INTRODUCTION:

Excipients are the additives used to convert active pharmaceutical ingredients into pharmaceutical dosage form suitable for administration to patients.¹ New and improved excipients continue to be developed to meet the needs of conventional drug delivery systems and to meet the needs of advanced tablet manufacturing.

A number of researchers have explored the utility of plant based materials as pharmaceutical excipients.^{2, 3} Majority of investigations on natural polymers in drug delivery systems are centered on polysaccharides and proteins, due to their ability to produce a wide range of materials and properties based on their molecular structures.⁴ Number of natural, semi synthetic and synthetic polymer materials are used in the various drug delivery systems. Natural polysaccharide gums represent a group of polymers which swell to form highly viscous solutions or dispersions in aqueous media. They have found wide application in pharmaceutical formulations such as polymer matrices in sustained release solid dosage forms,^5,6 binders in tablets,⁷ stabilizers or suspending agents in liquid dosage forms ⁸ and in bioadhesive drug delivery systems.⁹

Plant products serve as an alternative to synthetic products because of local accessibility, environment friendly nature and lower prices compared to imported synthetic products.

The Pisum sativum seed powder were selected from natural sources as binder due to its distinguished characters such as low cost, abundant availability, ease of isolation, stickiness, viscosity, good flavor, nutritional value and taste masking nature. Pisum sativum, commonly known as Green Peas/Garden Pea, plant of the leguminous family, available from spring through the beginning of winter. Peas have both low-growing and vining cultivars. The veining cultivars grow thin tendrils from leaves that coil around any available support and can climb to be 1–2 m high. In modern times peas are usually boiled or steamed, which breaks down the cell walls and makes the taste sweeter and the nutrients more bioavailable. Most investigations on impacts on health have been performed on green peas.¹⁰

Lornoxicam is 6-chloro-4-hydroxy-2-methyl- N-2-pyridinyl-2H-thieno-[2, 3-e]-1, 2- thiazine-3-carboxamide 1, 1-dioxide; is a novel non-steroidal anti-inflammatory drug, analgesic and antipyretic properties.¹¹ It belongs to the chemical class oxicams, which is commercially available in oral/ parenteral dosage form, is used to treat inflammatory diseases of the joints, osteoarthritis, pain after surgery, and sciatica. It works by blocking the action of cyclooxygenase, an enzyme involved in the production of chemicals, including some prostaglandins in the body.

The main objective of present research work was to investigate the binding efficacy of Pisum sativum seed powder in lornoxicam tablet formulations in comparison with standard binder such as acacia.

MATERIALS AND METHODS:

Pisum sativum dry fruit seeds are purchased from local market. Lornoxicam was gift sample from Macleod Pharmaceutical Ltd; (Mumbai India). Ruthenium Red purchased from Oxford laboratory, Mumbai. Micro crystalline cellulose (MCC), lactose, acacia, magnesium stearate and talc were supplied by SD Fine Chemicals (Chennai, India). All chemicals used in the study were of analytical grade.

Preparation of Pisum sativum:

The dehusked seeds of Pisum sativum was properly washed with distilled water and dried in a oven at temperature less than 50⁰C. The dried seeds were powdered in a ball mill and passed through # 120 sieve using sieve shaker and stored in desiccator until further use.

Characterization of Pisum sativum:

The Pisum sativum seed powders were characterized for phyto - physicochemical properties. The phyto-chemical examinations such as molisch test and iodine test confirm the presence of carbohydrates and polysaccharides respectively. The physicochemical properties such as loss on drying, pH and viscosity were determined according to Indian pharmacopoeial procedure.¹² The pH of 1% solution was measured using a digital pH meter by dispersing the seed powder in 25ml of distilled water. The viscosity of the seed powders (2% w/w) was determined using RVDV II+ viscometer (Brookfield Engineering India, Mumbai). Prior to the study, the sample was filled in the sample adapter and allowed to stand for 24h undisturbed for complete relaxation of the sample.¹³ Viscosity was determined using spindle S28, at 50 rpm using a constant temperature bath maintained at 20⁰C.

