Formulation And Evaluation Of The Tablets Prepared With Chloroform Extract Of Pandanus Fascicularis Lamk. Leaves

Prabhudutta Panda^*,Maitrayee Panda, Siva Shankar Nayak and Durga Prasad Panda

College of Pharmaceutical Sciences, Mohuda, Berhampur-760002, Orissa, India

ABSTRACT

The pharmacological evaluation of the chloroform extract of Pandanus fascicularis Lamk. leaves was found that it is having antinociceptive and anti-inflammatory properties, and contains the phytoconstituents viz., steroids, terpenoids, flavonoids, saponins and tannins. Therefore tablets were formulated with the extract by wet granulation method. The mechanical properties of the tablets like crushing strength and friability were assessed. The drug release properties were evaluated by using in-vitro disintegration and dissolution methods. There were statistically significant differences (p<0.01) in the crossing strength friability ratio (CSFR) of the tablets. The differences in drug release depend on the types and concentration of the excipients and the binders employed in the formulation. PVP, gelatin and corn starch were used in different concentrations i.e. 1% w/w and 4% w/w with purified water as binder solutions, for the preparation of tablets. The ranking of crushing strength values for tablets was PVP > gelatin > corn starch. The CSFR values also increased with increasing compression force and concentration of binders employed. The ranking of CSFR values for tablets was PVP > gelatin > corn starch. The dissolution time and t₈₀ (time required for 80% release of the extract) were studied with Double beam UV-VIS Spectrophotometer at 271 nm. The ranking of disintegration and dissolution times exhibited by tablets was PVP >gelatin > cornstarch. There was no change in mechanical and drug release properties of the tablets after storage at temperature of 30±2 ⁰C and relative humidity of 75±5% for twelve months.

Keywords: Pandanus fascicularis Lamk. leaves, chloroform extract, tablets, in- vitro evaluation

INTRODUCTION

Pandanus fascicularis Lamk. (Family-Pandanaceae) is a dioecious shrub, densely branched with copious aerial roots are found in the coastal region of India ¹. This plant is well known under vernaculars as ‘Fragrant screw pine’ in English, ‘Kia’ in Oriya, and ‘Ketki’ in Hindi and ‘Dhuli puspika’ in Sanskrit ^2,3,4. The leaves of P. fascicularis Lamk. are used in traditional medicine to treat tumors, leprosy, smallpox, scabies, leucoderma and blood diseases. Juice obtained from inflorescence from which the spathes have been removed used for rheumatic arthritis in veterinary medicine ^2,3,4,5. This plant contains main chemical constituents viz; cirsilineol, n–triacontanol, physcion, compesterol, daucosterol, β-sitosterol, β-sitostenone, stigmasterol and stigmust-4-en-3, 6-dione ^4,6. The literature reveals that the P. fascicularis Lamk. leaves are used orally against pain, inflammation and epilepsy in traditional system and pharmacologically, this plant extract has been proved for its antinociceptive and anti-inflammatory activities in animal models⁷. In spite of their efficacy, herbal medicinal products have been widely criticized due to lack of standardization and poor-quality presentation. However, to improve patient compliance and acceptance, there is need to formulate the leaves of P. fascicularis Lamk. into tablet dosage form ⁸.

Table-1: Evaluations of the tablet prepared from different concentrations of excipients and extracts using different pharmaceutical parameters

Binder (%w/w)		Drug (%)	Crushing Strength (N)	Friability (%)	CSFR	DT (min)	t80 (min)
PVP	1%	97.86±0.54	103.06±1.25	0.63±0.03	164.44	8.34±0.06	78.82±0.18
		98.42±0.62	110.91±1.19	0.61±0.02	181.81	8.80±0.04	80.75±0.26
	4%	98.54±0.36	163.89±1.13	0.53±0.01	309.22	17.82±0.03	157.73±0.26
		97.82±0.48	179.55±0.71	0.43±0.02	417.55	18.19±0.04	163.21±0.28
Gelatin	1%	98.38±0.42	96.18±0.53	0.68±0.03	141.44	10.36±0.05	86.92±0.32
		98.68±0.52	122.68±0.57	0.55±0.03	223.05	10.68±0.04	88.68±0.46
	4%	97.14±0.64	118.77±0.65	0.58±0.02	204.77	12.25±0.03	110.25±0.18
		97.24±0.56	174.68±0.61	0.55±0.04	317.6	14.17±0.04	114.26±0.21
Corn Starch	1%	98.36±0.44	40.28±0.52	0.56±0.03	71.92	4.26±0.03	30.54±0.28
		97.68±0.38	49.11±0.69	0.75±0.02	65.48	4.82±0.06	34.33±0.18
	4%	97.82±0.64	83.44±0.53	0.64±0.03	130.37	5.22±0.03	38.89±0.24
		98.22±0.48	116.81±0.61	0.52±0.02	224.63	5.64±0.04	42.72±0.17

