Isolation of Starch from Navy Beans (Phaseolus Vulgaris) and Evaluation as Binder in Pharmaceutical Formulation

Navy bean (Phaseolus vulgaris)

Navy beans are a variety of (Phaseolus vulgaris) which is small oval shaped, white coloured legumes. Which are widely consumed as human nutrition, it is eaten in different forms, like dry mature beans, shell beans, and green pods. When it’s consumed as seeds or beans can be provide a significant source of dietary protein which is helps to balance the protein intake of people who rely on cereals. Navy beans an essential food source in different countries in worldwide in especially Latin America over half a billion people are consuming the beans as food source. (1)

Figure 1: Navy bean (Phaseolus vulgaris)

The leading producers of dry beans is India, Myanmar, USA, China, Brazil, Mexico, etc. globally annual production of dry beans are approximately 15 million tonnes. In India approximately 6.8 million metric tonnes dry /common beans are produced. Navy beans are a valuable pulse crop that contributes to food and nutritional security by offering an affordable source of plant-based protein, essential micronutrients like iron and zinc, as well as vitamins and dietary fiber. (2)  Navy beans (Phaseolus vulgaris), also known as haricot or white beans, are a rich source of starch and key carbohydrate with significant economic and nutritional value. The starch extracted from these nutrient-dense legumes displays important physicochemical properties influenced by factors like amylose-to-amylopectin ratio and starch structure. As consumer demand grows, identifying new starch sources is essential, and navy beans show great potential in this regard. Widely used in foods like soups, chili, casseroles, salads, and snacks, navy bean starch is valued for both its culinary versatility and health benefits. (3) A study of navy beans starches isolated from different methods and useful because different isolation methods may change some chemical, functional, and pasting properties of starch before the use. Starch is used not only in foods but also used in different industrial fields due to their multifunctional uses. The native or modified starches, pregelatinized and carboxymethyl starch are used in pharmaceutical industry because it’s binding capacity. (4) Starch is commonly used in pharmaceutical industry as binder, diluent, and disintegrant. Freshly and quality starch paste are used in tablet production and its concentration is 5-10%. When the production of solid dispersion tablet formulation then the concentration of starch is changes from 5-15%. The distinct properties of starch are improving the biocompatibility, biodegradability, and alteration of ability for potential usage. (5)

Morphological study: SEM characterization of Navy bean starch

Scanning Electron Microscopy (SEM) characterization of starch provides a detailed understanding of the surface morphology and structural integrity of starch granules, which is critical in assessing their functional and physicochemical properties. SEM allows for high-resolution imaging of starch granules at the micro to Nano scale, enabling the visualization of granule size, shape, surface texture, and any structural alterations due to processing or modification. (6)

Taxonomic identification:

Is essential for accurately naming and classifying plants, also an ensuring the clarity of research, agriculture, conservation and trade. It helps to avoid the confusion caused by local names, supports crop improvement and breeding programs, and is critical for conserving plant genetic resources.

1. Scientific Name-Phaseolus vulgaris
2. Common Name- Navy beans (haricot bean)
3. Family- Fabaceae (Leguminosae)
4. Tribe- Phaseoleae
5. Genus- Phaseolus
6. Species- vulgaris (7)                                                                                                    

Figure 2: Navy bean (Phaseolus vulgaris)

IDEAL PROPERTIES OF STARCH:

For pharmaceutical applications, especially as a binder, disintegrant, or filler in tablet and capsule formulations:

A. Physicochemical Properties

• High purity: Minimal levels of impurities such as proteins, lipids, or fibers.
• Fine and uniform particle size: Ensures even mixing and better tablet compaction
• Low moisture content: Reduces microbial growth and enhances shelf stability
• Appropriate gelatinization temperature: Facilitates controlled swelling and binding during Processing

B. Functional Properties

• Good binding ability: Capable of forming strong, cohesive tablets without additional   binders
• High compressibility: Allows the starch to form tablets under pressure without capping or lamination
• Flowability: Ensures uniform die filling during tablet compression
• Compatibility with APIs and other excipients: Chemically inert to avoid degradation. (8)

