Preparation and Evaluation of Mucilage of Ocimum Basilicum as a Gelling Agent.

 

Shete AS,  Mohite VL and Yadav AV*

Dept. Biopharmaceutics ,Govt. College of Pharmacy, Karad, Dist.- Satara 415124 (MS) India.

* Corresponding Author E-mail: amol.shete@rediffmail.com

 

ABSTRACT

Mucilage from the seeds of Ocimum basilicum (family- labiatae) was separated by centrifugation. Physical characteristics of mucilage such as solubility, swelling index, loss on drying, pH, viscosity were studied. Diclofenac sodium was used as model drug for the formulation of gels and its compatibility with mucilage was proved by FTIR spectroscopy. Hydrogels were formulated with mucilage concentration ranging from 0.5 to 1.5 % and glycerin 30% as plasticizer. Evaluation of spredability parameter suggests the satisfactory rheological behavior of prepared hydrogels. Anti-inflammatory activity of prepared formulations was studied on carageenan induced rat hind paw edema model. The anti-inflammatory activity of prepared formulation was almost identical to that of marketed formulation. In vitro permeation across egg membrane was studied. The gels prepared with 0.75 and 1% of mucilage showed better release and spreadability characteristics. Stability studies of prepared hydrogels at room temperature indicate that they are quite stable.

 

KEY WORDS: Ocimum basilicum, mucilage, hydrogel

 

INTRODUCTION:

The high cost of synthetic polymer and environmental pollution by chemical industry has made the scientist in developing country to enter in to an era, in which plant products serve as alternative to synthetic products because of local accessibility, environmental friendly nature,  lower  prices  and  non  toxic  compared  to imported synthetic products. Today we have number of plant based pharmaceutical excipients such as starch, agar,  alginates,  acacia,  cocoa  butter,  cellulose  etc. These natural excipients are used as binder, disintegrants in tablet, protective colloids in suspensions, thickening agents in oral liquids, gelling agents  in  gels  and  bases  in  suppositories. Similarly many plants  contain  mucilages,  which provide  high concentrations of complex sugars.

 

The seeds of Ocimum basilicum are mucilaginous and cooling, given in infusion in gonorrhoea, diarrhoea and chronic dysentery. A cold infusion is said to relive the after pains of parturition1. Essential oils and fixed oils of seeds are applied as insecticidal fumigant and anti- inflammatory agent.2, 3 Ocimum basilicum seeds swell upon wetting and could serve as natural immobilized source  of  agriculturally based  polysaccharides4. The mucilage contain metal such as chromium, cesium-137 and   strontium   -90   biosorption   property.5,6    Hence present study was planned to formulate diclofenac sodium hydrogel using Ocimum basilicum mucilage as a gelling agent and to study its characteristics.

 

MATERIALS AND METHODS:

Ocimum  basilicum  seeds   were   purchased  from  Green pharmacy, Pune. Diclofenac sodium was obtained as a gift sample   from   Cipla   Pvt.Ltd.   (Goa).   Carageenan   was borrowed from Himedia Laboratories. All other ingredients were   of   analytical   grade   and   purchased   from   Loba chemicals, Mumbai.

 

Isolation of mucilage from Ocimum basilicum seeds Ocimum basilicum seeds (33 g) were soaked for 12 hr in distilled water (1100 ml). The swollen material was passed through syringe and centrifuged at 4000 rpm for 20 min. to separate the mucilage. The separated mucilage was washed several times with distilled water and dried at 40-450C and passed through sieve No.120 and stored in a desiccator until used for further studies.

 

Physiochemical properties of dried mucilage

The physiochemical properties such as solubility, pH and viscosity of dried mucilage were determined at 20°C. The loss on drying, total ash content, acid  insoluble ash and water soluble ash were determined according to Indian Pharmacopoeial Procedure.7 (Table-1)

 

Determination of gelling concentration of mucilage

A  different  concentration of  dried  mucilage  powder  was mixed with distilled water by using laboratory stirrer and the gel forming concentration was found out by studying viscosity of preparation.

