Evaluation of Suspending Property of Fruit Mucilage of Abelmoschus esculentus. (L) Medie


K.A. Kedar*, U.V. Marakana and P.D. Chaudhari

Modern College of Pharmacy, Nigdi, Pune-411044.

*Corresponding Author E-mail: kk_pharma20@rediffmail .com



The present study was undertaken to evaluate the mucilage obtained from the fruit of Abelmoschus esculentus (Linn) Medie as a suspending agent. The main parts used in the plant are leaves, flowers, fruit and seed. The plant was found to contain mucilage and in our studies we have identified the mucilage in the fruit of the plant.

A suspension of Zinc oxide was used to yield a 20% w/v suspension in water using mucilage as suspending agent and it is evaluated for its stability using the parameters like sedimentation volume, separation volume, redispersibility, viscosity and pH. The suspending effect of abelmoschus mucilage was compared with Zinc oxide suspensions prepared in water using suspending agent such as sodium CMC and tragacanth. The result obtained indicated that the abelmoschus mucilage could be used as a suspending agent. It has low rate of sedimentation, high viscosity, basic pH and is easily redispersible. These effects were comparable with that of the standard suspending agents like sodium CMC and tragacanth. From the observation extracted mucilage from fruit of Abelmoschus esculentus has the potential as a suspending agent even at low concentration and can be used as a pharmaceutical adjutant.


KEYWORDS: Abelmoschus esculentus, mucilage, suspending agent, zinc oxide



Mucilage and gums are use in various industries because of low cost, easily availability and important properties which they confer on product1,2. In the modern era also they are widely used in the pharmaceutical industries as thickeners, water retention agents, emulsion stabilizers suspending agents, binders and film formers3,4. Mucilage are generally normal products of metabolism formed with in the cell and are the other pharmaceutically important polysaccharides derivative. Mucilage are physiological product and form colloidal solutions5.


The plant Abelmoschus esculentus. (Linn) Medie constitute the much relished vegetable, and commonly known as the Okra, bendee, gombo. The main parts used in the plant are leaves, flowers, fruit and seed, but researchers have explored that even the immature capsules in the form of infusion gratefully used in dysentery and diarrhea; in acute inflammation6.


The plant was found to contain mucilage and in our studies we have identified the mucilage in the fruit of the plant. The major constituents of the fruits free from seeds contain the amino acids such as glutamic acid, argenine, histidine, lycine, cerine and alanine besides the sugars D-glucose and glucosamine7.

The Major constituents of the mucilage is an acidic polysaccharide composed of L- rhamnose: D-galactose: D-galactouronic acid: D-glucuronic acid in the molar ratio of 5:8:3:28,9. There are reports available on the successful use of mucilage of Abelmoschus esculentus. (Linn) Medie as a suspending agent at different concentration by using paracetamol suspension10. The present work is an attempt to investigate this mucilage in minimum concentration as a suspending agent in pharmaceutical formulations.



Plant material:

Fresh fruit of plant was purchased from local market, Moshi, India and authenticated by Botanical Survey of India, Pune (Voucher specimen no. UVMAE1). Fruits were washed, dried and powdered and passed through sieve No. 40.


Isolation of mucilage:

Dried fruits were coarsely powdered (500g) and were macerated with 50 times their weight of water for 24h. The extract was then pressed through muslin cloth. To the filtrate, ethanol was added in 1:2 proportions to precipitate out mucilage. The mucilage (17%w/w) so obtained was then subjected to air drying for sufficient period of time11.


Phytochemical Examination:

Preliminary tests were performed to confirm the chemical nature of isolated mucilage. Powder of mucilage showed red colors with ruthenium red so the isolated product was mucilage. It also shows positive result with general molish test indicates presence of carbohydrate. Test solution does not give response to Fehling and Benedicts test so the type of sugar was non reducing12.


Evaluation of suspending property of mucilage:

There are number of consideration in the development and preparation of Suspension. There are some desirable qualities that are needed for ideal suspension e.g. chemical stability, permanency of preparation, esthetic appeal of preparation along with retaining efficacy. A suspension should settle slowly and should be readily redispersed, particle size of suspended material remain constant, it should pour readily are some other ideal characteristics. The sample of mucilage was evaluated for its suspending properties like separation rate, degree of flocculation and redispersibility.


Preparation and evaluation of suspension:

Zinc oxide which was sieved through sieve No 100 and retained on sieve No 200 was used to yield a 20% w/v suspension in water using tragacanth, sodium CMC and mucilage. Using each suspending agents suspensions were produced with two concentrations (0.5 and 2.0% w/v). For making suspensions, zinc Oxide was first levigated with glycerin (1:1). Then a weighed amount of these suspending agents were added and triturated and finally the volume was made up with distilled water. The suspensions contained 0.1% w/v benzoic acid as a preservative. All the suspensions were deflocculated. To determine the degree of flocculation we have also prepared flocculated suspensions using a flocculating agent, potassium dihydrogen phosphate (0.004 mol)13.