Preparation and evaluation of mixed blend of drug and excipients:

All the ingredients were passed through mesh no #80. Required quantity of each ingredient was taken for each specified formulation as shown in table 1 and all the ingredients were subjected to grinding to a required degree of fineness. The powder blends were evaluated for flow properties such as bulk density, tapped density, % porosity, Hausner ratio, Carr’s index, angle of repose, bulkiness.^14,15

The bulk density (b*) was determined by pouring the blend into a graduated cylinder. The bulk volume and weight of the powder was determined. The bulk density of the sample was calculated by weight of the powder/bulk volume. The measuring cylinder containing a known mass of blend was tapped mechanically, using a bulk density apparatus (Electrolab, Mumbai, India) until a constant volume was obtained, which was referred as tapped volume. The tapped density of the sample was calculated by weight of the powder / tapped volume. The percentage porosity was calculated by (bulk density-tapped density/bulk density) ×100. The Hausner ratio was determined by tapped density / bulk density. Carr’s index was calculated by tapped density - bulk density /tapped density) ×100. Angle of repose was determined using funnel method. The blend was poured through a funnel that can be raised vertically until a maximum cone height was obtained. Radius of the heap was measured and angle of repose was calculated by tan^-1(cone height/radius of the heap). Specific bulk volume or reciprocal of bulk density is called as bulkiness. The bulkiness was calculated by 1/bulk density.

Compression of tablets:

The different batches F1 to F8 (8g) of lornoxicam tablets were prepared using different concentration of Pisum sativum seed powder and acacia using the formula as shown in table 1. Here, acacia was used as the standard binder for comparison. All ingredients were triturated individually in a mortar and passed through #80 sieve. Then required quantity of all ingredients were weighed for a batch size of 100 tablets and mixed uniformly in a mortar. This uniformly mixed blend was compressed into tablets containing 8 mg drug using 6.2 mm flat face surface punches on a MT Rimek-12 rotary tablet machine by direct compression method. Total weight of tablet was kept 150 mg.

Table 1: Formulation of different batches of lornoxicam tablets using Pisum sativum seed powder and Acacia as binders

Ingredients (mg)	F1^a	F2^a	F3^a	F4^a	F5^b	F6^b	F7^b	F8^b
Lornoxicam	8	8	8	8	8	8	8	8
*Pisum sativum* seed powder	5	10	20	30	-	-	-	-
Acacia	-	-	-	-	5	10	20	30
Mcc^c	30	30	30	30	30	30	30	30
Lactose	103	98	88	78	103	98	88	78
Magnesium stearate	2	2	2	2	2	2	2	2
Talc	2	2	2	2	2	2	2	2
Total (mg)	150	150	150	150	150	150	150	150

^aFormulation batches F1, F2, F3, F4 contains Pisum sativum seed powder with 3.3%, 6.6%, 13.3%, 20% binder respectively

^bFormulation batches F5, F6, F7, F8 contains Acacia with 3.3%, 6.6%, 13.3%, 20% binder respectively

^CMCC indicates micro crystalline cellulose

Evaluation of the lornoxicam tablets

The prepared tablets were evaluated for thickness, volume of tablet, packing fraction, tensile strength, tablet physical stability, content uniformity, weight variation, hardness, friability, disintegration time and in-vitro dissolution studies. Tablet weight and dimensions were measured. The packing fraction (Pf) was calculated using weight of tablet/volume of tablet × the particle density of the lornoxicam (1.727g/cm³) used in the tablet formulation.¹⁶ The tensile strength (σ_t) of tablet which is a measure of the stress necessary to cause diametral fracture of the compact was determined from the mean data obtained from the hardness test carried out on the tablets (n = 10) using the Mosanto hardness tester. The σ_t values were computed from equation below¹⁷:

σ_t = 2P/πDt

Where, P is the load applied on the tablet that causes diametral fracture of the tablet of diameter, D and t is the tablet diameter and thickness (m).

Tablet physical stability of tablet was calculated by using hardness/disintegration × friability ratio.¹⁶ The hardness of the tablets was determined using a pfizer hardness tester (SCHNEUNIGER).The percentage of friability, disintegration, content uniformity and dissolution were performed by following the official method given in USP The percentage of friability of the tablets was determined using Roche tablet friabilator (Indian Equipment Corporation, Mumbai, India) operated at 25 rpm for 4 min. ¹⁸ Disintegration time was determined in distilled water at 37±1⁰ C using disintegration apparatus (ELECTROLAB - ED-2L, Mumbai, India).

The rate of dissolution of lornoxicam from the tablets was studied in a rotary paddle USP (XXIII) apparatus II (Electrolab, Mumbai, India) operated at 50 rpm. The dissolution medium was 900ml phosphate buffer at pH 7.8 at 37±0.5⁰ C. At specified time intervals, 5ml samples were withdrawn and immediately replaced with 5ml samples of fresh buffer solution maintained the sink conditions at the same temperature. The amount of lornoxicam in each sample was analyzed spectrophotometrically with UV-Double beam spectrophotometer (LABINDIA^® UV-3000, Chennai, India) at 376nm. All parameters were made in triplicate.

Statistical analysis:

Statistical analysis was done to compare the effects of Pisum sativum seed powder and acacia on the tablet binder properties using the two way ANOVA. At 95% confidence interval, the p value lower than or equal to 0.05 was considered the limit of significance.

