Screening, Development and Optimization of a Potential Herbal Film Forming Agent

 

Ayan Kumar Kar^*1, Rana Mazumder¹, Amitava Ghosh², Amitava Roy² and Surajit Saha²

¹Department of Pharmaceutics, Calcutta Institute of Pharmaceutical Technology and Allied Health Sciences, Howrah-711316, West Bengal, India.       ²Department of Pharmaceutics, Himalayan Pharmacy Institute, Majhitar, Rangpo, East Sikkim-737136.

*Corresponding Author E-mail: ayanonline008@gmail.com, rm_dreamsin@indiatimes.com

ABSTRACT:

The film of miracle herbal polymer, Moringa Oleifera was prepared along with 30% and 50% of plasticizers like propylene glycol, PEG-4000 and glycerol to ensure the spreading and/or the film forming capability of the herbal polymer. In this study, three plasticizers, namely polyethylene glycol 4000, propylene glycol and glycerol were selected and the aqueous film coating solution was prepared by incorporating different concentrations of the plasticizers. The evaluatory parameters of the prepared cast film of Moringa Oleifera like thickness, folding endurance, tensile strength, moisture loss, water uptake and vapour-pressure transmission rate were evaluated and the folding endurance value of the prepared films (F2, F6) was found satisfactory which ensures that the films prepared using the herbal polymer Moringa oleifera were having optimum flexibility and were no brittle. The percent moisture content (% W/W) of the film prepared with different proportion of glycerol and polyethylene glycol-4000 were found to be in between 3.2 to 3.5 (% W/W). It was observed that with increase in hydrophilic polymer concentration, the moisture content was also increasing. The water uptake (% W/W) of the film of the herbal polymer, Moringa Oleifera were found in between 4.1 to 4.4 (% W/W). In water uptake study, it was observed that the water uptake value increases with gradual increase in concentration of hydrophilic polymer. The water-vapour transmission rate through different film formulations showed that the films were permeable to water and the films showed uniform flatness without any observed constriction.

 

 

INTRODUCTION:

Natural gum of the miracle tree, Moringa oleifera was evaluated for its use in film preparation for the application as drug delivery systems and coating agents. This rapidly-growing tree also known as the horseradish tree, drumstick tree, benzolive tree, kelor, marango, mlonge, moonga, mulangay, nébéday, saijhan, sajna or Ben oil tree¹. It is a polyuronide consisting of arabinose, galactose, and glucoronic acid in the proportion of 10:7:2 moles². There are several reports about the successful use of that natural gums in various pharmaceutical preparations and also used as dental caries, astringent etc. Gum mixed with sesame oil is used to relieve headaches, fever, complaints, asthma and sometimes used to treat syphilis and rheumatism.

 

This tree has in recent times been advocated as an outstanding indigenous source of highly digestible protein, ca, Fe, Vitamin C, and carotenoids suitable for utilization in many of the so-called “developing” regions of the world where undernourishment is a major concern^{1, 3}. That gums were collected from the stem bark of the tree. The gum is initially white in color but changes to reddish brown to brownish black on exposure. It is sparingly soluble in water but swells in contact with water, giving a highly viscous solution^{1, 4}.

 

The cast film of the herbal polymer, Moringa oleifera was prepared along with different proportion of plasticizers like propylene glycol, PEG-4000 and glycerol to ensure the spreading and/or the film forming capability of the herbal polymer. The type and concentration of the plasticizers can affect the film properties, as revealed by several investigations. The proposed work is to screen some selected plant reported for its gum, exudates, and adhesive yielding properties. The extracts will be employed for treatments as herbal polymers, which will be used as a film-forming agent for the purpose of film coating a model drug candidate to retard its release.  Optimization of a polymer or a co-polymer blend, plasticizer, surfactants (if required) will also be deal practically for the development of the coating formulation.

MATERIALS AND METHODS:

Materials:

The Moringa oleifera exudates were collected from the local areas of the Himalayan region and PEG- 4000, Propylene Glycol , Glycerine were purchased form S.D Fines Chemical, Mumbai. All other chemicals were used as analytical grade.

