The Materials Used For Product Development

Published Date: 02 Nov 2017

Various materials and equipments were used to carry out the experimental work. The list of materials and equipments used are presented below:

4.1.1 MATERIALS

Table 4.1 Materials used for product development

Sr No.

Name of Material

Grade

Vendor

Function

1.

Paracetamol

IP

Pan drugs ltd

Analgesic, Antipyretic and weak anti-inflammatory

2.

Caffeine

IP

Provizer Pharma

Analgesic adjuvant

3.

Avicel pH 101

BP

H. P. Chemicals Industries

Diluent

4.

Avicel pH 102

BP

Tiwari Chemicals & Tiwari Pharma

Diluent

5.

Starch

IP

 Indo Tec Chemicals & Polymers

Diluent

6.

Dicalcium Phosphate

IP

Plus Chem

Diluent

7.

PVP K 30

IP

Tirupati Enterprise

Binder

8.

MCC Burst

---

Arihant Traders Co

Disintegrant

9.

Sodium Starch Glycolate

BP

Remedy Labs

Super Disintegrant

10.

Sodium Lauryl Sulphate

IP

Shri Krishna Enterprises

Disintegrant

11.

Ac-di-sol

IP

Tiwari Chemicals & Tiwari Pharma

Super Disintegrant

12.

Dried Starch

IP

Shubham Starch Chem Private Limited

Disintegrant

13.

Sodium Benzoate

IP

 Indo Tec Chemicals & Polymers

Preservative

14.

Tween 80

IP

Indo Tec Chemicals & Polymers

Solubilizer

15.

Colloidal Silicon Dioxide

IP

Heera Laxmi Pharma Agencies

Glidant, improves flow properties

16.

Magnesium Stearate

IP

 Hindustan Chemical Laboratory

Lubricant

17.

Distilled Water

Vehicle for binder preparation

4.1.2 EQUIPMENTS

Table 4.2 Equipments used for product development

Sr No.

Equipment

Manufactured by

1.

Weighing Balance

Mettler Toledo (MS304S)

2.

Mass Balance

Ohaus (EB series 3 & series 5)

3.

Mechanical Stirrer

Eltek Motor

4.

Rapid Mixer Granulator

Meco

5.

Bulk Density Tester

Electrolab (ETD-1020)

6.

Multi station Compression machine

Karnavati (16 station D Tooling) Rimek tablet compression machine

7.

Automatic Tablet Hardness Tester

Lab India (TH-1050S)

8.

Friability Tester

Electrolab (EF-1W)

9.

Vernier Callipers Scale (digital)

Digimatic

10.

Stability Chambers

Thermolab testing services

11.

Electromagnetic Sieve Shaker

Electrolab (EMS-8)

12.

Dissolution Testing apparatus

Electrolab (TDL-08L)

13.

Disintegration Testing apparatus

Electrolab (DE-2AL)

14.

LOD Apparatus

Sartorius (MA100)

15.

Sonicator E-1404

Life Care

16.

HPLC

UV- fluorescence Wayer’s (WE 2695)

17.

Tray dryer / Hot air oven

Harrison’s Pharma Machinery Pvt. Ltd

18.

Dehumdifier

Panacea Corporation (DEH 20TR)

19.

Retsch Fluidised bed dryer

Retsch GMVH (Germany); (TG 200)

4.2 ANALYTICAL METHOD DEVELOPMENT

Analysis is an important part in the formulation and development of any drug molecule. A suitable and validated method has to be available for the analysis of drug in the bulk, in different dosage forms and from dissolution release studies. It becomes essential to develop a simple, sensitive, accurate, precise and reproducible method for the estimation of drug samples.

For the analysis of Paracetamol and Caffeine and its assay determination, the HPLC method was used which is official in the USP.

4.3 PHYSICAL AND CHEMICAL CHARACTERIZATION OF MARKETED FORMULATION:

The reference product was tested chemically and physically to characterize it to aid formulation development.

General details of the reference product are given in Table No. 5.1. Observations of the physical and chemical characterizations are tabulated under Table No. 5.2.

4.4 PREFORMULATION STUDIES

Preformulation testing is an investigation of physical and chemical properties of a drug substance alone and when combined with excipients. It is the first step in the rationale development.

The overall objective of preformulation testing is to generate information useful to the formulator in developing a stable and bioavailable dosage form.