DRUG PROFILE: Diclofenac sodium

Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs are widely used to relieve inflammation, pain, and fever associated with conditions like arthritis, muscle injuries, and autoimmune diseases. NSAIDs, including ibuprofen and Diclofenac, work by inhibiting enzymes that produce prostaglandins chemicals that trigger inflammation. Treatment choice depends on the condition, symptom severity, and patient health. (8) Analgesic drugs, commonly known as painkillers, are used to manage both acute and chronic pain, improving patients' quality of life. They relieve pain without affecting consciousness or normal sensory functions. There are two main types: Non-opioid analgesics, such as Paracetamol and NSAIDs (e.g., Ibuprofen, Diclofenac, Aspirin), are used for mild to moderate pain and also reduce fever and inflammation. Opioid analgesics, including codeine, morphine, and tramadol, are stronger medications used for moderate to severe pain by binding to opioid receptors to block pain signals and alter pain perception. (9)

Drug profile:

• IUPAC Name: sodium;2-[2-(2,6-dichloroanilino) phenyl] acetate
• Molecular Formula: C14H10Cl2NNaO2
• Chemical structure:

• Appearance: white to off-white crystalline, slightly hygroscopic powder.
• Category: Nonsteroidal Anti-inflammatory Drug (NSAID)
• BCS Type: Class II (low soluble and high permeable)
• Molecular Weight: 318.1 g/mol
• Melting point: 283-285 C
• Bioavailability: 50- 60% (oral)
• Half-life: 1-2- Hours
• Brand name: Voltaren, Voltaren XR (extended-release), Zipsor, Zorvolex
• Storage: 200C to 250C

Objectives:

• To perform the isolation and extraction of starch by using dried Navy bean (Phaseolus vulgaris) seeds.
• To formulation of tablets by using a navy beans starch as binder.
• To comparative study between isolated navy bean starch and commercial maize starch.

METHOD OF PREPARATION

A pre-formulation study is a vital initial step in developing pharmaceutical dosage forms. It involves analyzing the drug's physical and chemical properties and its interactions with excipients. This helps predict performance during manufacturing and storage while guiding the development of stable, effective, and safe formulations. Key factors assessed include color, taste, odor, solubility, pH, particle size and shape, polymorphism, and melting point

Collection and authentication of plant material: The plant selected for present work, Navy beans (Phaseolus vulgaris) (Family: Fabaceae) was collected from Islampur, Dist. - Sangli, Maharashtra in November-December. The plant was identified and authenticated by Dept. of Botany, Yashwantrao Chavan College of Science, Karad, Maharashtra.

Isolation of starch:

Starch extraction from plants is a crucial process in both food and industrial applications. It typically begins with cleaning and preparing the raw material such as Navy beans, potatoes, cassava, or corn by washing and peeling. The material is then ground into slurry, often using a wet milling technique, to release the starch granules. This mixture is subjected to filtration or centrifugation to separate the starch from other components like fibers and proteins. The resulting starch is washed several times to remove impurities and then dried to obtain a pure, powdery form suitable for various uses. Different extraction methods, such as mechanical grinding, enzymatic treatments, or fermentation, can be employed depending on the source material and desired starch properties. These methods significantly impact the yield, purity, and functional characteristics of the extracted starch. (10) Isolation of starch from Navy bean (Phaseolus vulgaris) by using different methods.

1. Isolation by using sodium chloride (NaCl) method
2. Isolation of starch by using sodium metabisulphite (Na2S2O5) method
3. Isolation and extraction of starch by using enzyme-assisted ultra-sonication method

Isolation using Sodium metabisulfite:

Starch was extracted from the selected starchy material by first blending the starch-rich sources with water at a 1:10 ratio until smooth slurry was obtained. During this process, 0.01% (w/v) Sodium metabisulfite was added to prevent oxidation and discoloration. The resulting slurry was initially filtered through double-layered cheesecloth, followed by sequential filtration using polypropylene screens of 250, 175, 125, or 75 µm pore sizes. The filtrate was then centrifuged at 5000 × g for 20 minutes at 20°C. The starch, which settled at the bottom of the centrifuge tube, was washed with toluene to remove impurities, then oven-dried at a temperature between 30°C and 40°C. Finally, the dried starch was ground into a fine powder using a mortar and pestle. (11)