 

Methods:

Preparation of Moringa oleifera Extract:⁵

Collection of the exudates:

The fresh exudates were collected from the fully-grown Moringa oleifera trees growing local areas of the Himalayan region. The bark of the trees were scrapped off and left undisturbed for 7-10 days. The scrapped portions were covered with a cotton membrane to prevent exposure to direct sunlight. The exudates in the form of the hard lumps were collected by using a hard knife after 10^th days.

 

Preparation of the Moringa oleifera powder (polymer):

Purified water was found to be the best solubility’s medium for Moringa oleifera. This was done by addition of the powder extracts with water on a glass beaker and was heated up to 60-70⁰C with continuous stirring. Once the powder gets dissolved within the aqueous phase, the whole content was poured on a Maslin cloth for filtration and the filtrate was collected in another glass beaker. The filtrate was mixed with an antioxidant, ascorbic acid to prevent any further oxidative damages and an edible preservative, methyl paraben to prevent the further microbial degradation. The filtrate was sprayed on a previously clean tray dries and subjected to dry on an hot air oven(lab instruments, siliguri) at 40⁰±2⁰C, After 2 days of drying the flakes obtained at the bottom were collected and was crushed in the mill(Shakti engineering, India). The powders were collected and were stored in a completely air-tight zipper pack for further use.

 

Preparation of the film:^{6, 7}

The coating solution of the gum was prepared by dispersing the gum in distilled water; it was allowed to equilibrate for a period of 24 h. The gum solution was mixed with different plasticizers: glycerin, propylene glycol, polyethylene glycol (PEG 400) in the proportions 50% and 30%.  With gentle stirring for a period of 10 min. The mixtures prepared were poured in the Petri dish, for casting the films. They were allowed to dry in a closed chamber to control the evaporation for 24 h at 40⁰c temperature. After 24 hours, the films were observed for drying and appearance.

 

Film thickness measurement:^{6- 8}

Five coated tablets were randomly selected from each batch and the thickness was measured individually using a slide callipers. The difference in the thickness with respect to uncoated tablet gave the coat thickness. The cast film thickness measurement was done by peeling off the adhering films from the substrate surface. Uniformity in thickness was measured by selecting four different zones of the cast films. The average of each formulation is noted.

Water Uptake determination:⁶

The water uptake was determined by drying the films at 60°C with a current of air, after which the films were subjected to desiccation over calcium chloride at 40°C for 24 h. These samples were weighed and exposed to 70% relative humidity at room temperature. This relative humidity was achieved using saturated solutions of sodium chloride. After equilibration under this humidity, films were weighed for determining the increase in weight and % water uptake was calculated.

 

Vapour-pressure transmission rate determination:⁷

For this study, glass vials were used as the transmission cells. These cells were washing thoroughly and dried in a woven. The coating film of known thickness was fixed over the edge of the glass vials containing 3gm of fused calcium chloride as a desiccant. Then the transmission cells were weighed accurately and initial weight was recorded. The cells were then kept in a desiccators containing saturated solution of potassium chloride (200 ml). The humidity inside the desiccators was to be 80-90% RH. The cells were taken out periodically and weighed for a period of72hours. The experiment was performed and values were calculated by using the formula of

                              WVT rate = WL/S

Where, W = Water vapour transmitted in gm.

L = Thickness of the film.

S = Exposed surface area in cm².

 

Tensile strength determination:⁶

In order to determine the elongation for calculating tensile strength, the polymeric film was pulled by means of a pulley system; weights were gradually added to the pan to increase the pulling force till the patch was broken. The elongation, i.e., the distance travelled by the pointer before breaking of the patch was noted on a graph paper with the help of magnifying glass, and the tensile strength was calculated as g/cm².

 

RESULTS AND DISCUSSION:

The Moringa film prepared by the different plasticizers which is described by the table no-1 and the evaluation parameters of the prepared cast film of Moringa oleifera like thickness, folding endurance, tensile strength, Moisture loss, water uptake and vapour-pressure transmission rate were described by table no-2. The folding endurance value of the prepared films (F2, F6) was found satisfactory which ensures that the films prepared using the herbal polymer Moringa oleifera were having optimum flexibility and were no brittle. The percent moisture content (% W/W) of the film prepared with different proportion of glycerol and polyethylene glycol-4000 were found to be in between 3.2 to 3.5 (% W/W). It was observed that with increase in hydrophilic polymer concentration, the moisture content was also increasing. The water uptake (% W/W) of the film of the herbal polymer, Moringa oleifera were found in between 4.1 to 4.4 (% W/W). In water uptake study, it was observed that the water uptake value increases with gradual increase in concentration of hydrophilic polymer.