Table 2: Model fitting analysis of Tablet Drug release of optimum formulation

Tablet	Zero order	First order	Higuchi	Peppas	“n”	Mechanism
Starch 1,5 N	R^2= 0.9478	R^2= 0.952	R^2= 0.9776	R^2= 0.9344	1.168	Supre case II transport
Starch 1,10 N	R^2= 0.9713	R^2= 0.9401	R^2= 0.964	R^2= 0.9544	1.1835	Supre case II transport
Starch 4,5 N	R^2= 0.9389	R^2= 0.9789	R^2= 0.9762	R^2= 0.9469	1.09	Supre case II transport
Starch 4,10 N	R^2= 0.9533	R^2= 0.9688	R^2= 0.9744	R^2= 0.9524	1.085	Supre case II transport

Thus, the aim of the present study is to produce conventional tablets from the extracts of the leaves of P. fascicularis Lamk. for oral administration prepared by using wet granulation method. The mechanical properties of the tablets were assessed using crushing strength and friability while the drug release properties were assessed using the disintegration and dissolution times.

MATERIALS AND METHODS:

Plant material:

Pandanus fascicularis Lamk leaves were collected during the month of August from the rural belt of Arjipoli in Ganjam District, Orissa, India, identified and authenticated by Prof. S. K. Dash, Head, PG Department of Bioscience, College of Pharmaceutical Sciences, Mohuda. The collected plants were washed and air-dried under the shade, cut into small pieces, powdered by a mechanical grinder and passed through 40-mesh sieve and stored in a closed vessel for future use.

Preparation of Extract:

The dried, powdered leaves of P. fascicularis Lamk. (1kg) were extracted successively with 1200 ml of petroleum ether (60–80⁰C) and 1200ml of chloroform in soxhlet apparatus. A dark greenish black coloured petroleum ether extract was obtained. The same powdered leaves (marc), after proper drying, were extracted with chloroform (18 h) to produce a greenish brown semisolid mass. The extractions were carried out until the solvents became colorless. These extracts were again dried and concentrated by evaporating the solvent completely under vacuum at the range of boiling points of solvent (Chloroform at 62 ⁰C) using rotatory evaporator (Jain Scientific glass works, DTC 201, Ambala cantt, India) The chloroform extract (yield 21.6% w/w with respected to dry powdered plant material) was selected for all experimental procedure. The chemical constituents of the extract was identified by qualitative analysis and confirmed by the thin layer chromatography (i.e. hR_f values).

Chemicals used:

Corn starch, Magnesium stearate, Gelatin, Lactose (purchased from Himedia Laboratories Pvt. Ltd, Mumbai). Polyvinyl pyrrolidone, petroleum ether, chloroform (purchased from Loba Chemie Pvt. Ltd, Mumbai).

Preliminary phytochemical analysis:

The chloroform extract of P. fascicularis Lamk. leaves was subjected to preliminary phytochemical screening for detection of major chemical groups. In each case test 10% w/v solution of the extract in chloroform was used and unless otherwise mentioned in individual test ⁹. Results of different chemical tests on the chloroform extract of P. fascicularis Lamk. showed the presence of phytoconstituents viz., steroids, terpenoids, flavonoids, saponins and tannins.

Determination of maximum absorption of P. fascicularis Lamk. leaves extract:

To determine the maximum absorption, 100 mg of extract was placed in 1000 ml flask and 1L of chloroform was added. The flask was agitated to get a concentration of 100 µg/ml. The absorption spectrum of the solution of the extract was recorded using a UV spectrophotometer (Model: SL-159-Shimadzu-1700, SI-164 Double Beam) and the wavelength for maximum absorption was determined. Various concentrations of the chloroform extract of P. fascicularis Lamk. leaves were prepared to contain between 0.01to 0.1mg/ml of extract in chloroform. The absorbance of each concentration was taken at 271 nm and plotted against the various concentrations to obtain the calibration curve for the extract.

