Lamotrigine Tablet 25mg 50mg and 100mg Testing By UV and HPLC Method

Testing Lamotrigine tablets (100mg) using UV (Ultraviolet) spectroscopy and HPLC (High-Performance Liquid Chromatography) are common methods Lamotrigine Tablet 25mg 50mg and 100mg Testing By UV and HPLC Method in pharmaceutical analysis to determine the concentration and purity of the active pharmaceutical ingredient (API) in the formulation. Here’s a brief overview of how you can perform these tests:


To describes the procedure for analysis at in-process and finished stage of Lamotrigine Tablet 25mg 50mg and 100mg Testing By UV and HPLC Method.


This SAP gives detailed outline for the finished product analysis of Lamotrigine Tablet 25mg 50mg and 100mg Testing By UV and HPLC Method and will cover In process testing activities on physical, chemical & instrumental basis.


QC Analyst is responsible for physical / chemical testing and preparing standard analytical procedure.
It is the responsibility of QC Manager to assist and ensure Testing Procedure as per SAP and to make certain that this SAP is followed in its entirety, reviewed regularly and revised as necessary.


USP 44, NF 39


  • UV Spectrophotometer
  • HPLC
  • Dissolution apparatus
  • Friability apparatus
  • Hardness apparatus
  • Disintegration Tester
  • Vernier Caliper
  • Analytical Balance
  • Moisture analyzer
  • Mortar and pestle
  • Spatula
  • Filter Paper
  • Magnetic Stirrer & Hot Plate
  • Sonicator
  • Vacuum Pump
  • Glassware
  • Distilled water
  • 0.1 N Hydrochloric acid
  • Ammonium Acetate
  • Glacial Acetic Acid
  • Methanol


white color powder.
Procedure:   Take 2.0 g of the test sample in a watch glass and observe visually with black background. Check the appearance of color, nature and any visible foreign particles.
The spectrum of the sample preparation corresponds to spectrum of the standard preparation as obtained in the assay.
The retention time of the lamotrigine peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
Assay: (Limit: 90%-110%)

Testing Procedure By HPLC:

Buffer: 0.8 g/L of ammonium acetate. Adjust with glacial acetic acid to a pH of 4.5.
Mobile phase: Methanol and Buffer (60:40)
Standard solution: 0.05 mg/mL of USP Lamotrigine RS in Mobile phase
Sample solution: Transfer an amount equivalent to 100 mg of lamotrigine from a portion of crushed Tablets (NLT 20)to a suitable volumetric flask to obtain a nominal concentration of lamotrigine of 1.0 mg/mL. Dissolve in70% of the flask volume of Mobile phase by sonicating for20 min. Dilute with Mobile phase to volume. Centrifuge the solution. Quantitatively dilute a suitable volume of centrifugate with Mobile phase to obtain a nominal concentration of 0.05 mg/mL of lamotrigine.
Chromatographic system
(See Chromatography (621), System Suitability.)
Mode: LC
Detector: UV 210 nm
Column: 4.6-mm x 15-cm; 5-um packing L1
Flow rate: 1 mL/min
Injection size: 10 uL
System suitability
Sample: Standard solution
Suitability requirements
Tailing factor: NMT 2.0 for lamotrigine
Relative standard deviation: NMT 2.0% for lamotrigine
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of lamotrigine (C9H7Cl2N5) in the portion of Tablets taken:
Result =(Ru/Rs) x (Cs/Cu) x 100
Ru=peak response from the Sample solution
Rs=peak response from the Standard solution
Cs=concentration of USP Lamotrigine RS in the Standard solution(mg/mL)
Cu=nominal concentration of lamotrigine in the Sample solution(mg/mL)
Limit:  Lamotrigine : 90%-110%of the labeled amount

Alternate Method By UV Spectrophotometer

Standard Solution:
Take 50 mg of Lamotrigine WS dissolved in 10 mL methanol and make up the volume to 100mL with 0.1N HCl. Shake, and sonicate for 5 minutes to facilitate dissolution.
Take 5 mL from standard stock solution and make up the volume to 50 mL with 0.1N HCl.
Sample solution: 
Take 5gram of sample grind them to fine powder. Take compression weight of finally grinded powder and dissolved in 10 mL methanol and make up the volume to100 with 0.1N HCl. Shake by mechanical mean for 10 minutes to disperse and allow any insoluble matter to settle.
Take 5 mL from standard stock solution and make up the volume to 50 mL with 0.1N HCl.
Pass a portion of the sample stock solution through a suitable filter of 0.45um pore size.
Take reading at UV spectrophotometer at 267 nm using 0.1N HCl as blank.
Sample Absorbance x Standard Concentration x Ave. Weight of Tablet x Potency
Standard Absorbance x Sample Concentration x Label Claim
Limit:  Lamotrigine: 90%-110%of the labeled amount