The use of preformulation parameters maximises the chances of formulating an acceptable, safe, efficacious and stable product, and at the same time provides the basis for optimisation of the drug product quality.

4.4.1 Physical characterisation of the API

Preformulation studies of the drug were performed to characterize it. The powder properties of Paracetamol and Caffeine were studied to evaluate their compressibility, since they had to be formulated as a tablet. Both drugs were analyzed as per in house specifications.

Table No. 4.3 Characterisation of the API (Paracetamol)

Sr. No

Test

Specification

1

Appearance

White crystals or white, crystalline powder

2

Solubility

Freely soluble in ethanol (95%) and in acetone; sparingly soluble in water; very slightly soluble in dicholoro methane and in ether

3

Identification by IR

Test A: Infra-red absorption spectrum of the sample must correspond to the spectrum obtained with Paracetamol RS or with the reference spectrum of Paracetamol.

Test B, C, D: Must comply with IP

4

4 – amino phenol

Must comply with IP

5

Loss on Drying at 105ºC (%w/w)

Not more than 0.5

6

Sulphated Ash (%w/w)

Not more than 0.1

7

Heavy metals (ppm)

Not more than 10

8

Related Substances by TLC

Must comply with IP

9

Assay on dried basis (%w/w)

Not less than 99.0 and not more than 101.0

Table No. 4.4 Characterisation of the API (Caffeine)

Sr. No

Test

Specification

1

Appearance

Silky white crystals or white, glistening needles or white crystalline powder; odorless; sublimes readily

2

Solubility

Freely soluble in chloroform and in boiling water; sparingly soluble in water and in ethanol (95%); slightly soluble in ether

3

Identification by IR

Test A: Must comply with IP

Test B,C,D: Must comply with IP

4

Appearance of solution

Must comply with IP

5

Acidity or Alkalinity

Must comply with IP

6

Related Substances by TLC

Must comply with IP

7

Heavy metals (ppm)

Not more than 20

8

Arsenic (ppm)

Not more than 3

9

Sulphated Ash(%w/w)

Not more than 0.1

10

Loss on Drying at 100ºC/ 1 hour (%w/w)

Not more than 0.5

11

Assay on dried basis (%w/w)

Not less than 98.5 and not more than 101.5

4.4.2 Determination of Bulk and Tapped density: [43]

The bulking properties of a powder are dependent on how the powder was handled and that it can be packed to have a range of bulk densities. Because the interparticulate interactions that influence the bulking properties of a powder are also the interactions that interfere with powder flow, a comparison of the bulk and tap densities can give a measure of the relative importance of these interactions in a given powder.

The bulk density is often the bulk density of the powder "as poured" or as passively filled into a measuring vessel. It is determined by measuring the volume of a known mass of powder sample that has been passed through a screen into a graduated cylinder (method I) or through a volume measuring apparatus into a cup (method II).

Method I:

4.4.3 Angle of Repose:

Procedure:

A funnel was kept vertically on a stand at a specified height above a paper placed on a horizontal surface. The end of the funnel was closed and 10 gm of sample powder was introduced in it. The closed end was opened to release the powder onto the paper to form a smooth conical heap. The height of the heap was measured using a scale. The circumference of the heap was marked and its diameter was measured at four points. The average diameter was calculated and radius was found out from it.

The angle of repose was calculated using following formula:

where; h = height of the heap

r = radius of the circumference of the heap

Table: 4.5 Flow properties of powder according to its angle of repose:

Flow property

Angle of repose (degrees)

Excellent

25 – 30

Good

31 – 35

Fair – aid not needed

36 – 40

Passable – may hang up

41 – 45

Poor – must agitate, vibrate

46 – 55

Very poor

56 – 65

Very, very poor

> 66

4.4.4 Compressibility Index and Hausner’s ratio:

The Compressibility Index and Hausner Ratio are measures of the propensity of a powder to be compressed. They are measures of the relative importance of interparticulate interactions. In a free flowing powder, such interactions are generally less significant, and the bulk and tapped densities will be closer in value. For poorer flowing materials, there are greater interparticle interactions, and a greater difference between the bulk and tapped densities will be observed. These differences are reflected in the Compressibility Index (Carr’s Index) and Hausner Ratio.