Sedimentation volume:

Sedimentation volume is the most important parameter in the evaluation of suspension stability. Sedimentation volume F is the ratio of the ultimate height (Hu) of the sediment as a suspension settles in a cylinder under standard conditions to the initial height (Ho) of the total suspension in a graduated cylinder in an undisturbed position for a definite period of time and noting the value of Hu and Ho.14


Rate of separation:

The rate of separation of the suspensions were studied by keeping 50 ml portion of each suspensions in a Stoppard measuring cylinder and stored undisturbed at room temperature. The separation of clear liquid was noted at intervals of 5 days up to 45 days. The separation ratio was calculated using the formula

Rate of separation n=Hs/Ho,


Where, Hs is the height of clear liquid and

Ho is the original height of the sample.




Redispersibility of a suspension can be estimated by shaking the suspension with the help of a mechanical device, which stimulate the motion of human arm during shaking11. Fixed volume (50ml) of the each suspension was kept in calibrated tubes, which were then stored at room temperature for various time intervals (5, 15, 25 days). At regular intervals (5, 15, 25 days) one tube was removed and shaken vigorously to redistribute the sediment and the presence of deposit if any is noted. The time taken to redisperse the sediment suspension was recorded14.


Determination of pH and viscosity:

The pH and viscosity are important parameters mostly check for stability of suspension. The pH of the suspension was determined by using pH meter and same was determined at interval of one week for 21 day and their viscosity was determined by using Brookfield viscometer. The values expressed are mean+ SD of three observations14.



Mucilage was extracted from fruit of Abelmoshchus esculentus and yield obtained was 1gm/kg. On treatment of mucilage with ruthenium red, it showed red colors confirming the obtained product as mucilage. A violet ring was formed at the junction of two liquids on reaction with molish reagent indicating the presence of carbohydrates. Mucilage could not reduce Fehling solution, So the sugar present were non reducing sugars. Mucilage gave purple coloration on treating with ninhydrin reagent indicating the presence of amino acid.


Evaluation of mucilage as suspending agent was done by sedimentation volume, separation volume, pH studies and redispersibility tests. Sedimentation rates were determined for Abelmoshcus mucilage comparing with tragacanth and sodium CMC are shown in table 1 and graph 1.


The dispersed particles of Zinc oxide prepared using Abelmoschus mucilage was found to be sediment at lower rate than those prepared with tragacanth and slightly higher than that of Sodium CMC.


Fig. 1


Determination of suspending property of Abelmoschus mucilage:

The separation rate was higher at low concentration and dependent on degree of flocculation but less than that of tragacanth and CMC. Rate of separation was more in flocculated system than deflocculated. Degree of flocculation was found to be more at low concentration (0.5%) and gradually decreased with increasing concentration of mucilage.



Table no: 1: Determination of suspending property of Abelmoschus mucilage

Time in minutes


(Zinc oxide) (F)

Zinc oxide + Abelmoschus mucilage (F)

Zinc oxide + Tragacanth (F)

Zinc oxide + Sodium CMC (F)




































Sedimentation volume (F)= Hu/Ho


Table 2. Determination of pH, Viscosity and redispersibility


pH after storage for (Centipose)


Rate of redispersibility (Cycles)


0th day

7th day

14th day

21 st day

5th day

15 day

25 day










Sodium CMC









Abelmoshcus mucilage











Fig 2- Comparison of sedimentation properties of suspending

Agents at 0.5 % concentration level



pH studies for the suspension prepared with Abelmoshcus mucilage was for 3 weeks. The change in pH can be attributed to hydrolysis or microbial decomposition. Redispersibility test was performed for 3 weeks using Abelmoshcus mucilage, tragacanth and sodium CMC. Since the suspension produces sediment on storage, it must be readily dispersible so as to ensure the uniformity of the dose. Less is time taken to redispersed the sediment, better is the redispersibility. The suspention prepared by Abelmoshcus mucilage showed better redispersibility than tragacanth and sodium CMC on 5h and 15th day. (Table 2)


Natural products research continues to be an important part of the drug discovery process. The main advantages of natural products as a source of lead compounds is the tremendous molecular diversity found in nature. It was already reported that the natural drugs can be use as an excipients in various pharmaceutical industry. It was already proved that natural products are safer than that of synthetic drugs15. In this aspect, the Abelmoschus fruit mucilage tested for suspending effect has shown promising result at minimum concentration and the effect were comparable with that of the standard suspending agents like tragacanth and CMC. Toxicity is not concern for this mucilage because the effective concentration of the suspending agents in conventional dosage form normally does not exceed 2% of the formulation13.

From the observation it is concluded that the extracted mucilage from fruit of Abelmoschus esculentus has the potential as a suspending agent even at low concentration and can be used as a pharmaceutical adjutants.



Authors are thankful to Dr. P. G. Diwakar for taxonomical identification of the plant material.



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Received on 12.11.2009 Modified on 20.03.2010

Accepted on 31.05.2010 RJPT All right reserved

Research J. Pharm. and Tech.3 (4): Oct.-Dec.2010; Page 1036-1038