Uniformity of Dosage Units: (By Weight Variation)

Weigh 20 tablets individually and calculate the average weight as:
Average weight = (Weight Of 20 Tablets)/20
Weigh all these tablets individually and mark among these weights maximum (WMax) & minimum (WMin) weight tablets. Calculate the maximum and minimum variation in percent as:
Maximum% age variation =((WMax) – (WAvg.))/WAvg×100
Minimum % age variation ((WMin) – (WAvg.))/WAvg×100

Hardness Test & Dimensions:

Perform the hardness test on 10 tablets and take the average. Power on the instrument and regulate zero adjustment and preset the ‘’HARDNESS’’ and “Thickness” mode. Place the tablet on the test plate, begin testing and read the hardness thickness and diameter. Clean the shattered tablet and print out test results, perform the test on 10 tablets and take the average.
Hardness Standard Limit: …….
Thickness Standard Limit:……..
Length/Diameter Standard Limit:……

Friability Test:

For tablets with a unit mass equal to or less than 650 mg, take a sample of whole tablets corresponding to 6.5 g. For tablets with a unit mass of more than 650 mg, take a sample of 10 whole tablets. The tablets should be carefully dedusted prior to testing. Accurately weigh the tablet sample, and place the tablets in the drum. Rotate the drum 100 times, and remove the tablets. Remove any loose dust from the tablets as before, and accurately weigh. Generally, the test is run once. If obviously cracked, cleaved, or broken tablets are present in the tablet sample after tumbling, the sample fails the test. If the results are doubtful or if the weight loss is greater than the targeted value, the test should be repeated twice and the mean of the three tests determined. A maximum mean weight loss from the three samples of not more than 1.0% is considered acceptable for most products.
% FRIABILITY=    W1-W2   x 100/W1

Disintegration Test:

Place the beaker filled with water into the beaker stand inside the bath and. Switch on the instrument, set the temperature at 37ºC± 2º C and wait till the temperature of the beaker reaches to the 37ºC± 2º C. Engage the basket on basket hook put the tablets in 6 tubes individually and place the discs then start the oscillations and timer. Note the disintegration time of all the six tablets.
Note the Disintegration time of 1st tablet to the last tablet.
Disintegration Time: NMT 15 minutes at 370C ± 20C
Acceptance criteria of disintegration for tablets:
If 1 or 2 tablets fail to disintegrate completely repeat the test on 12 additional tablets, not less than 16 of the totals of 18 tablets tested disintegrate completely.

Leak Test:

Take 06 blisters of tablet 03 filled and 03 empty. Dip these blisters in the bowl of leak test apparatus containing colored water. Create vacuum 250 mmHg and hold for one minute. Release vacuum and check the penetration of water inside the blisters. All blisters should be free of water.

Dissolution Test:

USP Apparatus: USP Apparatus II Peddle
Medium: 0.1 N hydrochloric acid; 900 mL
Speed: 50 rpm
Time: 30 Minute
Medium Temperature: 37º ± 0.5º
Recommended Sampling Time: Lamotrigine: 30 Minute
Diluent: Dissolution medium
Determine the amount of lamotrigine (C9H7Cl2N5) dissolved by using one of the following methods.

Spectrometric method

Standard stock solution: 0.15 mg/mL of USP Lamotrigine RS in Medium prepared as follows.
Dissolve a suitable quantity in 5% of the flask volume of methanol, then dilute with Medium to volume.
Standard solution: Dilute the Standard stock solution with Medium to obtain a final concentration of 0.028 mg/mL.
Sample solution: Pass a portion of the solution under test through a suitablefilterof0.45um pore size. Dilute with Medium according to Table 7.
Calculate the percentage of the labeled amount of Lamotrigine (C9H7Cl2N5) dissolved:
Result = (Au/As) x (Cs/L) x D x Vx 100
Au = absorbance of the Sample solution
As = absorbance of the Standard solution
Cs = concentration of the Standard solution(mg/mL)
L = label claim (mg/Tablet)
D = dilutionfactor of the Sample solution
V = volume of Medium, 900 mL
Instrumental Conditions
Mode: UV
Analytical wavelength: UV 267 nm
Blank: Medium
Sample Absorbance       x      Standard Concentration      x      Potency
Standard Absorbance    x     Sample Concentration
The amount of drug dissolve in solution for each tablet is not less Than 80% Q of the amount stated on the label for Lamotrigine at 30 minute.

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