Table 4.6 Scale of Flowability by compressibility index

C.I range

Category

5-10

Excellent

11-15

Good

16-20

Fair

21-25

Passable

26-31

Poor

32-37

Very Poor

>38

Very, Very poor

Table 4.7 Scale of Flowability by Hausner’s ratio

Limits of H.R

Category

1.00 - 1.11

Excellent

1.12 - 1.18

Good

1.19 – 1.25

Fair

1.26 – 1.34

Passable

1.35 – 1.45

Poor

1.46 – 1.59

Very Poor

>1.60

Very, Very Poor

4.4.5 Loss on Drying:

L.O.D of a compound measures the % content of water and volatile substances present in it. This was performed by placing 1g of Paracetamol and Caffeine individually at 105°C for 10 minutes in Sartorius (MA100) infrared moisture analyzer.

4.4.6 Particle size distribution :

Procedure:

Sieves of different sizes were fitted in the platform of a sieve shaker in such a way that coarse sieve was placed on top corresponding to finer sieves. 50 gm of Paracetamol was placed on top sieve and the shaker was started. After ten minutes the machine was stopped and weight of powder retained on each sieve was found. Percentage retention on each sieve was calculated by following equation:

Amount of powder retained (gm)

% powder retained = ----------------------------------------- X 100

Total amount of powder (gm)

4.4.7 Drug Substance – Excipient Compatibility Studies

For the systematic development of an immediate release tablet formulation, the pharmaceutical development was initiated with drug – excipient study. Compatibility studies were conducted to investigate and predict physicochemical interaction between drug substance and excipients and thereafter to select suitable i.e chemically compatible excipients.

The following excipients were selected for the study:

Avicel pH 101

Avicel pH 102

Starch

Dicalcium Phosphate

PVP K 30

MCC Burst

Sodium starch glycolate

Sodium Lauryl Sulphate

Ac-di-sol

Sodium Benzoate

The blends of Paracetamol, Caffeine and commonly used excipients were subjected to 3 conditions, i.e. 25ºC/60%RH, 30ºC/65%RH and 40ºC/75%RH to evaluate the compatibility. Proportions of Paracetamol, Caffeine and the excipients were used as shown in Table No.4.7. These mixtures were kept in open glass vials. Physical observation was done initially, after 15 days and after 30 days.

4.4.7.1 Physical observation

The samples were observed physically for any change in the color, lump formation or changes in the flow at 15 days and 30 days.

Table No. 4.8 Proportions of Paracetamol, Caffeine and the excipients used

Sr No.

Sample

Ratio

1.

Paracetamol alone

---

2.

Caffeine alone

---

3.

Paracetamol + Caffeine

1:1

4.

Paracetamol + Caffeine + Avicel pH 101

1:1:1

5.

Paracetamol + Caffeine + Avicel pH 102

1:1:1

6.

Paracetamol + Caffeine + Starch

1:1:1

7.

Paracetamol + Caffeine + Dicalcium Phosphate

1:1:1

8.

Paracetamol + Caffeine + PVP K 30

1:1:1

9.

Paracetamol + Caffeine + MCC Burst

1:1:1

10.

Paracetamol + Caffeine + Sodium starch glycolate

1:1:1

11.

Paracetamol + Caffeine + SLS

1:1:1

12.

Paracetamol + Caffeine + Acdisol

1:1:1

Paracetamol + Caffeine + Sodium Benzoate

1:1:1

4.5 FORMULATION AND DEVELOPMENT

4.5.1 Preliminary trials by Wet Granulation Technique

Core tablets of Paracetamol and Caffeine were prepared by the wet granulation technique.

General steps involved in Manufacturing Procedure

Manufacturing Process

Dispensing

Checked weight of all the ingredients as per the formula and recorded the same in the Lab notebook.

2. Sifting

Sifted the dispensed quantities of Paracetamol and Caffeine individually through sieve # 40 ASTM. After this the dispensed quantities of diluents were passed through sieve # 40 and # 60 respectively. The remaining materials were ie. disintegrants, super disintegrants, lubricants and glidants were passed through sieve # 60 and MCC through sieve # 40 on a vibratory sifter.

3. Preparation of Binder Solution

Starch paste (used as the binder) was prepared by making a slurry of the dispensed quantity of starch in half the amount of water required to make the paste. The remaining half quantity of water was taken in a beaker and placed on a hot plate for heating. The sifted quantity of preservative was dissolved in a little amount of water separately and filtered through a nylon cloth. Tween 80 was added to the boiling water placed on the hot plate after which the above filtered preservative solution was added to it. To this boiling solution, the previously made starch slurry was added and rapidly stirred with the help of a stirrer in order to avoid lump formation and get a thick paste of desired consistency.

