Guava (Psidium guajava) Leaf - Based Tablet: A Novel Approach for Diabetes

Diabetes mellitus is a long-term disease that happens when the body cannot make enough insulin or use it properly. This leads to high levels of sugar in the blood, which, over time, can damage organs like the heart, kidneys, eyes, and nerves. The number of people with diabetes is increasing worldwide, and managing the disease often requires daily medication, diet control, and regular monitoring. However, many diabetes medicines can have side effects and may be expensive, especially for long-term use.

Because of this, there is growing interest in natural and herbal treatments that are safer, cheaper, and easier to access. One such plant is guava (Psidium guajava), which is commonly grown in tropical regions. While guava fruit is well-known, its leaves also have important health benefits. Guava leaves contain natural compounds like flavonoids and tannins, which have been shown in studies to help lower blood sugar levels, reduce inflammation, and fight harmful bacteria.

In traditional medicine, guava leaf tea has been used to help treat diabetes and other illnesses. In this study, we aim to make guava leaf powder into tablet form, which is easier to take, store, and dose. We will test the physical quality of the tablets and check how well they work in controlling blood sugar by performing laboratory tests. This research could help develop a natural and affordable supplement for people with diabetes, especially in areas where access to modern medicine is limited.

Advantages of guava leaf powder:

1. Helps lower blood sugar
2. Improves digestion
3. Fights bacteria and infections
4. Reduces inflammation
5. Supports heart health
6. Rich in antioxidants
7. Natural and affordable remedy

Disadvantages of guava leaf powder:

1. May cause stomach upset if taken in large amounts
2. Not enough research on long-term use
3. May interact with some medicines
4. Not recommended for pregnant or breastfeeding women without doctor’s advice
5. Allergic reactions are possible in rare cases

Drug profile:

Drug Name :- Guava

Biological Name:- Psidium guajava

Family :-  Myrtaceae

Chemical constituents:-

Flavanoids : Quercetin, Kaempferol, Rutin

Tannins: include both hydrolyzable tannins and condensed tannins, contributing to antioxidant and antimicrobial activity.

Terpenoids : Oleanolic acid and ursolic acid

Saponins: Saponins contribute to cholesterol-lowering effects and also exhibit antimicrobial and immune-enhancing activities.

Phenolic Compounds : gallic acid, ellagic acid, and catechin,

Essential Oils : Eugenol, limonene

Alkaloids : present in smaller quantities

Microscopic Structure:-

T.S of Guava Leaf

Macroscopic characteristics:

Shape: Oblong to elliptic or oval

Size: Approximately 5–15 cm in length and 3–7 cm in width

Color: Dark green on the upper surface and lighter green on the lower surface

Mechanism of Action: Guava (Psidium guajava) leaf powder tablets exert antidiabetic effects through multiple complementary mechanisms involving both insulin-dependent and insulin-independent pathways. The primary bioactive constituents responsible include flavonoids (quercetin, kaempferol, rutin), tannins, and phenolic compounds.

Guava (Psidium guajava) leaf powder tablets exert antidiabetic effects primarily by inhibiting carbohydrate-digesting enzymes such as α-amylase and α-glucosidase, thereby reducing postprandial blood glucose levels. Additionally, flavonoids like quercetin enhance insulin sensitivity and promote glucose uptake in tissues. The antioxidant properties of the leaves also protect pancreatic β-cells from oxidative damage, supporting insulin secretion.

Mechanism of Action:-

Guava (Psidium guajava) leaf powder tablets exert antidiabetic effects through multiple complementary mechanisms involving both insulin-dependent and insulin-independent pathways. The primary bioactive constituents responsible include flavonoids (quercetin, kaempferol, rutin), tannins, and phenolic compounds.

Guava (Psidium guajava) leaf powder tablets exert antidiabetic effects primarily by inhibiting carbohydrate-digesting enzymes such as α-amylase and α-glucosidase, thereby reducing postprandial blood glucose levels. Additionally, flavonoids like quercetin enhance insulin sensitivity and promote glucose uptake in tissues. The antioxidant properties of the leaves also protect pancreatic β-cells from oxidative damage, supporting insulin secretion.

Nutritional values of guava:

Identification Test:-

At first we performed the Identification/Authentification test of the given powder sample, on the basis of the above given chemical constituents the identification test of the powder sample was performed. Here we considered the major chemical constituent of moringo olifera leaf powder as Alkaloid, on the basis of this we performed the Phytochemical Screening of Extract.

Detection of Alkaloids:- Extracts were dissolved individually in dil. Hydrochloric acid and filtered. The filtered acidified extracts were then subjected to the following tests:

Chemical Test for Alkaloids:

Detection of Lipid:

Detection of Cardiac glycoside: killer kiliani Test:

The Ash value test is a crucial analytical procedure used to assess the quality and purity of crude drugs, particularly when they are in powdered form.

