria. China rose is used primarily for respiratory problems, but also for skin disorders and to treat fevers. Rose of Sharon is used externally as an emollient to soften and soothe the skin, as well as used internally for digestive disorders. Presently more attention on paid to CNS active, cytoprotective, immunomodulators and chemotherapeutic plant products. Nutraceutics have opened up an entirely new field for exploration and in the near future, dietary modulations of disease mat immerge as an alternative mode of therapy. At the same time a decreasing trend has been noticed towards evaluation of plants for their effect on the autonomic nervous system or fertility control.

Hibiscus, especially white hibiscus, is considering to have medicinal properties in the Indian traditional system of medicine, Ayurveda. Roots make various concoctions believed to cure various ailments.³

Herbal gel:

A gel is a semisolid system of at least two interpenetrating phases: a gelling agent and a liquid. Gels that contain water are called hydro gels, while those that contain an organic liquid are called organ gels. Hydro gels, in the broad sense, include the matrix of water – soluble materials such as cellulose derivatives and natural gums. Gels are used pharmaceutically as lubricants and as carriers for spermicidal agents 10 and other drugs for their local effects and percutaneous absorption. Herbals are the oldest form of primary health care, which were used by all cultures throughout history. They were an integral part of the development of modern civilization.⁴

Application of the herbal gel:

Half a gram of the herbal gel, as the test substance, was applied to a an area of approximately 6 cm² of skin and covered with a gauze patch, The patch was loosely held in contact with the skin by means of a suitable semi-occlusive dressing for 4 hours and was then removed.

At the end of the exposure period, i.e. 4 hours, residual test substance was removed without altering the existing response or the integrity of the epidermis.

Observations were recorded an hour after the removal of the patch. Control animals were prepared in the same manner and 0.5 gram of the gel base, i.e gel formulated using all the ingredients except the herbal mixture, was applied to the control animals and observations were made similar to the test animals.⁵

MATERIAL AND METHODS:

Present study is based on traditional knowledge of plant. The study reveals the potency of the formulation and evaluation of herbal gel containing methanolic extract of hibiscus Syracuse. Criteria of selection of plant for our work were based on:

The present study deals with the “Formulation and Evaluation of Herbal gel containing Methanolic Extract of Hibiscus syriacus”. Methanolic extract of Hibiscus syriacus is preparing by hot perculation method and evaluate the herbal gel on deferent parameter.

Selection of plant:

Drug discovery from medicinal plants has evolved to include numerous fields of inquiry and various methods of analysis. The process typically begins with a botanist ethanopharmacologist who identifies the plant of interest. Collection may involve species with known biological activity.On the basis of intensive literature survey Hibiscus syriacus were selecting for present study.

Collection of plant materials:

The leaves of Hibiscus syriacus L. was collected from the month of august-September from the Garden of Jawaharlal Institute of Technology and G. R. Y. Institute of Pharmacy Vidya Vihar Borawan District Khargone Western Nimar region of Madhya Pradesh,

Authentication of plant:

The plant Hibiscus syriacus L. was identified and authenticated by Dr S.K. Mahajan, (Retd) Botanist from Government College, Khargone Madhaya Pradesh. The herbarium of the plant specimens were prepared and deposited in the Department of Pharmacognosy, G. R. Y. Institute of Pharmacy Vidya Vihar Borawan district Khargone Madhaya Pradesh, India, under voucher no. G.R.Y.I.P. 43.

Preparation of extract:

The leaves were initially separated from the main plants body and rinsed with distilled water and shade dried and then homogenized into fine powder and stored in air tight bottles. It was then passed through the 40 mesh sieve Dried and powered plant defatted firstly to remove fatty material for this purpose 1000 g of weighed powered plant of Hibiscus syriacus L. was packed in Soxhlet apparatus and extracted with petroleum ether at 60-80°c for 36 hrs and completion of extraction was confirmed by discoloration of the solvent. The marc was removed and dried then it was subjected to continuous hot extraction with methanol in soxhlet apparatus for 36 hrs and completion of extraction was confirmed by discoloration of the solvent. The methanolic leaves extract of Hibiscus syriacus L. yielded greenish brown then it were filtered with the help of muslin cloth. The supernatant was collected and solvent distillations apparatus evaporated the solvent and concentrate the extract in reduce pressure. ¹

Standardization:

The evaluation of a crude drug involves the determination of identity, purity and quality. Purity depends upon the absence of foreign matter whether organic or inorganic, while quality refers essentially to the concentration of the active constituents in the drug that makes it valuable to medicine. The following standardization parameters were evaluating to obtain the qualitative information about the purity and quality of Hibiscus syriacus. The results are showing in Table No.1

Determination of foreign matter:

Foreign matter in herbal drugs consists of either parts of the medicinal plant or it may be any organism, part or product of an organism. It may also include mineral admixtures not adhering to the medicinal plant materials e.g. soil, stones, dust etc. The specified quantity of plant material was spread on a thin layer of paper. By visual inspection and by using a magnifying lens (5X or 10X), the foreign matters were picked out and the percentage was recorded.⁶

