Screening and optimization of an aqueous based natural polymer

 

Banhishikha Kar, Ayan Kumar Kar

Department of Pharmaceutics, Calcutta Institute of Pharmaceutical Technology & AHS, Banitabla, Uluberia, Howrah, West Bengal, India-711316.

 

ABSTRACT:

The recent study includes the extraction and characterization of tamarind gum, Tamarindus indica from Tamarind seeds which is used in the pharmaceutical, textile and food industries as a mucoadhesive polymer. It belongs to a Leguminosae family. Aim of the present work is to establish that the Tamarind gum use as a natural polymer. Water based extraction procedure was used to extract polysaccharide from tamarind seed. For characterization of extracted gum, different Pharmacopoeial methods like micromeritic properties, solubility, DSC, FTIR, organoleptic properties and pH is studied. The extracted gum is insoluble in organic solvents like ethanol, acetone, methanol, ether etc as well as cold water which formed the basis of separation and procurement of the gum. It is only soluble in hot water. It yields a highly viscous colloidal solution at temperature above 85⁰ C. It is also found that extracted tamarind gum has good flow properties and pH is 6.6. The tamarind seed polysaccharide is a pH sensitive polymer which being activated only in basic pH. It can be concluded from the whole study and their evaluation that tamarind seed polysaccharide can be an important pharmaceutical excipient which can be used in solid dosage form without any irritation. Obtained results also showed that extracted seed polysaccharide may be used as natural gelling agents in different pharmaceutical formulations. Future works will focus on the quantitative analysis, biological activity and possible use of Tamarind Seed Polysaccharide as a drug delivery system.

 

 

 

 

 

 

 

 

 

 

 

 

INTRODUCTION:

In the present investigation it shows that plant polysaccharide have been useful for the construction of specific drug delivery systems. Natural polymers are obtained in the form of macromolecules. The natural gums are biodegradable, nontoxic and biocompatible in nature and swells when comes in contact with the aqueous media so it has been used in the preparation of sustained release or controlled release types of dosage form.^[1] In recent years, plant derived polymers have mucilage can occur in high concentrations in different evoked tremendous interest due to their diverse pharmaceutical applications as a diluents, binder disintegrant in solid dosage forms, thickeners in oral liquids formulations, protective colloids in suspensions, gelling agents in gels and bases in suppository.^[2]

 

In the present investigation it shows that plant polysaccharide have been useful for the construction of specific drug delivery systems.^[3] The polysaccharide that is present in tamarind gum is known as tamarind seed polysaccharide (TSP). Natural gums and polymers (TSP) comes in contact with water to form gel layer on the surface of the system from that controlled the release of the drug.^[4] Tamarind gum  have been wildly used as emulgents and thickeners in cosmetics suspensions as film-forming agents and transitional colloids^[5]. TSP is use as binder in pharmaceutical tablet preparation. It has been also use as stabilizing agent, thickening, and gelling agent in food industry.^[6]

 

Recent ongoing research on tamarind gum is on the field of non toxic, biodegradable as well as biocompatible polymeric substance in the manufacturing procedure of oral controlled release dosage form. Tamarind gum has a huge scope open in the pharmaceutical industries due to its versatile characteristics and it is act as a pH sensitive polymer which also helps in targeted drug delivery system in tablet dosage form, ocular drug delivery system and in sustained release drug delivery systems.^[7] The composition of tamarind kernel powder, the source of gum with protein, oil, crude fiber, carbohydrates, and ash. Chemically, tamarind powder is a highly branched carbohydrate polymer which is shown in Fig. 1.

 

            

 

 

MATERIALS AND METHOD:

Materials:

Tamarind is amongst most common and commercially important large evergreen tree that is grown abundantly in the dry tracks of Central and South Indian states, and also in other South East Asian countries. Ethyl alcohol is able to get from Akshar Exim Company PVT.LTD.

 

Isolation of gum from Tamarind seed:^[8,9]

The crushed seeds of Tamarindus indica were soaked in water for 24hrs, boiled for 1 hrs, and kept aside for 2 hrs for release of gum into water. The soaked seeds were taken and squeezed in a muslin bag to remove marc from the filtrate. Then, to the filtrate, equal quantity of absolute ethyl alcohol was added to precipitate the gum. The gum was separated by filtration. The marc was not discarded but it was sent for multiple extractions with decreasing quantity of extracting solvent, i.e. water with the increase of number of extraction. The isolation was continued until the material was free of gum. The separated gum was continued until the material was free of gum. The separated gum was dried in hot air oven at temperature 40°C. The dried gum which is shown in Fig. 2 was powdered and stored in airtight containers at room temperature.

 

 

 

Evaluation:

Physicochemical characterization of tamarind gum:

Identification tests for carbohydrates:

As the authors were described in previous publication, Extracted gum was mixed with Molish’s reagent followed by addition of sulfuric acid. The violet color ring appeared at junction of mixture in test tube that confirms the presence of Carbohydrates.^[10,11]

 

Identification tests for proteins, mucilage and gums:

Aqueous solution of extracted gum was used for chemical characterization. Test for  proteins, mucilage, alkaloids, fats, tannins, amino acids and gums were perform according to standard procedure.^[10,11]

 

Organoleptic evaluation of isolated gum:

The isolated gum was characterized for organoleptic properties such as color, odor, taste, fracture and texture.