 

Table No.1 Observation of the Moringa film prepared by the different plasticizers.

Formulation (Ingredients in ml)	F1	F2	F3	F4	F5	F6
Moringa oleifera	6	6	6	6	6	6
PEG 4000	1.8	3	-----	-----	----	----
Propylene Glycol	----	------	1.8	3	----	----
Glycerol	----	------	----	-----	1.8	3
Observation after drying (24 hours)	Wet	Satisfactory	Wet	Dried	Wet	Satisfactory

 

Table No.2 Evaluation parameter of the Moringa oleifera film.

Formulation	Thickness (mm)	Folding endurance	Tensile strength (g/cm2)	Moisture Loss (% W/W)	Water Uptake (% W/W)	Vapour pressure transmission rate (gm/dm2)
F7B	0.4	173±10	1.09	3.546	4.331	2.55
F7F	0.3	144±08	1.01	3.282	4.109	2.212

Values expressed in mean± Standard Deviation (n=3)

 

The water-vapour transmission rate through different film formulations showed that the films were permeable to water and the films showed uniform flatness without any observed constriction. The tensile strength of the films was found in between 3.2 to 3.6 gm/cm². It was found that with changes in concentration of plasticizers, Moringa oleifera, the tensile strength of the films changes gradually. Comparative analysis of different properties of prepared film was shown in fig. no-1 and the photocopy of the Moringa oleifera film was shown in fig. no-2.

Fig. No.1 (1A, 1B, 1C, 1D) Comparative parameters of prepared films of Moringa oleifera.

 

Fig. No.2 Film of Moringa oleifera.

 

CONCLUSION:

It can conclude that the gum has enormous potential for use in the preparation of the polymeric films as the drug delivery systems. It can also be used as a water-impervious coating agent in tablets, as it has a low vapor-pressure rate and a satisfactory tensile strength and also it can be used as a coloring agent in the coating solution. And also stated that plasticizers like PEG-4000 and glycerol at 50% have a significant effect on the film forming property of the natural gum Moringa oleifera. The films formed with different proportion of Moringa oleifera were free from major defects like good gloss and very slight sticking property as it is a natural gum. From the last study, it indicated that plasticizers significantly influence the quality of the aqueous film coat.

 

The Moringa oleifera with the addition of glycerin at 50% could be considered as an elegant film forming formulation for solving different coating problems generally faced in an industrial scale.

 

REFERENCES:

1.       Vidya S, Patel V, and Paranjape A, Sakarkar SN, and Sabale PM. Moringa Oleifera: an overview. Phcog Rev. 2008; 2(4): 7-13.

2.       www.TFLJournal.org

3.       www.wickipedia.com

4.       Dishna S. Water clarification using Moringa Oleifera. Gate Technical Information 2000; 1-7.

5.       Ravindra VK, Navneet BG, Alagawadi R and Rudraprabhu VS. Effect of Moringa Oleifera Lam. Root-wood on ethylene glycol induced urolithiasis in Rats. J Pharmacol. 2006; 105: 306-311.

6.       Panda DS, Choudhury NSK and Gupta R. Evaluation of film forming potential of a natural gum. Asian J Pharmaceut. 2008; 2: 49-54

7.       Bondmeier R, Paeratakul O. Evaluation of drug containing polymer films prepared from aqueous latexes. Pharm Res. 1989; 6:725-730.

8.       Aulton MH and Abdul R. The mechanical properties of hydroxy propyl methylcellulose films derived from aqueous systems. Drug Dev Ind Pharm. 1984; 6(2): 649-668.            

 

 

Received on 20.10.2009       Modified on 23.12.2009

Accepted on 12.01.2010      © RJPT All right reserved