4. Preparation of PVP K-30 binder solution

Took the weighed quantity of PVP K-30 in a beaker and to this was added appropriate amount of distilled water. The resulting mixture was stirred for around 1.5 hours using a mechanical stirrer in order to solubilise it and get a clear solution. After obtaining a clear solution, it was kept aside for 30 minutes and filtered using a nylon cloth.

5. Wet Granulation

5.1 Dry Mixing

The dispensed and sifted quantities of Paracetamol, Caffeine and diluents were blended together in a polybag for about 5 minutes and the prepared blend was then spread in a tray in a dehumidified area for granulation.

5.2 Adjustment of quantity of binder solution:

Added a little of the binder solution to the above blend after dry mixing. Quantity of binder solution was adjusted by checking whether the binding mass was properly formed and is not breaking in more than 3 parts.

5.3 Binder addition and Granulation and Drying

Added the above prepared binder solution from step 4 into the dry mix and granules were prepared of the required consistency. This wet mass of granules was then introduced into the bowl of a fluidised bed dryer in order to bring about simultaneous size reduction of the prepared granules and to dry them. Drying was done to get LOD in the range of 3 – 4% w/w. After getting the satisfactory granular mass, the granules were unloaded from the FBD and the final LOD was checked and the Outlet temperature and yield of dried granules were noted.

6. Sizing of Granules

Passed the dried granules from the above step through ASTM sieve # 16 and collected the granules into a clean double polybag.

Recorded the yield of the sized granules and performed particle size distribution test.

7. Blending and Lubrication:

The sized granules were then mixed with the weighed and sifted quantities of disintegrant, super disintegrant, glidants and lubricants in a poly bag for 5 - 7 minutes. This final lubricated blend, ready for compression was then evaluated for pre compression parameters such as BD, TD, angle of repose, Carr’s Index and Hausner Ratio.

8. Compression:

Loaded the lubricated granules into the hopper and compressed the blend using 5.8 mm, Round, Standard Concave punches.

4.5.2 Composition of Batch No. SBS 01 and SBS 02 (Binder Optimisation)

Objective: Trials were taken in order to select a suitable binder (Starch or PVP K-30) that will provide desired strength to the tablets during compression. MCC 102 was used as a disintegrant, whereas Ac-di-sol was used as the superdisintegrant.

Table No. 4.9 Composition of Batch No. SBS 01 and SBS 02

Sr no.

Ingredients

Mg per tab

SBS 01

Mg per tab

SBS 02

1.

Intra granular

Paracetamol

325

325

2.

Caffeine

50

50

3.

Starch

49.616

49.616

4.

Binder solution

Starch (paste)

15

---

5.

PVP K 30

---

15

6.

Tween 80

0.06

0.06

7.

Sodium benzoate

10

10

8.

Distilled water

Qs

Qs

9.

Pre Lubrication

Ac-di-sol

25

25

10.

MCC 102

21.324

21.324

11.

Lubrication

Aerosil

2

2

12.

Magnesium stearate

2

2

Procedure:

Checked weight of all the ingredients as per the formula, dispensed and sifted the materials used in formulation of tablets.

Starch paste (used as the binder) was prepared as per the procedure cited above and was used for granulating Batch No. SBS 01.

Alternatively, PVP K 30 solution (used as the binder) was used for granulating Batch No. SBS 02.

Prepared granules were dried in an FBD and were then passed through BSS sieve # 16 and collected into a clean double polybag.

The sized granules were then mixed with the weighed and sifted quantities of disintegrant, super disintegrant, glidants and lubricants in a poly bag for 5 - 7 minutes. This final lubricated blend, ready for compression was then evaluated for pre compression parameters such as BD, TD, angle of repose, Carr’s Index and Hausner Ratio.

The lubricated blend was compressed 5.8 mm, Round, Standard Concave punches.

4.5.3 Composition of Batch No. SBS 03 (Binder Optimisation)

Objective: A trial was taken in order to optimise the binder used for tablet granulation and compression. A combination of starch and PVP K 30 was used as the binder in order to provide desired strength to the tablets. MCC 102 was used as a disintegrant, whereas Ac-di-sol was used as the superdisintegrant.