 

Preparation of hydrogels

Hydrogels were prepared by using different concentrations of mucilage. Diclofenac sodium was dissolved in distilled water  and  then  different  concentration  of  mucilage  was added as gelling agent, glycerin, menthol, benzoic acid and eucalyptus oil were added as plasticizer, penetration enhancer,  preservative  and  flavoring  agent respectively.  pH  was  adjusted  by  using triethanolamine. As shown in table-2 four batches of temperature.

 

Table.1   Physico-chemical properties of mucilage

Parameters

Results

Solubility

Soluble in cold water and hot water forming viscous colloidal solution

Swelling index

11.5

pH

6.8

Viscosity  (0.15%w/v solution)

1.4743 cps

Specific  gravity  (g/ml of 0.15%w/v solution)

0.9975

Loss on drying

11.8%

Total ash

7.72

Acid insoluble ash

0.57%

Water soluble ash

6.532%

 

Evaluation of hydrogels

Drug- mucilage interaction study

The physical mixture of drug and  mucilage powder was subjected to infrared spectroscopic study to determine   the   interaction.   An   IR   spectrum   was recorded   using   FTIR   spectrophotometer   JASCO FT/IR- 5300.

 

Table.2    Formulations.

Ingredients

F1

F2

F3

F4

Powdered mucilage (%)

0.5

0.75

1

1.5

Diclofenac sodium(%)

1

1

1

1

Glycerin (%)

30

30

30

30

Benzoic acid (%)

0.1

0.1

0.1

0.1

Triethanolamine

q.s

q.s

q.s

q.s

Eucalyptus oil

q.s

q.s

q.s

q.s

Distilled water

q.s

q.s

q.s

q.s

 

Determination of spreadability

Spreadability of formulation was determined by an apparatus  suggested  by  Multimer  et  al.  which  was fabricated  and  used  for  the  study.  It  consisted  of suitably diluted and absorbance was measured at 276 nm by spectrophotometer (Shimadzu 1700 Japan).

 

Figure 1   Drug release profile of formulation F1, F2, F3 and F4

Anti-inflammatory activity

Albino rats of wistar strains of either sex weighing between 140-170 gm were selected for the study .The animals were divided into six groups each containing four animals.

Group 1- Control; Group 2- Marketed formulation; Group 3- F1; Group 4- F2; Group 5- F3; Group 6- F4 Anti-inflammatory activity was evaluated using carrageenan induced rat hind paw edema method. TheGroup-1 served as control. 50mg of respective formulation was applied to the paw one hour before carrageenan injection (0.1ml 1% solution) subcutaneously. Paw volume of each formulation was evaluated in terms of % inhibition of edema using formula

 

% Inhibition of edema = (1-VT/VC) 100

Where VT = Mean inflammation of test group

VC = Mean inflammation of control group

 

Figure 2   Stability study profile formulation F1,F2, F3 and F4

 

Stability studies:

Wooden block on which the glass plate was fixed. 2.5 gm of gel was placed between two slides and 1000 gm weigh was placed over it for 5 minuites to press the sample to uniform thickness. 80 gm weight was placed in the pan. The time (in seconds) required to separate the two slides were taken as a measure of spreadability. Shorter time to cover the distance of 7.5 cm indicate better spreadability.

Drug content uniformity

Drug  concentration  in  hydrogel  was  measured  by spectrophotometric determination known amount of hydrogel  was  dissolved in  phosphate buffer  pH  7.2

 

In vitro permeation study across egg membrane

Egg  membrane was used  for the  permeation study.9   The separated membrane was soaked in pH 7.2 phosphate buffer prior to use. The membrane was placed on the transdermal permeation study apparatus (KC diffusion cell) to carry out the in vitro diffusion studies. The membrane was clamped on the diffusion cell and hydrogel applied on the membrane. One gram of gel equivalent to 10 mg drug placed on membrane, for evaluation of the drug permeation rate and extent of permeation, 20ml of phosphate buffer of pH 7.2 maintained  at  370   C  was  used  .The  fluid  was  stirred magnetically at 50 rpm. Aliquots were withdrawn at 1, 2, 3, 4 and 5 hours after the commencement of drug permeation experiment. Aliquots were replaced with an equal volume of fresh buffer. After suitable dilutions samples were analyzed spectrophotometrically (Shimadzu  1700  Japan)  at  276  nm  after  suitable dilution percentage drug release was determined.