 

Solubility behavior gum:

It is  insoluble  in  organic  solvents like ethanol,  methanol,  acetone,  ether  and also in cold  water,  but  it  yields  a  highly viscous colloidal solution or a viscous gel at temperatures  above  85°C  is  completely  dissolved  in  hot  water.^[12]

 

pH of gum:

The extracted gum was weighed and dissolved in water separately to get a 1% w/v solution. The pH of solution was determined using digital pH meter.^[13]

 

Swelling index:

The swelling index is the volume (in ml) taken up by the swelling of 1 g of test material under specified conditions. The swelling index of the tamarind seed polysaccharides was determined by accurately weighing 1 g of tamarind seed polysaccharides, which was further introduced into a 25 ml glass-Stoppard measuring cylinder. 25 ml of water was added and mixture was shaken thoroughly every 10 min for 1 h. It was then allowed to stand for 3h at room temperature. Then the volume occupied by gum, was measured. The same procedure was repeated thrice and the mean value was calculated.^[12,14]

 

Bulk density and bulkiness:

The inverse of bulk density is called as bulkiness. Accurately weighed quantity of (50 g) was introduced into a graduated measuring cylinder. The cylinder was fixed on the bulk density apparatus and the volume occupied by the powder was noted. Then, the powder was subjected to tapping in a bulk density apparatus until constant volume was obtained. The final volume (bulk volume) was noted.^[15,16]

Bulk density is defined as:

Bulk density =

Weight of the powder / Bulk volume of powder

 

True Density:

Among various methods available for the determination of true density, liquid displacement method is the simplest method and was used in the present study. Acetone was selected as the liquid for displacement, because, tamarind polysaccharide is insoluble and heavy in acetone. This method has been used by authors.^{[ 11,15]}

 

Powder flow property:

The flow characteristics were measured by angle of repose. The experiment was repeated thrice. Using the readings and the formula, the angle of repose was calculated.

The formula used to measured the angle of repose is

tanØ =h/r                            

Where, h = Height of the heap

Ø =tan^-1 h/r                                      

r = Radius of the heap  

Lower the angle of repose, better the flow

properties.^{[ 11,15]}

 

 

Powder compressibility:

This property is also known as compressibility. The finely powdered gum (5 g) was transferred into a measuring cylinder and calculations were done using bulk density apparatus.^{[ 11,15]}

 

FTIR Study of tamarind gum:

IR spectra were recorded using an FTIR spectrophotometer by the KBR pellet method in the wavelength region between 4000-400cm^-1. The spectra obtained for Tamarind gum to check compatibility of the polymer with other polymers (Pectin, Locust Bean Gum).

 

DSC Study of tamarind gum:

The DSC thermo gram was recorded for Tamarind gum to check the melting point of the gum.

 

Result and discussion:

After extraction of the gum and then further precipitation by the ethyl alcohol the yield of tamarind gum was obtained 18.39% w/w. isolated gum was then used for identification test. This showed the presence of carbohydrates in the sample powder of the gum. The confirmatory test of gum was done when it gave negative test for mucilage, tannins, alkaloids and proteins given in Table 1.

 

Table 1: Chemical charactersitcs of isolated gum. Tests Present / Absent

Carbohydrate	+
Hexose Sugar	+
Monosaccharides	--
Proteins	--
Fats and oils	--
Tannins	--
Alkaloides	--
Amino acids	--
Mucillage	+

+ Present; -- Absent

 

This can be considered as a proof for purity of the isolated gum as depicted in organoleptic properties of gum was found to be accepted. Gum was odorless having the characteristics taste. Gum was light brownish in color with rough texture and rough fracture.

 

FTIR Study of tamarind gum:

IR spectra were recorded using an FTIR spectrophotometer by the KBR pellet method in the wavelength region between 4000-400cm^-1 which is shown in Fig. 3. The spectra obtained for Tamarind gum to check compatibility of the polymer with other polymers (Pectin, Locust Bean Gum).

                                

 

Differential Scanning Calorimetry Thermogram

The DSC thermogram analysis of tamarind gum shows the melting point of the gum as shown in Fig 4.

                            

 

 

After extraction of tamarind gum, organoleptic properties of gum were found to be accepted. Angle of repose is less than 30 that indicates powder is free flowing When Carr’s index values up to 15% generally show good to excellent flow properties of a powder which indicate desirable packing characteristics. The swelling property of extracted tamarind seed polysaccharide describe the high swelling ability which retard drug release up to desired time period. So it can be used in gel formulations for controlled drug delivery. Result in table 1 predicts that tamarind seed polysaccharide has appropriate physiochemical properties that can be used as pharmaceutical excipients.

 

 

 

 

 

Table 2: Physiochemical properties of Extracted Gum

 

CONCLUSION:

It was found that polysaccharide can be successfully extracted from tamarind seed using water based extraction procedure. It can be concluded from the whole study that tamarind seed derived polysaccharide can be used as a Pharmaceutical excipient for oral drug delivery system. It has pH value of 6, so nonirritant in nature. It was also predicted from the study that extracted polysaccharide can be used as a gelling agent in different pharmaceutical preparations.

 

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Received on 05.01.2018       Modified on 10.03.2018

Accepted on 21.04.2018       ©A&V Publications All right reserved