Ash value Test

Purpose: To determine the total inorganic content in the Crude drug

Procedure:

• Weigh approximately 5 grams of the powdered drug In a tarred silica crucible.

• Gradually increase the heat using a muffle furnace Until the sample is free from carbon.

• Cool the crucible and weigh the resulting ash.

• Calculate the percentage of total ash relative to the Air-dried sample.

Significance: The total ash reflects the care taken During drug preparation.

Weight of sample powder = 3 gm

Total Ash value = 0.76 gm

Ash Value (%) = (Weight of Ash / Weight of sample) × 100

Ash Value (%) = (0.76 / 3) × 100

Ash Value (%)  = 25%

Acid Insoluble Ash(%) = (weight of acid Insoluble Ash / Weight of sample) ×100

= (0.48/3) ×100

Acid Insoluble Ash(%) = 17 %

Preformulation:

Preformulation testing is the first step in the rational development of dosage forms of a drug substance. It can be defined as an investigation of physical and chemical properties of a drug substance alone and when combined with excipients. The overall objective of preformulation testing is to generate information useful to the formulator in developing stable and bioavailable dosage forms that can be mass produced. Preformulation investigations are designed to deliver all necessary data especially physicochemical, physico- mechanical and bio pharmaceutical properties of drug substances, excipients and packaging materials.

Objectives of preformulation study:-

1. To understand the physicochemical properties of the drug substance.

2. To develop the elegant dosage forms (stable, effective & safe)

3. To save time and money by avoiding problems in later stages of development.

4. To help decide the best way to give the drug – like tablet, injection, or syrup.

5. To make sure the drug will work well in the body and stay safe and effective.

6. To check if the drug can be compressed into a solid form like a tablet.

7.To check if the drug reacts with other ingredients used in the formulation.

8. To find out how well the drug dissolves in water or other liquids

Goals of preformulation:

1. 1. To avoid problems later during large-scale production.
   2. To support smooth approval from drug regulatory authorities.
   3. To establish the physico-chemical parameters of new drug substance.
   4. To establish the physical characteristics
   5. To establish the kinetic rate profile.
   6. To establish the compatibility with the common excipient.
   7. To choose the correct form of a drug substance.

Preformulation Parameters:

A. PHYSICAL CHARACTERISTICS

1) Organoleptic Properties

2) Bulk Properties

a) Solid State Characteristics

b) Flow Properties

c) Densities

d) Compressibility

e) Crystalline

f) Polymorphism

g) Hygroscopicity

3) Solubility analysis

a) Ionization constant (Pka)

b) Partition co-efficient

c) Solubilization

d) Thermal effect

e) Common ion effect (Ksp)

f) Dissolution

B) CHEMICAL CHARACTERISTICS

1) Hydrolysis

2) oxidation

3) Photolysis

4) Recemization

5) Polymerization

6) Isomerisation

Organoleptic Characteristics:

These includes the all the physical characteristics of the powder. These properties are easily can be visualize by naked eyes. It includes size, shape, color, odour of the powder.

Guava Leaves Powder

Flow rate:-

Flow rate depends upon the particle size, surface area and porosity.

Flow rate = Mass/Time

Flow rate = 0.50  m³/s

Bulk Density:

Bulk density, also known as apprent density, iss a material property defined as the mass of the material divided by the bulk volume.

     Bulk density= Mass ( m )/Bulk Volume

Mass= 19.50 g ; Volume= 50 cm³

Bulk density= 19.50 /50

Bulk density=  0.30 gm/ cm³

Tap Density:

Tap density refers to the bulk density of a powder sample after it has undergone a process of tapping or vibration for a defined period.

Defination:

Tapped density is the density achieved after external force is applied to a container filled with powder. The goal is to remove any voids or spaces between the particles .

Tap density= Mass/Volume

Here, Mass= 19.50 ; Volume= 34 cm³

     Tap density= 19.50 / 34

 Tap density=  0.57 gm/ cm³

Carr’s Index=

The Carr Index and the Hausner Ratio are both meant as being indicators of the Bowability of bulk solids. It is thus not always obvious to characterize the solid flowability with the few set of data that Engineers usually have in hand during design or troubleshooting.

Both Carr and Hausner attempted just that: assuming that the compressibility of a solid is related to its flowability, they proposed to measure the and calculate a ratio in order to estimate how the material will flow.

The lower the Carr Index or Hausner Ratio, the more flowable is a material

Carr’s Index formula :

Carr’s Index = (0.57-0.39/0.57) × 100

Carr’s Index = 39

Hausner’s ratio=

                    Hausner’s ratio formula

     H= Tap density/ Bulk density

            =  0.57 /0.39

        Hausner’s ratio = 1.45

It is passable

Angle of repose=

Maximum angle possible between the surface of pile of powder sample and horizontal plane.

