Test Method for Acyclovir Tablets

Acyclovir is used to treat infections caused by certain types of viruses. It treats cold sores around the mouth (caused by herpes simplex), shingles (caused by herpes zoster), and chickenpox. This medication is also used to treat outbreaks of genital herpes.

Visually examine the representative number of tablets for colour, shape, markings and the presence of foreign matter 

The retention time of the major peaks in the chromatogram of sample preparation should corresponds to that of the major peaks in the chromatogram of the standard preparation, as obtained in the assay. 

Average Weight: 
Weigh 20 tablets & calculate the average weight using calibrated weighing balance. 

Weight Variation: 
Weigh 20 tablets individually & find out the average weight. 

Determine the thickness of 10 tablets individually using Vernier caliper. 

Determine the hardness of 10 tablets individually using hardness tester. 

Weigh tablets weight equivalent to 6.5 g & put the tablets in the friability test apparatus & operate the instrument for 4 minutes. (4×25 revolutions = 100 revolutions). Reweigh the tablets after the test. 
Initial weight of tablets : ________ W1 g 
Final weight of tablets : _________ W2 g 
Loss of weight : ______________ (W1 – W2) g 

Place 1 tablet in each of the 6 tubes of the basket & cover with disc. Operate the apparatus using water, maintained at 37 ± 2°C, as the immersion fluid. At the end of the specified time, lift the basket from the fluid & observe the dosage units. All of the dosage unit disintegrate completely. 

Note: Disintegration is considered to be completed when no residues except fragments of undissolved tablet remains on the screen of the test apparatus. 

Dissolution Condition: 
Medium 0.1 N hydrochloric acid ; 900 mL. 
Apparatus II ( Paddles ) 
Speed 50 RPM 
Time 45 minutes. 
Temperature 37°C ± 0.5°C 

Preparation of Medium: 
Dilute 51mL of Conc. HCl in 6L of water. Mix well. 

Standard Solution: 
Transfer 45mg Acyclovir secondary reference standard to 100 mL volumetric flask, add 70 mL dissolution medium, sonicate to dissolve and make up to volume with dissolution medium. Dilute 2 mL of resulting solution to 50mL with dissolution media. 

Sample Solution: 
Place 900 mL of dissolution medium maintained at 37 ± 0.5°C in 6 dissolution vessels separately & fix in the tablet dissolution bath maintained at 37 ± 0.5°C. fix the paddle to the shaft & bring it into the position. Place 1 tablet each into 6 dissolution vessels. Operate the instrument at 50 RPM for 45 minutes. At the end of 45 minutes, Withdraw from each of the vessels about 10mL, and Dilute 2 mL of this solution in to 50 mL of Dissolution medium. Measure the absorbance of the standard and sample at 254nm. 

% Dissolution of the Acyclovir = 

    At = Area of Sample Solution
    As = Average Area of standard solution
    Ws = Weight of standard
    V = Volume of Medium
    L = Label Claim
    P = Potency of Standard

Chromatographic Conditions: 
Column 250 mm × 4.6 mm, C18, 5 µm 
Flow Rate 1.5 mL/minute 
Column Temperature 40°C 
Detection Wavelength 254 nm 
Injection Volume 20 µL 
Mobile Phase: Add 1.2 mL Glacial Acetic acid to 1000 mL water, Degas and filter the mixture 

Standard Preparation: 
Dissolve 50 mg of Acyclovir SRS into a 50 mL volumetric flask, add 10 mL of 0.1 N Sodium Hydroxide solution by sonication and dilute to 50mL with water. Dilute 5 mL of resulting solution to 50 mL of water. 

Sample Preparation: 
Transfer tablet powder (equivalent to 50 mg of Acyclovir) in to a 50 mL volumetric flask and add 10 mL of 0.1N Sodium Hydroxide dilute up to the mark with water, dilute up to the mark with same. Dilute 5mL of resulting solution to 50mL with water. 

Inject standard preparation in five replicate & record the chromatogram. Inject sample preparation in duplicate, record the chromatogram & calculate the percent of assay by using the following formula: 

% Assay of Acyclovir by using the formula =

     At = Average Area of Sample solution
     As = Average Area of Standard solution
    Ws = Weight of Standard
    Wt = Weight of Sample
    ATW = Average tablet weight
    P = Potency of Standard
    L = Label Claim 

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