 

Stability study

Hydrogel samples were filled in aluminum collapsible tubes. Filled collapsible tubes were stored at room temperature for three months and analyzed for physical characteristics, drug Content and synerisis.10

 

RESULTS:

Mucilage was obtained from Ocimum basilicum seeds by soaking them in water; a 26% yield of mucilage was obtained. The physiochemical properties of mucilage were studied and are shown in table1. The gelling concentration of mucilage lies between 0.5 to 1.5%. The  pH  of  the  mucilage  is  6.8,  which  is  ideal  for topical application.

 

Table.3   Spreadability time (n=3)

Formulations

Spreadability time (seconds) ± S.D

Marketed preparation

21 ± 2

F1

17 ± 3

F2

20 ± 1

F3

22 ± 4

F4

26 ± 3

 

IR spectra mixture of mucilage powder and drug showed all IR peaks of drug and no new peak was observed. It indicates that there is no evidence of interaction between anionic drug and anionic mucilage powder. Order of spreadability F4 > F3 ≈ Marketed preparation ≈ F2 > F1. Mucilage concentration of 0.75 and 1% showed spreadability time close to marketed preparation. (Table-3). Percentage drug content was found to be in the range of 99.00±1.02 to 100±0.47. It showed uniform distribution of drug in all formulations (Table-4). The anti-inflammatory activity of our formulations is almost equivalent to that of marketed preparation as observed in percentage inhibition of rat hind paw edema over a period of 6 hours (Table-5).

 

The in vitro diffusion profiles of Diclofenac sodium gels containing different Concentration of mucilage are shown in Fig.1. The gels prepared with 0.75% and 1% showed constant zero order drug release profile over a period of 7 hours. The stability of gels was studied at room temperature for 3 months. Study revealed that, there was drying of formulation F1 containing 0.5% of mucilage was observed.   Other formulations were physically stable in terms of     weight, uniformity in drug content (Fig.2) and absence of synerisis.

 

formulations because of its ideal characteristics such as low cost,   good   release  profile,  rheological  property,  water soluble  nature,  physical  stability  and  compatibility  with drug. From the results of stability study gels were stable at room temperature.

 

In conclusion present study dictates a  further accelerated stability testing and study in human volunteers is required to establish mucilage as a potential gelling agent.

 

Table.4   Percentage drug content.

Formulations

% Drug content ± S.D.

F1

99.00±1.02

F2

100±0.47

F3

99.00±0.85

F4

100±0.33

 

ACKNOWLEDGEMENTS:

Authors are thankful to Principal Dr. S. B. Bhise (Govt.

College of Pharmacy, Karad.) for providing facilities for our research work, Mr. Tekawade for assistance in animal handling.

 

Table.5   Cumulative %  inhibition of paw edema over a period of 6 hours.

Formulations

Cumulative % inhibition ± S.D

Marketed preparation

80.8  ± 2.12

F1

74.4 ± 4.45

F2

78 .2 ± 3.52

F3

76.5 ± 1.23

F4

75.3 ± 2.56

 

DISCUSSION:

In the present study, Ocimum basilicum mucilage may

be used as gelling agent for the development of gel

 

REFERENCES:

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3.     Singh S. Comparative evaluation of anti-inflammatory potential of fixed  oil of different species  of Ocimum and  its possible mechanism of action. Indian J Exp Biol. 1998; 36: 1028.

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7.     Indian Pharmacopoeias. New Delhi. 1985, A-73, A-88.

8.     Winter  CA,  Risley  EA  and  Nuss  GW.  Carrageenan  induced edema in hind paw of rats as assay for anti-inflammatory drugs. Proc Soc Exp Biol. 1962; 111: 544.

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Received on 17.06.2008    Modified on 22.06.2008

Accepted on 30.08.200 © RJPT All right reserved

Research J. Pharm. and Tech. 1(3): July-Sept. 2008; Page 201-203