Table No. 4.10 Composition of Batch No. SBS 03

Sr no.

Ingredients

Mg per tab

SBS 03

1.

Intra granular

Paracetamol

325

2.

Caffeine

50

3.

Starch

42.616

4.

Binder solution

Starch

7

5.

PVP K 30

15

6.

Tween 80

0.06

7.

Sodium benzoate

10

8.

Distilled water

qs

9.

Pre Lubrication

Ac-di-sol

25

10.

MCC 102

21.324

11.

Lubrication

Aerosil

2

12.

Magnesium stearate

2

Lubricated granules were prepared as per the general manufacturing procedure detailed above and the blend was checked for pre compression parameters such as BD, TD, angle of repose, Carr’s Index and Hausner Ratio.

The final blend was then compressed into tablets using a 5.8 mm, round, standard concave punch, after which evaluation of compressed tablets was done.

4.5.4 Composition of Batch No. SBS 04 and SBS 05 (Super Disintegrant Optimisation)

Objective: Trials were taken using a combination of super disintegrants in different concentrations, so as to achieve a desired Disintegration Time. SSG was used along with Ac-Di-Sol in two different concentrations ie. 2% and 4% w/w.

Table No. 4.11 Composition of Batch No. SBS 04 and SBS 05

Sr no.

Ingredients

Mg per tab

SBS 04

Mg per tab

SBS 05

1.

Intra granular

Paracetamol

325

325

2.

Caffeine

50

50

3.

Starch

32.616

22.616

4..

Binder solution

Starch (paste)

7

7

5.

PVP K 30

15

15

6.

Tween 80

0.06

0.06

7.

Sodium benzoate

10

10

8.

Distilled water

Qs

Qs

9.

Ac-di-sol

25

25

10.

Pre Lubrication

Sodium Starch Glycolate

10

20

11.

MCC 102

30.824

30.824

12.

Lubrication

Aerosil

2.5

2.5

13.

Magnesium stearate

2

2

Lubricated granules were prepared as per the general manufacturing procedure detailed above and the blend was checked for pre compression parameters such as BD, TD, angle of repose, Carr’s Index and Hausner Ratio.

The final blend was then compressed into tablets using a 5.8 mm, round, standard concave punch, after which evaluation of compressed tablets was done.

4.5.5 Composition of Batch No. SBS 06 and SBS 07 (Diluent Optimisation; Addition of Sodium Lauryl Sulphate as a surfactant)

Objective: Trials were taken using a combination of diluents ie. Starch along with DCP and Starch along with MCC 101. The diluent was changed so as to determine whether there was any difference in the drug release studies. Also SLS was added in a 1% w/w concentration as a surfactant in order to promote drug release.

Table No. 4.12 Composition of Batch No. SBS 06 and SBS 07

Sr no.

Ingredients

Mg per tab

SBS 06

Mg per tab

SBS 07

1.

Intra granular

Paracetamol

325

325

2.

Caffeine

50

50

3.

Starch

10

10

4.

DCP

12.616

---

5.

MCC 101

---

12.616

6.

Binder solution

Starch (paste)

7

7

7.

PVP K 30

15

15

8.

Tween 80

0.06

0.06

9.

Sodium benzoate

10

10

10.

Distilled water

Qs

Qs

11.

Ac-di-sol

20

20

12.

Pre Lubrication

Sodium Starch Glycolate

20

20

13.

SLS

5

5

14.

MCC 102

30.824

30.824

15.

Lubrication

Aerosil

2.5

2.5

16.

Magnesium stearate

2

2

4.5.6 Composition of Batch No. SBS 08 and SBS 09 (Use of Co-processed super disintegrants)

Objective: Trials were taken using co-processed super disintegrants (SSG and Ac-di-sol) in different ratios (3:1 and 2:1) to evaluate its effectiveness on tablet disintegration and dissolution properties.

Table No. 4.13 Composition of Batch No. SBS 08 and SBS 09

Sr no.

Ingredients

Mg per tab

SBS 08

Mg per tab

SBS 09

1.

Intra granular

Paracetamol

325

325

2.

Caffeine

50

50

5.

MCC 101

25.616

33.616

6.

Binder solution

Starch (paste)

7

7

7.

PVP K 30

15

15

8.

Tween 80

0.06

0.06

9.

Sodium benzoate

10

10

10.

Distilled water

Qs

Qs

11.