Isolation using Sodium chloride:

 In this method, the starchy material is cut into small pieces and blended with a 1 M sodium chloride (NaCl) solution to form a uniform mixture. The mixture is then filtered through triple- layered cheesecloth to remove solid residues. The filtrate is thoroughly washed with distilled water to eliminate excess salt and impurities. The starch suspension is allowed to settle, and the clear supernatant is carefully decanted. The starch-rich sediment is then centrifuged at 3,000 × g for 10 minutes. The recovered starch is air-dried overnight at room temperature and subsequently ground into a fine powder using a mortar and pestle. (12, 13)

Enzyme-Assisted Ultra-Sonication Method:

 In this method starch extraction begins with cleaning and drying navy bean seeds, which are then ground into a fine powder. This powder is mixed with distilled water to form slurry. Specific enzymes, such as cellulase or protease, are added to the slurry and incubated at an optimal temperature (typically 40-55°C) for 30 to 60 minutes. These enzymes help break down the cell walls and proteins, loosening the starch granules. After enzymatic treatment, the slurry is subjected to ultra-sonication using a probe sonicator at a frequency of around 20-40 kHz for 15 to 30 minutes. This ultrasonic energy further disrupts cell structures and improves the release of starch. The treated mixture is then filtered to remove solid residues, and the filtrate is centrifuged at 1000-3000 rpm for about 10-15 minutes to collect the starch as sediment. The starch is washed several times with distilled water to eliminate any remaining impurities. Finally, the purified starch is dried in a hot air oven at 40-50°C until completely moisture-free and stored in an airtight container for further use. (14, 15)

Drug and Starch Characterization: Colour, Odour, taste

Physicochemical properties of Navy bean starch:

Melting point determination, Chemical test for Starch, Moisture Content, Ash Content, Viscosity, Water Absorption Capacity (WAC), Oil Absorption Capacity (OAC), and pH.

Melting point Determination: To determine the melting point, a small amount of powdered sample is packed into a capillary tube and placed in a melting point apparatus. The temperature is gradually increased, and the range from when the sample starts to melt to when it completely liquefies is recorded as the melting point.

Starch identification iodine test: is a simple and widely used method for identifying the presence or absence of starch in a given sample. To perform the test, a few drops of iodine solution (commonly iodine dissolved in potassium iodide) were added to the material being tested. (16)

Moisture content determination: To determine the moisture content of starch, about 5 grams of the starch sample is weighed in a clean, dry crucible. The sample is then placed in a hot air oven at 105°C and dried for 3 to 4 hours until a constant weight is achieved. After drying, the sample is cooled in a desiccator and weighed again. The moisture content is calculated using the formula:

Moisture (%) = [(Initial weight – Final weight) / Initial weight] × 100.

This method helps assess the amount of water present in starch, which is important for storage and quality control.

Ash content determination: To determine the ash content of starch, a clean, dry crucible is weighed. A known amount (2-5 grams) of starch is added to the crucible and weighed again. The sample is then placed in a muffle furnace at 550-600°C and heated for 4-6 hours or until all the organic material is combusted, leaving a white or gray ash residue. After cooling in a desiccator, the crucible with ash is weighed again. The ash content is calculated using the formula:

Ash (%) = [(Weight of ash) / (Weight of sample)] × 100.

This method provides an estimate of the inorganic mineral content in the starch sample. (17)

Viscosity of starch: To measure the viscosity of starch, a specific amount of starch is first weighed and mixed with a measured volume of water to form a suspension. This mixture is then gradually heated while being continuously stirred until it reaches the gelatinization temperature, usually between 70°C and 90°C, depending on the starch type. As the starch gelatinizes, it thickens and forms a paste. After heating, the mixture is slightly cooled if necessary and transferred to a Brookfield viscometer or Rapid Visco Analyzer (RVA), where the viscosity is recorded over time at different temperatures. This allows for the assessment of the starch's thickening behavior under controlled conditions. (18, 19)