Determination of physicochemical parameter:

Ash values:

Ash values are helpful in determining the quality and purity of a crude drug, especially in the powdered form. The objective of ashing vegetable drugs is to remove all traces of organic matter, which may otherwise interfere in an analytical determination. On incineration, crude drugs normally leave an ash usually consisting of carbonates, phosphates and silicates of sodium, potassium, calcium and magnesium. The total ash of a crude drug reflects the care taken in its preparation. A higher limit of acid-insoluble ash is imposed, especially in cases where silica may be present or when the calcium oxalate content of the drug is very high.⁶

Total ash value:

Accurately weighed (about 20g) of the powdered drug was taken in a tare silica crucible. Incineration was done at a temperature not exceeding 500 0C for 4 h, until free from carbon. The crucible was cooled and weighed. The percentage of ash was calculated with reference to air-dried drug.⁶

Acid insoluble ash value:

The ash was boiled for 5 min with 50 ml of 2 M HCl. The solution was filtered and the insoluble residue collected on an ash less filter paper, washed with hot water and ignited in a tare crucible at a temperature not exceeding 500○C for 4 h. cooled in a desiccators and weighed. The percentage of acid insoluble ash with reference to the air-dried drug was calculated. ⁶

Extractive values:

Alcohol soluble extractive value:

10 gm accurately weighed, macerated coarse powdered drug was mixed with 100 ml of alcohol (90%v/v) in a stopper flask for 24 h, shaking frequently during first 6 hours. The solution was filtered rapidly through filter paper taking precaution against excessive loss of alcohol. 25 ml of alcoholic extract was evaporated to dryness in a tared dish and weighed. The percentage w/w of alcohol soluble extract with reference to the air-dried drug was calculated. ⁷

Water-soluble extractive value

10 gm accurately weighed of the preparation in a 250 ml of beaker heat to boiling for 10 min. to remove the alcoholic and volatile matters and adjust the volume with distilled water and filter through filter paper in a evaporating dish evaporate on a water bath and dry in a vacuum dryer for 30 min. cool in a desiccator till constant weight calculate the percentage by w/v.⁷

Ether soluble extractive value:

10 gm accurately weighed, macerated coarse powdered drug was mixed with 100 ml of ether (90%v/v) in a stopper flask for 24 h, shaking frequently during first 6 hours. The solution was filtered rapidly through filter paper taking precaution against excessive loss of water. 25 ml of ether extract was evaporated to dryness in a tared dish and weighed. The percentage w/w of ether soluble extract with reference to the air-dried drug was calculated.⁸

Table 1: Determination of physicochemical parameter

S. No.	Physico-chemical parameter	*Hibiscus* *syriacus*
1.	Foreign matter	Nil
2.	Moisture content	6.85%
3.	Total ash values	17.75%
4.	Acid insoluble ash values	27.32%
5.	Sulphated ash value	17.44%
6.	Alcohol soluble extractive	13.70%
7.	Water soluble extractive	12.00%
8.	Ether soluble extractive	4.00%

Gel Formulation:

The gel based on synthetic gelling agents was prepared. Weighed amount of gelling agents were placed in known amount of distilled water. After complete dispersion, the polymer solution was kept in dark for 24 hours for complete swelling. Accurately weighed amount of drugs were dissolved in a specified quantity of suitable solvent. The drug solution was added slowly to the aqueous dispersion of polymer with the help of high speed stirrer (500 rpm) taking precaution that air did not entrap. Finally, the remaining ingredients were added to obtain a homogeneous dispersion of gel.^8,9

Evaluation of Gels:

Gels were evaluated for their clarity, pH, viscosity, spreadability, extrudability, drug content, in vitro diffusion studies by the standard procedure. All studies were carried out and average values were reported.

Clarity:

The clarity of various formulations was determined by visual inspection and it was graded as follows; turbid: +, clear: ++, very clear (glassy): +++.

pH measurement:

The pH of the gel was determined by using a digital pH meter (Systronics pH meter type 335) 5gm gel dissolved in 50 ml water and pH was determined by dipping the glass electrode completely into gel solution system so as to cover the electrode. Then instrument reading in terms of pH are tabulated in the 2.5 grams of gel was accurately weighed and dispersed in 25 ml of distilled water. The pH of dispersion was measured by using digital pH meter. ⁸

Homogeneity:

All developed gels were tested for homogeneity by visual inspection after the gels have been set in the container for their appearance and presence of any aggregate. ⁹