Ac-di-sol

24

16

12.

Pre Lubrication

Sodium Starch Glycolate

8

8

13.

IPA

Qs

Qs

14.

MCC 102

30.824

30.824

15.

Lubrication

Aerosil

2.5

2.5

16.

Magnesium stearate

2

2

4.5.7 Composition of Batch No. SBS 10, SBS 11 and SBS 12 (To study the effect of different grades of MCC as an intra granular and extra granular excipient)

Objective: Trials were taken using MCC 101 and MCC 102 as the intra granular diluents. SBS 10 incorporated only MCC 101, whereas SBS 11 and SBS 12 used MCC 102 as the intragranular diluent. Also at the same time, MCC 102 was used as a disintegrant in SBS 10 and 11; whereas MCC burst (6%w/w) was used as the disintegrant in trial 12; Ac-di-sol being the common super disintegrant used for all trials.

Table No. 4.14 Composition of Batch No. SBS 10, SBS 11 and SBS 12

Sr no.

Ingredients

Mg per tab SBS 10

Mg per tab SBS 11

Mg per tab SBS 12

1.

Intra granular

Paracetamol

325

325

325

2.

Caffeine

50

50

50

3.

MCC 101

42.44

---

---

4.

MCC 102

---

42.44

42.44

5.

Binder solution

Starch (paste)

7

7

7

6.

PVP K 30

15

15

15

7.

Tween 80

0.06

0.06

0.06

8.

Sodium benzoate

1

1

1

9.

Distilled water

Qs

Qs

Qs

10.

Ac-di-sol

25

25

25

11.

Pre Lubrication

MCC 102

30

30

---

12.

MCC Burst

---

---

30

13.

Lubrication

Aerosil

2.5

2.5

2.5

14.

Magnesium stearate

2

2

2

4.5.8 Composition of Batch No. SBS 13 (To study the effect of increased concentration of MCC Burst on disintegration time and Dissolution profile of the tablet)

Objective: A trial was taken using MCC Burst in a concentration of 7.8% w/w as compared to the trial taken in SBS 12. MCC 102 was used as the intra granular diluent and Ac-di-sol as the extragranular super disintegrant.

Table No. 4.15 Composition of Batch No. SBS 13

Sr no.

Ingredients

Mg per tab

SBS 13

1.

Intra granular

Paracetamol

325

2.

Caffeine

50

3.

MCC 102

33.44

4.

Binder solution

Starch

7

5.

PVP K 30

15

6.

Tween 80

0.06

7.

Sodium benzoate

1

8.

Distilled water

Qs

9.

Pre Lubrication

MCC Burst

39

10.

Ac-di-sol

25

11.

Lubrication

Aerosil

2.5

12.

Magnesium stearate

2

4.5.2 Pre-Compression Parameters[43]

The following parameters were determined:

Bulk density:

It is the ratio of the mass of an untapped powder sample and its volume including the contribution of the interparticulate void volume. Hence it depends upon both the density of the powder particles and the spatial arrangement of the particles in the powder bed. It is expressed in grams per ml (g/mL). The bulking properties of a powder are dependent upon the preparation, treatment, and storage of the sample, i.e., how it was handled. Thus, the bulk density of a powder is often very difficult to measure with good reproducibility and, in reporting the results, it is essential to specify how the determination was made.

Method: Measurement in a graduated cylinder

Pass a quantity of material sufficient to complete the test through a sieve with aperture greater than or equal to 1.0 mm, if necessary, to break up agglomerates that may have formed during storage; this must be done gently to avoid changing the nature of the material. Into a dry graduated 250 mL cylinder (readable to 2 mL) introduce, without compacting, approximately 100 g of the test sample, M, weighed with 0.1% accuracy. Carefully level the powder without compacting, if necessary, and read the unsettled apparent volume (V0) to the nearest graduated unit. Calculate the bulk density in g/mL by the formula M/ V0. Generally replicate determinations are desirable for the determination of this property.

If the powder density is too low or too high, such that the test sample has an untapped apparent volume of either more than 250 mL or less than 150 mL, it is not possible to use 100g of the powder sample. Therefore, a different amount of powder has to be selected as the test sample, such that its untapped apparent volume is 150mL to 250mL (apparent volume greater than or equal to 60% of the total volume of the cylinder); the weight of the test sample is specified in the expression of the results.