Water absorption capacity (WAC) was determined by mixing 3 g of separated starch with 50 mL of distilled water in pre-weighed centrifuge tubes. The mixture was centrifuged at 3000 × g for 30 minutes to separate the starch from the supernatant. After centrifugation, the tubes were reweighed, and the supernatant was carefully decanted. WAC was calculated as the amount of water absorbed per gram of sample using the following formula. (20)

Formula: WAC g H2 O=W2-W1W0×100

Where W2 = Weight of tube plus the sediment (g), W1 = Weight of the tube plus dry sample (g), and W0 = Weight of the dry sample (g)

Oil absorption capacity (OAC): The oil absorption capacity (OAC) of navy bean starch was determined by adding 1 g of separated starch to 10 mL of vegetable oil in a pre-weighed 20 mL centrifuge tube. After agitating the mixture for 2 minutes to ensure complete dispersion, the tubes were left to stand at 28°C for 30 minutes, and then centrifuged at 3000 × g for another 30 minutes. The supernatant was decanted, and the tubes were inverted for 25 minutes to drain excess oil before being reweighed. OAC was expressed as the amount of oil absorbed per gram of starch, calculated using the following formula. (20, 21)

Formula: OAC g H2 O=O2-O1O0×100

Where W2 = Weight of tube plus the sediment (g), W1 = Weight of the tube plus dry sample (g), and W0 = Weight of the dry sample (g)

Solubility test of starch: The solubility of Navy bean starch was determined in various solvents. (22)

UV-visible spectrophotometric analysis: UV spectroscopy: The UV spectrum of Diclofenac sodium and Navy bean starch was obtained. Shimadzu UV1900i Spectrophotometer and spectra manager software was used for analysis.

SEM characterization of Navy bean starch: Scanning Electron Microscopy (SEM) characterization of Navy bean starch provides a detailed understanding of the surface morphology and structural integrity of starch granules, which is critical in assessing their functional and physicochemical properties.

Drug Excipients compatibility study:

Drug Excipients compatibility studies represent an important phase in drug development. Before a drug substance is formulated into a desired dosage form, there is need for the formulator to fully consider the chemical structure of the drug substance, type of delivery system required and the proposed manufacturing process.

Table 1: Drug – Excipients compatibility study Ratio

FT-IR of Drug and all Excipients: 

FTIR spectroscopy serves as an essential tool in the preformulation stage of drug development. By identifying potential chemical interactions between APIs and excipients, it aids in the selection of compatible components, ensuring the stability and efficacy of pharmaceutical formulations. Incorporating FTIR analysis into the formulation development process can significantly reduce the risk of formulation failures due to incompatibilities.

Comparative study Navy bean starch with Maize starch:

Comparison of isolated Navy bean starch and marketed Maize starch.

Micromeritics properties of starch:

Bulk Density: Powder blend was accurately weighed & passed through sieve # 80 and was carefully poured into 100 ml graduated cylinder. The capacity was calculated as ml using the graduation marking on cylinder. The bulk volume is a volume measurement and the bulk density is determined using the formula below. (23)

Formula: Bulk density (g/ml) -   ρb = MassVolume

Tapped Density: After measuring the bulk volume, the same measuring cylinder containing the powder blend was set into tap density apparatus and was mechanically tapped, allowing it to drop under its own weight that provides a fixed drop from 14±2mm. The tap density apparatus was run for 500 taps volume was recorded as (Vt). The following formula is used to determine tap density. (23)

Formula: Tapped Density (g/mL) - ρt = Massfinal tapped Volume

Flow Properties: Flow assessment of API and Excipients made to ensure that the powder will flow adequately through processing equipment’s such as compactor, hopper or tablet press.