Preparation of Granules:

Batches (200g) of a basic formula Pandanus fascicularis Lamk. extract (20%w/w), lactose (70%) and Corn starch (10%) were dry mixed for five minutes in a planetary mixer (Remi Instruments, Mumbai, India) and then moistened with (1% w/w or 4% w/w) concentration of binder solution with (PVP, corn starch and gelatin mucilage). The wet masses were granulated by passing them manually through a No. 12 mesh sieve (1,400 µm) (Geologist’s Syndicates. Pvt. Limited. Calcutta, India), dried in hot air oven for 18 hours at 50 ⁰C, and then resieved through a No. 16 mesh size (1000 µm). The granule were stored in airtight containers. The moisture contents of the powder and granule formulations were determined with (Infra red Moisture Balance, Macro Scientific works, Delhi, India) and found to be between 1.2 and 1.4% w/w.

Figure1: The release profile of P. fascicularis tablet with Starch as binder (mean± SD, n = 3)

Preparation of Tablets:

Tablets (final weight–500mg) were prepared from the powder mixture and granules (500-1000 µm size fraction) by compressing the materials for thirty seconds with predetermined load of 5 and 10 KN using a ( Kimaya Pellet press Bearing, KP–703, Thane, Moharashtra, India). Before each compression, the dia (10.5 mm diameter) and the flate-faced punches were lubricated with a 2 %w/w dispersion of magnesium stearate in ethanol: ether (1:1 solution). After ejection, the tablets were stored over silica gel for 24 hours to allow hardening and elastic recovery.

Crushing Strength and Friability Test:

To determine the crushing strength and the friability test, the load (N) required to diametrically breaking each tablet (crushing strength) was determined at room temperature using (digital model EH 01, Electrolab, Mumbai, India). The friability of the tablets were determined using a friabilator (Model TF 2D, Scientific Equipment Ltd., Bombay, India) operated at 25 revolutions per minute for 4minute ^10-13.

Friability Test:

It is usually measured by the use of the Roche friabilator. Ten tablets are weighed and placed in the apparatus where they are exposed to rolling and repeated shocks as they fall 6 inches in each turn within the apparatus. After four minutes of this treatment or 100 revolutions, the tablets are weighed and the weight compared with the initial weight^10,11.

Disintegration Test:

The disintegration test is carried out using the disintegration tester (double basket, C-TD2, Campbell Electronics, Mumbai, India) which consists of a basket rack holding 6 plastic tubes, open at the top and bottom, the bottom of the tube is covered by a 10-mesh screen. The basket is immersed in water at 37 ^oC, in a 1L beaker ¹⁴.

Dissolution Test:

To investigate the dissolution test, the dissolution times of the tablets were determined at 37±0.5 ⁰C in 900 ml of 0.1M HCL using a Dissolution Test Apparatus (MDR-D6, Tab machine, Mumbai, India) with the basket rotated at 50 rpm. 5ml samples were withdrawn and replaced with fresh medium at fixed time intervals. The samples were diluted and the amount of drug released was determined spectrophotometrically at 271 nm. Each of the results is the mean of four determination. The results were extrapolated in (Table-1).

Content Uniformity Test:

To determine the content uniformity, ten tablets were crushed from each batch and. each tablet was dissolved in 10 ml of chloroform and then filtered through a Whatman filter paper. The solution was further diluted with chloroform and the absorbance of each concentration was taken at 271 nm ¹⁰. The amount of drug present in each tablet was calculated by using calibration curve. Results given in (Table-1) are the average of triplicate values. Content uniformity is express as Mean ±Standard deviation.

Stability studies:

To investigate the stability studies, the tablets were stored at a temperature of 30±2 ⁰C and relative humidity of 75±5 % for a period of twelve (12) months. The mechanical and release properties of the tablets after storage were assessed ¹⁵.

Statistical analysis:

The experimental results were expressed as the Mean ± Standard error of mean (SEM) and the statistical significance was evaluated by One-way analysis of variance (ANOVA) followed by Dunnett’s t-test ¹⁶.

Kinetic analysis of dissolution data:

Kinetic models have described drug dissolution from solid dosage forms where the dissolution amount of drug is a function of the test time ¹⁷. The drug profile was subjected to different models of drug release (Zero order, First order, Higuchi model and Korsmeyer – Peppas model) and best-fit model was selected on the basis of Correlation coefficient (R²) and the values “n” is determined for Korsmeyer – Peppas model. The “n” value in Korsmeyer – Peppas model is used to indicate different release mechanism. When the value of n = 0.5 indicate Fickian diffusion-controlled drug release, when it in between 0.5 to 1 indicate Anomalous transport, n = 1 show Case II transport and n > 1 indicate Super case II transport ^17,18. This is shown in Table 2.