For the test sample with apparent volume between 50 mL and 100 mL, a 100 mL cylinder readable to 1 mL can be used; the volume of the cylinder is specified in the expression of results.

The equation for determining the bulk density is,

Tapped density:

It is an increased bulk density attained after mechanically tapping a container containing the powder sample. It is obtained by mechanically tapping a graduated measuring cylinder containing a powder sample. After observing the initial powder volume or weight, the measuring cylinder is mechanically tapped, and volume or weight readings are taken until little further volume or weight change is observed. The mechanical tapping is achieved by raising the cylinder and allowing it to drop under its own weight a specified distance.

APPARATUS: A 250 mL graduated cylinder (readable to 2 mL with a mass of 220 ± 44g)

A settling apparatus capable of producing, in 1 minute, either nominally 250 ± 15 taps from a height of 3 ±0.2 mm, or nominally 300 ± 15 taps from a height of 14 ± 2 mm.

PROCEDURE: Secure the cylinder in the holder. Carry out 10, 500, and 1250 taps on the same powder sample and read the corresponding volumes V10, V500, V1250 to the nearest graduated unit. If the difference between V500 and V1250 is less than 2 mL, V1250 is the tapped volume. If the difference between V500 and V1250 exceeds 2 mL, repeat in increments such as 1250 taps, until the difference between succeeding measurements is less than 2 mL. Calculate the tapped density (g/mL) using the formula M/Vf in which Vf is the final tapped volume. Generally, replicate determinations are desirable for the determination of this property. If it is not possible to use a 100 g test sample, use a reduced amount and a suitable 100 mL graduated cylinder weighing 130 ± 16 g and mounted on a holder weighing 240 ± 12g. Calculate the tapped density in g/mL, by the formula:

Measure of powder compressibility:

The compressibility index of the granules/powder was determined by Carr’s index. The Carr’s index is determined from the tapped density and poured density (bulk density) as per the formula given below,

Hausner’s ratio is determined from the ratio of tapped density to bulk density using formula given below.

Angle of Repose:

The angle of repose of the blend was calculated using following formula:

where; h = height of the heap

r = radius of the circumference of the heap

Table No. 4.16 Compression Parameters

Sr. No

Parameters

Observations

1.

Machine

Karnavati tablet compression machine

2.

Tooling

D

3.

Punch Shape

Round Standard Concave Punch

4.

Punch Dimensions

5.8 mm

5.

No. of Punches

1

6.

Speed

20 rpm

4.5.3 Evaluation of Tablets

4.5.3.1 Appearance

Twenty tablets of each formulation were taken to check any discoloration or surface roughness in the tablet formulation.

4.5.3.2 Weight Variation Test

Weight variation of tablets was calculated by weighing 20 tablets individually and determining the average weight. The tablets meet the test if not more than two of the individual weights deviate from the percentage limits.

Table No. 4.17 Weight variation Tolerance for Uncoated Tablets

Sr. No

Average weight of Tablets (mg)

Maximum % difference allowed

1.

80 or less

10

2.

More than 80 but less than 250

7.5

3.

More than 250

5

4.5.3.3 Hardness

The hardness of five tablets was determined using the Automatic Tablet Hardness Tester and the average values were calculated.

4.5.3.4 Thickness and Diameter

The Thickness and Diameter of the tablets was determined by using Automatic Tablet Tester. Twenty tablets were used, and average values were calculated.

4.5.3.5 Friability

It is intended to determine the loss of mass under defined conditions. The friability of the uncoated tablets was determined using an Electrolab Friabilator. This device subjects a number of tablets to the combined effects of abrasion and shock by utilizing a plastic chamber that revolves at 25 rpm dropping the tablets at a distance of six inches with each operation for 100 revolutions. The tablets are then dedusted and reweighed. Tablets that loose less than 1% of the weight of the loss of mass and it is calculated as a percentage of the initial mass. The extent of friability was calculated using following formula,

The values for both Hardness & Friability can together indicate the mechanical strength of the tablet.

4.5.3.6 Disintegration Time

The disintegration time of 6 tablets was measured using USP Disintegration apparatus at 37.5ºC.

4.5.3.7 Assay[39]

USP Reference standards- USP Acetaminophen RS

USP Caffeine RS

Mobile phase – Suitable mixture of water, methanol, and glacial acetic acid (69:28:3) was prepared as a mobile phase.