Stability Studies

Stability studies were carried out as per ICH guidelines. The optimized tablets were packed in screw capped high density polyethylene containers and isothermally stressed to study the stability under accelerated temperature and relative humidity (RH) conditions (40 ⁰C and 75% RH) in stability chambers (Thermo lab, Mumbai, India) for 3 months. Test samples were withdrawn every month and subjected to various tests, including visual inspection for any appreciable change on the tablet surface, hardness, disintegration and in vitro drug release. Similarity factor values were calculated to verify the similarity of the dissolution profiles. FT-IR spectroscopy was used to characterize the stability of the formulations.

RESULTS AND DISCUSSION:

The seed powders were used as binder for developing lornoxicam oral uncoated solid dosage form. The seed powders were characterized for phyto-chemical examinations, pH, viscosity and loss on drying to assess the Pisum sativum seed powder as excipient (binder) for developing lornoxicam tablets. In molisch test pinkish red ring formed it indicates the presence of carbohydrates and in iodine test observed blue spots under microscopic study indicates the presence of polysaccharides. The pH of Pisum sativum seed powder solution (1% w/v) were 6.8 and 6.6, which indicates that the seed powder was suitable for solid oral dosage form. Viscosity of Pisum sativum seed powders was found to be 5.45 Ns/m². The powder blends were evaluated for bulk density, tapped density, % porosity, Hausner ratio, Carr’s index, angle of repose, bulkiness. The results for powder blends evaluations were shown in table 2. There was no significant difference in their bulk densities, tapped densities and porosity in all the prepared granules. All the formulations had a Carr’s index between 17.18 to 18.96% while their Hausner ratios were below 1.24 and angle of repose below 30⁰ indicates good flow properties.

The table 3 shows the properties of lornoxicam tablets in comparison to Pisum sativum seed powders and acacia at different binder concentrations. Volume of tablet results showed better consolidation of powder blend producing more cohesive tablet compact. Hardness/disintegration x friability ratio has been identified as better index of tablet quality than has traditional hardness-friability ratio. This index not only assesses the tablet strength (i.e. hardness) and weakness (i.e. friability), but it simultaneously evaluates any negative effects of these parameters on disintegration. The rank order effect of binders on tablet quality values was Pisum sativum seed powder seed powder>acacia. The content uniformity and weight variation of all batches F1 to F8 of tablets within the specified USP limits. The hardness of the prepared tablets was all within the acceptable range of 3 to 4 Kgs.

All the batches of Pisum sativum powder complied with the requirements of the Indian Pharmacopoeia which states that not more than one tablet weight should vary by more than 5% and none by more than 10% of the mean tablet weight. Weight loss in the friability test was less than 0.9 % in all the cases.

Table 2: Evaluation of mixed blend of drug and excipients

Parameters	*Pisum sativum* seed powder^a				Acacia^b
% Binder (Batch)	3.3% (F1)	6.6% (F2)	13.3% (F3)	20% (F4)	3.3% (F5)	6.6% (F6)	13.3% (F7)	20% (F8)
Bulk density (g/ml)	0.49 (0.05)	0.44 (0.01)	0.47 (0.04)	0.52 (0.08)	0.49 (0.07)	0.62 (0.04)	0.60 (0.01)	0.53 (0.09)
Tapped density (g/ml)	0.60 (0.07)	0.54 (0.01)	0.57 (0.08)	0.63 (0.04)	0.60 (0.02)	0.76 (0.03)	0.73 (0.02)	0.64 (0.07)
% Porosity	0.92 (0.095)	0.90 (0.089)	1.03 (0.019)	1.15 (0.049)	0.53 (0.099)	0.53 (0.045)	0.64 (0.043)	0.76 (0.063)
Hausner Ratio	1.24 (0.05)	1.23 (0.01)	1.23 (0.09)	1.23 (0.09)	1.23 (0.09)	1.23 (0.02)	1.22 (0.07)	1.22 (0.03)
Carr’s index (%)	18.33 (0.33)	18.51 (0.18)	17.54 (0.43)	17.46 (0.03)	18.33 (0.30)	18.42 (0.21)	17.80 (0.08)	17.18 (085)
Angle of repose(Ø ⁰)	28.35 (0.11)	27.68 (0.05)	27.05 (0.01)	26.62 (0.09)	28.30 (0.09)	27.89 (0.64)	27.38 (0.06)	26.68 (0.15)
Bulkiness	2.04 (0.08)	2.07 (0.02)	2.12 (0.07)	1.92 (0.03)	2.04 (0.08)	1.61 (0.02)	1.66 (0.06)	1.88 (0.06)