Optimization of formulations:

From the stability studies, all the formulation of tablet showed no changes in Drug content, crussing strength, friability, dissolution and disintigeation at the end of the experiments. The dissolution and disintigeation of tablet prepared by using corn starch (as binder) take less time as compared other tablets. Hence, the tablet prepared by starch as a binder was optimized.

RESULTS:

The results of the Pandanus fascicularis Lamk. leaves tablets prepared using wet granulation is shown in Table 1. The results indicate that Crussing Strength increased while Friability decreased with increase in the compression force. The ranking of crushing strength values for tablets was PVP > gelatin > corn starch. The CSFR values also increased with increasing compression force and concentration of diluent/binder employed. The ranking of CSFR values for tablets was PVP > gelatin > corn starch. The drug release properties of pharmaceutical tablets are characterized by the disintegration and dissolution times. The result of the spectrophotometric analysis shows that the chloroform extracts of Pandanus fascicularis Lamk. leaves exhibited a principal absorption maximum at 271nm. Thus, the calibration curve to assess the release properties of the tablets were determined at a wavelength of 271nm and the linear regression equation for the plot of absorbance versus concentration was given as Y = 0.004x+0.001 with coefficient of determination, R² = 0.999. The amount of drug released was plotted against time and representative plots for tablets containing the extract alone. The dissolution time and t₈₀ (time required for 80% of Pandanus fascicularis Lamk. to be released respectively) were obtained from the dissolution profiles of the tablets. The ranking of disintegration and dissolution times exhibited by tablets was PVP >gelatin > cornstarch. There was no change in mechanical and drug release properties of the tablets after storage at temperature of 30±2 ⁰C and relative humidity of 75±5% for twelve months.

DISCUSSION:

The mechanical properties of pharmaceutical tablets are important tests for pharmaceutical tablets that often form part of a manufacturer’s own specification which are quantifiable by the crushing strength (CS) and the friability (F) of the tablets. The CS provides a measure of tablet strength while F is a measure of tablet weakness ^19,20. Both parameters indicate the ability of tablets to withstand fracture and abrasion during production and subsequent use ^19,21. The Pharmacopoeial requirements ¹⁹ for the crushing strength is largely dependent on the intended use of the tablet, while for friability, conventional compressed tablets that lose less than 1% w/w of their mass during the friability test are generally considered acceptable ^19,20,22. Tablets prepared by wet granulation using all the binders on the other hand, showed acceptable CS and F values at the concentrations employed, indicating the suitability of wet granulation method for the production of Pandanus fascicularis Lamk. leaves tablets. Furthermore, there were statistically significant (p<0.01) differences in the CSFR values of Pandanus fascicularis Lamk. leaves tablets. All formulations of Pandanus fascicularis Lamk.leaves tablets complied with the official requirement on disintegration (i.e. disintegration within 15 minutes). The dissolution times of the tablets also varied and depended on the type and concentration of the binding agent employed. Tablet prepared by wet granulation did not meet the official requirement on dissolution for uncoated tablets (i.e release of 75% w/w of the active drug within 45min) ¹⁹ except for tablets prepared using corn starch as binding agent. The results indicate the importance of the inclusion of excipients such as disintegrant in the formulation of tablets. Generally no statistically significant (p >0.05) differences between the mechanical properties of tablets after storage at 30±2 ⁰C and 75±5 % relative humidity for twelve months. There

were also no significant differences in the disintegration and dissolution times of the tablets after the period of storage. The results indicate that the tablets were generally stable under tropical storage conditions. The tablets containing corn starch as binding agent, used in wet granulation, fulfilled the pharmacopoeial requirements on mechanical and drug release properties. Thus, the methods of preparation of the Pandanus fascicularis Lamk. leaves tablets need to be carefully selected to ensure the production of tablets with adequate bond strength to withstand the rigors of handling and at the same time release the active compound (s) for biological action. Furthermore, the type and concentration of excipient and binder employed in the formulation of Pandanus fascicularis Lamk. leaves tablets need to be carefully chosen to enable the production of suitable tablets.

ACKNOWLEDGEMENT:

Authors are thankful to the authority of the College of Pharmaceutical sciences, Mohuda, Berhampur, India for laboratory facilities and also thankful to the Prof. S. K. Dash, Head, PG Department of Biosciences, College of Pharmaceutical sciences, Mohuda, Berhampur, for the identification of the plant.

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Received on 13.05.2009

Accepted on 10.06.2009

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Research Journal of Pharmacognosy and Phytochemistry. 1(1): July.-Aug. 2009, 54-58