Compressibility index (C.I.): It is the measure of propensity of a powder to consolidate. It is the measure of inter particulate interaction in free-flowing powder, such interaction is generally less significant and BD and TD value will be close. For poor flowing material it causes frequently greater inter particle interaction, bridging between particles often results in lower bulk density and greater difference between BD and TD and this difference is reflected in compressibility index. (24)

Formula: Carr’s index - CI=100×ptapped-pbulkptapped

Hausner’s ratio: Hausner’s ratio is a measurement used to describe the compressibility of powder. It was the ratio of tapped density to bulk density. (26)

It is calculated by the formula: Hausner’s ratio = ptappedpbulk

Angle of Repose: The angle of repose is a critical parameter that indicates the interparticulate friction and flowability of powders. Using the fixed funnel method, a powder sample is allowed to flow through a funnel onto a flat, vibration-free surface with a retaining lip. The height (h) and base diameter (D) of the resulting conical pile are measured. The angle of repose (θ) is then calculated using the formula: (24)

Angle of repose = tan-12hd-h

DESIGN OF EXPERIMENT (DOE):

The application of Design of Experiments (DoE) in tablet formulation development provides a structured approach to optimize critical formulation and processing parameters. Utilizing techniques such as Factorial Design, Response Surface Methodology (RSM), and Mixture Designs, researchers can systematically evaluate the effects of multiple variables and their interactions on tablet quality attributes.

Preparation of Diclofenac sodium tablets

Preparation of Diclofenac sodium 200 mg immediate release tablets using Navy bean starch as a natural binder via wet granulation method. Wet granulation method is widely used in pharmaceutical industry to improve the flowability, compressibility, and uniformity of tablet formulations.

Table 2: Ingredients used for Diclofenac table preparation

Formulation of Diclofenac sodium tablet by wet granulation method:

The objective of this pharmaceutical development activity was to develop stable formulation of Diclofenac sodium Tablets by using a Navy beans (Na2S2O5) method starch as a binder, USP 200 mg immediate release tablet.

Table 3: Standard formulation Table

Pre compression parameters:

Pre-compression evaluation of tablet granules is essential to ensure proper flow, compressibility, and uniformity before tableting. Key parameters include angle of repose, bulk and tapped density, Carr’s index, and Hausner’s ratio, which help assess flow properties. These parameters are evaluated to ensure proper granule formation and stability. These parameters collectively ensure smooth tablet manufacturing and consistent quality.

Post Compression Parameters

Tablets are evaluated as per Pharmacopeial specification.

1. Weight of tablet: Twenty tablets randomly selected from each batch and individually weighed. The average weight and standard deviation of 20 tablets was calculated.
2. Tablet dimensions: Thickness and diameter of the tablets were measured using a Vernier caliper. It was determined by checking ten tablets from each formulation. It is expressed in mm.
3. Physical appearance: The appearance of the core tablet i.e., surface texture, chipping and cracks if any were observed. (25)
4. Hardness: For each formulation, the hardness of tablets was determined using the Monsanto hardness tester. The 10 tablets were held along its oblong axis in between the two jaws of the tester. At this point, reading should be zero kg/cm2.
5. Disintegration time: In vitro disintegration time of tablets from each formulation was determined by using disintegration apparatus USP. In vitro disintegration test was carried out at 37.2?C in 900 ml by using disintegration media. 6 tablets of each formulation were taken and placed in tubes of disintegration apparatus. The time taken for complete disintegration was noted. (26)
6. Friability: Friability refers to a tablet’s resistance to abrasion caused by friction and shock, which can lead to chipping, capping, or breakage. This property, closely related to hardness, was assessed using a Roche Friabilator. Twenty pre-weighed tablets were placed in the device and subjected to 100 rotations (or 4 minutes), during which they were repeatedly dropped from a height of 6 inches. After the test, tablets were reweighed, and friability was calculated using the formula (26)

% Friability = (W1 − W2) / W1) × 100)

Where W1 is the initial weight and W2 is the final weight.