Values in parentheses represent SD, n=3

^aFormulation batches F1, F2, F3, F4 contains Pisum sativum seed powder with 3.3%, 6.6%, 13.3%, 20% binder respectively

^bFormulation batches F5, F6, F7, F8 contains Acacia with 3.3%, 6.6%, 13.3%, 20% binder respectively

Table 3: Physical qualities and in vitro availability parameters of lornoxicam tablets containing Pisum sativum seed powder and acacia as binders

Parameters	*Pisum sativum* seed powder^a				Acacia^b
% Binder (Batch)	3.3% (F1)	6.6% (F2)	13.3% (F3)	20% (F4)	3.3% (F5)	6.6% (F6)	13.3% (F7)	20% (F8)
Thickness (mm)	3.0 (0.1)	3.2 (0.1)	2.8 (0.2)	3.0 (0.1)	4.0 (0.1)	3.4 (0.2)	4.0 (0.1)	3.5 (0.2)
Volume of tablet	108.89 (0.05)	123.08 (0.08)	092.86 (0.05)	115.39 (0.05)	120.70 (0.01)	117.91 (0.02)	132.66 (0.05)	134.62 (0.07)
Packing fraction	0.80 (0.02)	0.72 (0.05)	0.94 (0.05)	0.75 (0.02)	0.73 (0.01)	0.72 (0.02)	0.65 (0.01)	0.65 (0.05)
Tensile strength	0.07 (0.01)	0.06 (0.02)	0.06 (0.02)	0.08 (0.01)	0.05 (0.03)	0.07 (0.01)	0.07 (0.02 )	0.06 (0.02)
Tablet physical stability	0.43 (0.06)	0.42 (0.03)	0.09 (0.06)	0.26 (0.01)	0.05 (0.06)	0.07 (0.06)	0.06 (0.08)	0.10 (0.03)
Content uniformity (%)	98.46 (1.4)	96.62 (1.8)	97.38 (1.3)	98.36 (0.9)	96.85 (1.1)	97.63 (1.3)	98.08. (1.4)	98.67 (1.2)
Weight variation (mg)	148 (1.2)	152 (0.8)	150 (2.1)	149 (2.0)	152 (1.6 )	151 (1.3)	149 (2.1)	150 (1.7)
Hardness (kg/cm² )	4.0 (0.1)	3.4 (0.4)	3.0 (0.2)	3.6 (0.1)	3.0 (0.3)	3.1 (0.2)	3.7 (0.1)	3.4 (0.2)
Friability (%)	0.36 (0.05)	0.56 (0.06)	0.24 (0.02)	0.37 (0.06)	0.32 (0.05)	0.45 (0.07)	0.38 (0.02)	0.46 (0.09)
Disintegration time(min)	3.30 (1.20)	4.50 (0.26)	3.05 (0.40)	5.10 (0.55)	17.12 (0.86)	18.31 (0.56)	20.50 (0.45)	15.18 (0.81)
*D_P* 30 Percent drug released at 30 min	48.53 (0.66)	37.66 (1.11)	45.48 (1.23)	37.18 (1.12)	50.45 (0.90)	72.38 (1.24)	50.4 (1.34)	41.6 (1.15)

Values in parentheses represent SD, n=3

^aFormulation batches F1, F2, F3, F4 contains Pisum sativum seed powder with 3.3%, 6.6%, 13.3%, 20% binder respectively

^bFormulation batches F5, F6, F7, F8 contains Acacia with 3.3%, 6.6%, 13.3%, 20% binder respectively

Figure 1: Comparative In-vitro Dissolution profile of Pisum sativum seed powder all batches, acacia all batches as binder.

The accelerated stability studies of the optimized formulations F3 and F8 unaffected after 3 months storage under accelerated conditions as no changes were observed in the FT-IR spectral analysis. Moreover, no signs of visually distinguishable changes were observed in the appearance, texture and color of the formulation. The data on hardness and disintegration were comparable with those of the control samples and were within the limits. F₂ values of 50–100 indicate similarity between the dissolution profiles. On the basis of these results, it may be concluded that the optimized formulations developed is stable under accelerated conditions for 3 months. This implies that Pisum sativum seed powders imparts required adhesive property to tablet granules.

CONCLUSION:

The results of the present study show that formulations containing the minimum concentration of 13.3% Pisum sativum seed powder as binding agent show short disintegration and fast dissolution including good physico-mechanical properties. These suggest that Pisum sativum seed powder could be useful as alternative binding agents, for lornoxicam tablet production.

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Received on 02.02.2014 Modified on 05.03.2014

Research J. Pharm. and Tech. 7(10): Oct. 2014 Page 1106-1110