Where, h= Height of powder sample

              R= Radius of circle

          Θ = 42

It is Passable

Flowchart of Tablet formulation:

1. Collection of Guava Leaves

                              ↓

2. Washing with clean water

                              ↓

3. Shade Drying (Room Temperature, 2-3 days)

                               ↓

4. Pulverization ( Using Grinder/Mill)

                               ↓

5. Sieving (To obtain fine powder)

                               ↓

6. Weighing of power

                                ↓

7. Mixing with excitements ( e.g., binder, filler, lubricant)

                                 ↓

8. Granulation ( wet/dry granulation used)

                                 ↓

9. Drying of granules ( If wet granulation used)

                                 ↓

10. Compression into Tablets (Using Tablet Press)

                                 ↓

11. Quality Control Tests ( e.g., Weight variation, Hardness, Disintegration)

                                 ↓

12. Packaging and Storage

Tablet formulation:

A tablet is a solid dosage form commonly used for oral administration. It consists of one or more active substances (the drugs or therapeutic agents) along with other excipients These excipients play crucial roles in shaping the tablet’s properties and ensuring its effectiveness. Here are the key components involved in tablet formulation:

1. Active Pharmaceutical Ingredient

Guava leaves powder is the main active Pharmaceutical Ingredient in the tablet formulation on the diabetes mellitus treatment.

In these we use guava leaves powder.

Psidium guajava leaves, consisting mainly of:

• Polyphenols
• Flavonoids (especially quercetin)
• Tannins
• Terpenoids
• Saponins
• Essential oils

It shows its activity as follows :

Antidiabetic: Inhibits alpha-glucosidase and enhances insulin sensitivity.

2. Excipients:

Diluent:

These provide bulk to the tablet and ensure uniformity in size.

Common examples include lactose, microcrystalline cellulose, and starch.

Lactose :- To provide bulk and aid in tablet formation, especially important for herbal powders which may have poor flow or compressibility.

Binders:

Binders hold the tablet ingredients together, ensuring proper cohesion.

They enhance tablet strength and prevent disintegration during handling and storage.

Examples include:-  hydroxypropyl cellulose, polyvinylpyrrolidone (PVP), and starch paste.

Starch paste is mainly used in these formulation because it have a best binding property.

And the are form without any errors.

Disintegrants :-

Disintegrants are essential excipients used in tablet formulations to promote the breakup of the tablet into smaller fragments upon contact with gastrointestinal fluids. This enhances the dissolution and bioavailability of the active herbal constituents in  Guava.

E.g:- Starch

Starch works by swelling upon contact with gastrointestinal fluids, causing the tablet to break apart into smaller fragments, which increases the surface area for dissolution.

Lubricants:

Lubricants are vital excipients used to reduce friction between the tablet material and the surfaces of manufacturing equipment during compression and ejection. This ensures smooth tablet formation and prevents sticking or damage to the punches and dies.

Magnesium Stearate – The most widely used lubricant due to its excellent hydrophobic properties.

Glidant

When formulating Guava  leaf tablets, a glidant is used to improve the flow properties of the powder blend before compression. This helps ensure uniform tablet weight and consistent active ingredient content.

Preservatives:-

When formulating Guava  leaf tablets, preservatives are typically added to extend shelf life, prevent microbial contamination, and maintain product quality. However, since guava is a natural health product, it’s important to use safe, food-grade or pharmaceutical-grade preservatives that align with clean label standards.

Ideal properties of preservatives:-

1. Solubility: Should be sufficiently soluble in the formulation medium (e.g., water for aqueous systems, oil for lipid-based systems).
2. Should be Non-Volatile and Heat-Stable
3. Effective at Low Concentrations
4. Cost-effective for large-scale production and readily available
5. Effective against a wide range of microorganisms including Gram-positive and Gram-negative bacteria, yeasts, and molds.
6. Should have Chemical and Physical Stability.

Functions of preservatives:-

1. 1. Prevent growth of germs – They stop bacteria, fungi, and mold from growing in the tablet or in any moisture around it.
   2. Keep the tablet safe – They help make sure the medicine stays safe to use and doesn’t cause infections or harm
   3. Increase shelf life – They help the tablet last longer without going bad.
   4. Protect ingredients – They stop the active ingredients and other parts of the tablet from breaking down too early

Following Excipients are used in mentioned quantity in the tablet formulation:-

  Above quantities are taken as of for 50 tablets

As per the required quantity the API and other excipients were weighed properly with appropriate measurements. After these process further the method of granulation is started . As per the formulation we decided to go with the wet granulation method as it gives compaction and strong stability of the product. The quality and flowability of granules is also enhanced by wet granulation method

Granulation method:

Granulation is a fundamental process in pharmaceutical Formulation used to convert fine powders into larger, Free-flowing granules. This technique improves the flow Properties, compressibility, content uniformity, and Stability of the final product.