7. Drug content test: The drug content test (assay) determines the amount of active pharmaceutical ingredient (API) in a tablet to ensure it meets specified limits, typically 90–110% of the labeled claim according to pharmacopoeial standards like USP, BP, and IP. The procedure involves accurately weighing and crushing ten tablets into a fine powder. A portion equivalent to one tablet is then dissolved in a suitable solvent, such as methanol or buffer, and sonicated or shaken to ensure complete dissolution. The solution is filtered to remove any insoluble particles, and appropriate dilutions are made to obtain the required concentration. The final solution is analyzed using a UV spectrophotometer or HPLC, comparing it with a standard solution, and the drug content is calculated as a percentage of the labeled amount. (27)
8. Dissolution time: In-vitro dissolution studies for immediate release tablets of Diclofenac sodium were carried out using USP apparatus type II at 100 rpm. The dissolution medium used was phosphate buffer 6.8 pH solution (900 ml) was used as dissolution medium for up to 1 hr. and maintained at 370C ± 0.50C.  Aliquots of dissolution media were withdrawn (10 ml) at every 5-10min. intervals and content of Diclofenac sodium was measured by determining absorbance at 279 nm, using- visible spectrophotometer. (28, 29)

STABILITY STUDY:

The optimized formulation was wrapped in aluminum foil and subjected to 30 ± 50C temperature and 70 ± 5% RH in stability chamber for the period of 2 month. The formulation was analyzed for organoleptic characteristics, Thickness, Hardness, Drug content and Dissolution testing. In any rational design of dosage forms for drug, the stability of the active component is the major criteria in determining their acceptance or rejection. Stability studies were carried out as per ICH Q1A (R2) guidelines. (30)

RESULT AND DISCUSSION:

Isolation of starch

Isolation of starch from navy beans (Phaseolus vulgaris) using different extraction methods.

1. Isolation by using sodium chloride (NaCl) method
2. Isolation of starch by using sodium metabisulphite (Na2S2O5) method
3. Isolation and extraction of starch by using enzyme-assisted ultra-sonication method

Table 4: Isolated starch percentage

The average percentage of starch content in Navy beans is 22.53 %

Organoleptic characterization of drug and isolated starch:                        

Table 5: Observation table of organoleptic characterization

Physicochemical properties of Navy bean starch: The extraction method significantly influences the physicochemical properties of Navy bean starch. Na2S2O5 extraction resulted in starch with higher WAC, making it suitable for applications requiring water retention. NaCl extraction produced starch with higher OAC, beneficial for applications needing oil absorption. Enzyme-assisted ultra-sonication provided a balance between moisture content and functional properties.

Table 6: Starch Moisture and Ash content

Chemical Test for Navy bean starch:

The iodine test was conducted to detect the presence of starch in the sample. Upon adding iodine solution (Lugol's iodine), a characteristic blue-black coloration developed, indicating the presence of starch.

Table 7: Starch Chemical Test Table

Observation:

(+) Test shows present of test.

(-) Test shows absent or no observation of test.

Melting point determination: Melting point of Diclofenac sodium and isolated starch was determined to be, in range (283-285 ?C (Diclofenac sodium) & 254- 258?C (Navy bean starch starch) Hence the drug and isolated Navy bean starch can be stated as pure.

Table 8: Melting point determination

Solubility of Navy bean starch: The solubility of starch is temperature-dependent, and gelatinization is the key process that allows starch to become soluble in water.    

Table 9: Solubility study of Navy bean starch

UV-visible spectrophotometric analysis:

Methanol were used as solvent system for determination of λ max 10 µg/ml of Diclofenac sodium sample was used and λ max was found as 279 nm for methanol. Hence 279 nm selected as λ max for further studies.

Table 10: Calibration Curve

Figure 2: UV spectrum of Diclofenac sodium

Figure 3: Calibration curve of Diclofenac sodium in methanol

SEM characterization of Navy bean starch:

Navy bean starch was analyzed for morphological characterization using Scanning Electron Microscopy, The SEM image of the navy bean starch are mentioned in Figure (A, B). The navy bean starch show smooth and oval shapes with no irregular surfaces and the size of particles were noticed to be up to 10-100 nm.

Figure 4.1 (A)

Figure 4.2 (B)

UV of Navy bean starch:     

DMSO (dimethyl sulfoxide) were used as solvent system for determination of λ max 10 µg/ml of Navy bean starch sample was used and λ max was found as 271 nm.

Table 11: Wavelength and Absorbance of Navy bean starch

Figure 5: UV spectrum of Navy bean starch

Drug - Starch compatibility study:

The FTIR Spectra of drug and all excipients in pure form and their physical mixture was observed; the result showed that there was no interaction between drug, starch and Excipients.