Table No. 2 formulation development of Herbal Gel

S.no.	Formulation No.	Carbapol (gm)	Propylen glycone (ml)	Ethanol (ml)	Triethalamine (ml)	Water (ml)	Methnolic extract (gm )
1.	F1	2.5	5	12.5	1	q.s.	0.4
2.	F2	3.75	5	12.5	1	q.s.	0.8
3.	F3	5.00	5	12.5	1	q.s.	1.2
4.	F4	6.25	5	12.5	1	q.s.	1.6
5.	F5	7.5	5	12.5	1	q.s.	2.0
6.	F6	8.75	5	12.5	1	q.s.	2.4

Spreadability:

It was determined by wooden block and glass slide apparatus for the determination of spreadability, excess of sample was applied in between two glass slides and they were compressed to form a uniformly thick layer of gel. The upper slide was then pulled apart horizontally with a string and pulley system. Initially 10 gm weight was tied to the thread and left for 5 minutes, and then the weight was increased by 1 gm at every step. The time required to separate the two slides, i.e. the time in which the upper glass slide moves over the lower plate was taken as measure of Spreadability (S).

Spreadability was calculated by using the formula:

S = ML/T

Where, S = Spreadability M = Weight tied to upper slide L = Length moved on the glass slide T = Time taken to separate the slide completely from each other.¹⁰

Viscosity measurement:

The measurement of viscosity of the prepared gel was done with a Brookfield Viscometer. The gels were rotated at 0.3, 0.6 and 1.5 rotations per minute. At each speed, the corresponding dial reading was noted. The viscosity of the gel was obtained by multiplication of the dial reading with factor given in the Brookfield Viscometer catalogues. ¹¹

Stability studies:

Stability is defined as the extent to which a product retains its efficacy within specified limits throughout the period i.e. shelf life. All the selected formulations were subjected to a stability testing for 6 weeks at room temperature. All selected formulations were analyzed for the change in pH, Spreadability, homogeneity or drug content by procedure stated earlier. ⁹

RESULTS AND DISCUSSIONS:

The herbal gel was greenish in color and translucent in appearance and gave smooth feel on application which was maintained after tested stability study. pH was maintained throughout the study which was found 6.5–7.2. Spreadibility was also measured and found to be less variation. The initial viscosities of developed gels were measured using Brookfield viscometer with spindle. Further stability test for two months has been carried out and results revealed that 5% carbopol 934 gel showed better stability than other carbopol 934 formulations. Initial viscosity for gel containing 5% carbopol 934 were 2325 cps and after stability study there were not much variation. In vitro drug release of different formulations it was found that carbopol 934 (5%) gels show highest drug release, better pH, clarity, spreadability and homogeneity. Also the In formulation optimization process the studies on their release properties have revealed that the carbopol 934 (5%) gel shows highest release rate in comparison to other concentration.

During the trial, the excipients concentrations of carbapol and sodium CMC are gradually increasing and decreasing as a result several problems are coming like homogeneity, spreadibility and viscosity. These problems occured in some of the batches (F1, F2, F5 and F6) of polymer carbopol 934 based gel containing Hibiscus syriacus. Hence, these batches were discarded and remaining batches (F3and F4) were considered for further study.

The developed herbal gel was greenish in color, translucent in appearance and showed good homogeneity with absence of lumps. The formulated F3 preparation was much clear and transparent as compared to F4. The values of spreadability indicate that the gel is easily spreadable by small amount of shear.

Spreadability of formulated gels (F3, and F4) were 23.08, 21.06g cm/sec. Hence spreadability of F3 formulation was good as compared to F4 formulation. During the accelerated stability studies the appearance was clear and no significant variation in pH was observed and spreadability is 20.22 in F3 formulation after 3 months where as spreadability in F4 was 17.82. pH also maintained throughout the study which was found 6.5 – 7.2. The initial viscosities of developed gels were measured using Brookfield viscometer with spindle. The topical gel thus formulated was non-irritant upon application on to the skin.

CONCLUSION:

Natural remedies are more acceptable in the belief that they are safer with fewer side effects than the synthetic ones. Herbal formulations have growing demand in the world market. It is a very good attempt has made to establish the herbal gel containing Hibiscus syriacus extract. The studies revealed that the developed single herbal formulation F3 consisting Hibiscus syriacus extract comparatively better than later other formulations but all the formulations were non irritant though further pharmacological screening were may implied to test and investigate the safety profile of formulated gel to treat various inflammation of skin.

Table 3: Evaluation of gels.

S.No	Formulations	Clarity	pH	Homogeneity	Spreadability	Viscosity (cps)	Colour	Irritability	Appearance
1.	F1	+++	6.5	Good	26.04	1864	Greenish	No irritation	Homogeneous
2.	F2	+++	6.4	Good	24.00	2133	Greenish	No irritation	Homogeneous
3.	F3	++	6.6	Good	23.08	2325	Greenish	No irritation	Homogeneous
4.	F4	+++	6.7	Good	21.06	2467	Greenish	No irritation	Homogeneous
5.	F5	++	6.9	Good	23.05	2580	Greenish	No irritation	Homogeneous
6.	F6	+	7.2	Good	19.09	2721	Greenish	No irritation	Homogeneous