There are two primary types of granulation:

1. Wet granulation method
2. Dry granulation method

Granulation Method For guava Leaf Powder Tablet :- Granulation is a critical step in the formulation of herbal Tablets, particularly for powders such as guava  leaf powder, which may possess poor flow and Compressibility properties. In this study, the wet Granulation method was employed to enhance the Physicomechanical characteristics of the guava leaves Powder.

Wet granulation method is used in the formulation of Guava  leaf powder tablets.

Procedure for weight Granulation:

1.Weigh accurately API and all the excipients Properly.

2.Pass the APl and excipients through the seive no.80

3.In a beaker make a binder solution using starch and Water, take 5 gm of starch in 50 ml of water and Keep it on heating mattle until slurry is formed.

4.In a mortle pestle take a API and lactose mix them Properly

5.blend it uniformly until and unless all the Excipients Are mixed properly.

6. Then add the binder solution slowly with constant Mixing as per need.

7.Mix them well unitll a damp mass is formed.

1. 8. Pass the wet Mass through the 20 number seive

Then we get the granules from the wet granulation Method.

Overall Procedure of Tablet formulation:

1) Firstly the leaves of  Guava leave are taken

2) The leaves are extracted the other particles with The leaves obtained are Removed

3) The leaves are washed with the Distilled water 2 or 3 times

4) The washed leaves then shade dried for some time Until they completely they get wholly dry.

5) All moisture will get removed because of it.

6) The dried leaves then grind to form the fine Powder.

7) These powder is then passed through the 80 Number seive.

8) Then appropriate weight of powder is taken by Weighing it

9) All the Excipients also weighed

10) Firstly the Powder is taken in the mortar and Pestle

11) Lactose and other excipients are added in it

12) Blend it until all the all excipients uniformly get Mix

13) Add binder solution which is prepared by Adding water and starch and formed slurry of it by Heating

14) These binder solution is then added in the Mortor pestle containing powder and excipients.

15) Blend it until the dum mass is form.

16) These dum mass is then screened by using 20 Number seive

17) Then we get the granules

18) Granules are dried in shade

19) These dried granules are passed through 30 number seive

20) After passing we get the small sized and Uniform granules

21) In these granules add magnesium Sterate

22) Mix it uniformly

23) Then the granules added in the punching Machine.

24) Tablets get compressed. And we get the Tablets.

Tablet punching:

Tablet punching is a crucial step in the process of tablet manufacturing. Tablet punching the process of compressing powders into tablets of uniform size, shape, and weight. The ces is carried out using a mechanical device called a tablet press, or tablet compression chine. The tablet press compresses the granules or mixture of Active Pharmaceutical Indient (API) and excipients to a uniform and predetermined size, shape, and weight of tablets.

Tablet Compression Machine Components:

• Die: The cavity where granules are compressed
• Punches: Upper and lower tools that come together to form the tablet
•  Compression Rolls: Large wheels that push the Punches toward the die during compression

Tablet punching machine

Principle of Tablet Compression Machine:

Tablets are formed by compressing granules using Tablet compression machines. These machines Operate based on hydraulic pressure. The pressure is Transmitted through static fluid, allowing force multiplication as needed.

The tablet compression process involves four distinct Stages:

1. Filling: Granules are transferred into position for Compression. The punch-die cavity, made of upper And lower punches, determines the volume for Granule compression.
2. Metering: Excess granules are removed, and the Required weight of granules is controlled by Adjusting the height of the lower punch in the die
3. Compression: The top and bottom punches come Together within the die to form the tablet. The Distance between the punches determines tablet Thickness and hardness.
4. Ejection: The formed tablets are ejected from dies.

Composition of Each tablet:

Evaluation Test of Tablets:

Pharmaceutical evaluation of these tablets were done by using following parameters 

1. Hardness
2. Friability
3. Weight Variation
4. Disintegration

Hardness Test:

The Monsanto tester is used to conduct this test. The tester is made up of two plungers and a barrel with a compressible spring within. When the lower plunger is contact with the tablet, no reading is obtained. By twisting the threaded bolt, the upper plunger is pressed against the spring along the radial axis until the tablet fractures. This test run on ten tablets. After then, the pressure was gradually raised until the tablet broke, and the amount of pressure needed to do so was recorded.

Hardness Test Apparatus

It was carried out utilizing a friabilater. After weighing twenty sample tablets, the tablets were placed in an automated Roche Friabilator to examine the tendency to break down. The tablets were allowed to roll at a speed of 25 rpm and fall inside the Spinning apparatus Five minutes after 100 revolutions, the tablet weight was measured. The following term was then used to determine the tablets’ friability.

Friability Test Apparatus

%Friability = (Initial weight-Final weight)/ Initial weight x 100