• IUPAC Name: sodium; 2-[2-(2,6-dichloroanilino) phenyl] acetate
• Molecular Formula: C14H10Cl2NNaO2
• Chemical structure:

IR of Diclofenac sodium and Navy bean starch:

The IR spectrum of Diclofenac sodium and Navy bean starch was recorded on Shimadzu IRAffinity-1.

Figure 6 (A): IR of Diclofenac sodium

Figure 6 (B): IR for Navy bean starch

Figure 6 (C): IR of Navy bean starch & Diclofenac sodium

Figure 6 (D): Overlay of drug & Excipients compatibility

Comparative study Navy bean starch with Maize starch:

A. Micrometrics properties evaluation: Comparison of Isolated Navy bean starch and Marketed Maize starch.

Table 12 (A): Micrometrics properties of Maize starch

Table 12 (B): Micrometrics properties of Navy bean starch

Both powder samples exhibit Good to Excellent flowability, making them suitable for pharmaceutical applications such as tablet compression and capsule filling. The slight differences in bulk and tapped densities are minimal and do not significantly impact on their Overall flow properties.

Table 13: Comparative study of Maize starch and Navy bean starch

Both starches have similar iodine reactions and melting points, but Navy bean starch has slightly higher moisture content and moderate viscosity, while Maize starch has a higher viscosity.

FORMULATION STRATEGY:

As per Design of Experiments (DOE) approach was employed to prepare and evaluate all 9 batches of Diclofenac sodium tablets using Navy bean isolated (sodium metabisulphite method) starch as a binder.

Table 14: Formulation strategy

EVALUATION OF FORMULATED BATCHES:

A. Pre compression parameters:

The powder blend from all the batches were evaluated for density and flow property parameters which includes Bulk density, Tapped density, Compressibility index, Hausner’s ratio and Angle of repose.

Table 15: Pre-compression parameters

All nine batches (F1–F9) exhibit Good flowability based on their Carr’s Index, Hausner’s Ratio, and Angle of Repose values. These characteristics suggest that the powders have low interparticle friction and are suitable for further processes requiring good flow properties for tablet compression.

Post Compression Parameters:

Table 16: Post compression parameters

Evaluation of the nine tablet batches (F1–F9), it was observed that all formulations exhibited consistent physical dimensions and met the pharmacopoeial standards for friability, hardness, disintegration time, and drug content Hardness values varied across batches, with higher values correlating to increased disintegration times.

Optimization of all batches:

Design Expert 7.0 software was used to examine how independent variables affected the results. The experimental design pattern was created for nine potential batches of Diclofenac sodium tablets. The software recommended several models, including Linear, 2FI, Quadratic, and Cubic, which fit well and were examined using analysis of variance (ANOVA).

The interaction terms between X1 and X2 demonstrate how the response changes when both factors are altered simultaneously.

Table 17 (A): The layout of the Actual Design of DOE

Table (B): Optimized batch

The formulation of optimized batch F8, incorporating 40% navy bean starch and 60% lactose, was designed to leverage the complementary properties of these excipients. Navy bean starch, recognized for its excellent disintegrant properties, facilitates rapid tablet breakdown upon contact with moisture, ensuring swift drug release.

In vitro dissolution test of optimized batch (F8):

The prepared batches and optimized batch F8 were evaluated in vitro. Using the corresponding equation of line, the dissolving medium and percentage of drug release in phosphate buffer 6.8 pH were ascertained. Table 7.24 presented the findings.

Table 18: In vitro dissolution % of optimized batch (F8)

Table 19: Release kinetic model fitting

The Krosmeyer- Peppas model provides the best fit for the drug release behavior, based on the high R² value and appropriate parameters.

Figure 7 (A): Zero order kinetics

Figure 7 (B): First order

Figure 7(C): Higuchi release kinetics

Figure 7 (D): korsmeyer-peppas model

Evaluation after stability study of optimized batch (F8):

Evaluation and Stability data of Diclofenac sodium tablet of formulation F8 are given below

Table 20: Evaluation and stability study of optimized batch (F8)