Solvent mixture- Prepared a mixture using HPLC grades of methanol and glacial acetic acid in a ratio of 95:5

Standard stock solution- 62.5 mg and 9.615 mg of accurately weighed quantities of USP Acetaminophen RS and USP Caffeine RS respectively were dissolved in Solvent mixture to obtain a solution having known concentration of about 0.25 mg of USP Acetaminophen RS per mL and 0.25J mg of USP Caffeine RS per mL, J (i.e. 50/325) being the ratio of the labelled amount, in mg, of caffeine to the labelled amount in mg, of acetaminophen per tablet.

Standard preparation- 25 mL of the Standard stock solution was transferred to a 50 mL volumetric flask, diluted with the solvent mixture upto 50 mL, and mixed. This solution contained 0.125 mg of USP Acetaminophen RS and 0.19 mg of USP Caffeine RS per mL.

Assay preparation- 20 tablets containing Acetaminophen and Caffeine were weighed and powdered together. A quantity equivalent to 250 mg of acetaminophen (384.6 mg) was accurately weighed from this powdered triturate and transferred to a 100 mL volumetric flask. About 75 mL of the solvent mixture was added to this weighed quantity after which the flask was placed on an orbital shaker for about 30 minutes. Further dilutions were made with the solvent mixture and the volume was made upto 100 mL. 2 mL of this solution was transferred to a 50 mL volumetric flask and volume was made up with the solvent mixture.

Chromatographic system- The liquid chromatograph was equipped with a 275 nm detector and a 4.6 mm*10 cm column that contained 5µm packing L1, and is maintained at 45±1°. The flow rate was about 2 mL per minute. The standard preparation was chromatographed and responses were recorded as directed for the procedure: the tailing factor for each analyte peak was not more than 1.2 and the relative standard deviation for replicate injections was not more than 2.0%

Procedure- Equal volumes (about 20 µL) of the standard preparation and the Assay preparation were injected separately into a chromatograph. Chromatograms were recorded, and responses for the major peaks were measured. The retention times were about 1.078 min for Acetaminophen and 1.825 min for Caffeine.

% w/w of Acetaminophen and Caffeine in the portion of tablets taken were calculated as under:

Area (sample)/Area (std) * Conc. (std)/ Conc. (sample) * % Purity

4.5.3.8 In-vitro drug release studies[39]

Medium: Water; 900 mL

Apparatus 2: 100 rpm

Time: 5, 10, 15, 20, 30 minutes

Mobile phase, solvent mixture, standard stock solution, and chromatographic system: were prepared as directed in the Assay.

Standard solution - 25 mL of Standard stock solution was prepared and transferred to a 50 mL volumetric flask. To this solution was added 20 mL of water and mixed together and allowed to stand for about 30 seconds. The volume was then made upto 50 mL with the solvent mixture, mixed and kept aside.

Test solution- Transferred 10 mL of the filtered portion of an aliquot from the solution under test to a 50 mL volumetric flask. To this was added 20 ml of the solvent mixture, mixed, and allowed to stand for 30 seconds. The volume was then made upto 50 mL with the solvent mixture and mixed well for use.

Procedure: Aliquots were withdrawn from the dissolution apparatus at the given time intervals and test solutions were prepared. This test solution was then filtered using a syringe filter and transferred to the vials and labelled accordingly. The vials containing the test and standard solutions were then transferred to the HPLC auto sampler and the chromatograms were recorded, and responses for the peaks were measured. The amount of drug present in the tablet was calculated using the following formula:

Area (sample)/Area (std) * Conc. (std)/ Conc. (sample) * % Purity

4.6 STABILITY STUDY PROTOCOL

Developed products were kept for stability studies at 40ºC/75%RH in PVC Aluminium blister pack for a 2 month period to study the physical and chemical changes.

Table No. 4.18 Stability study protocol for Paracetamol and Caffeine tablets

Product Name

Paracetamol and Caffeine Tablets

Label Claim

Each uncoated tablet contains

Paracetamol IP…..325 mg

Caffeine IP…..50 mg

Batch No.

SBS 12 and SBS 13

Stability term

2 month

Pack Detail

PVC Aluminium blister

Reason for Stability

To evaluate stability of prepared batch of tablets

Tests to be performed:

Determination of Physical Parameters

Assay (using HPLC)

In-vitro drug release studies (using HPLC)

Results of stability studies are depicted in Chapter 6. (Results and Discussions)