Abacavir, Lamivudine, and Zidovudine Tablets

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Abacavir, Lamivudine, and Zidovudine Tablets contain an amount of abacavir sulfate, lamivudine, and zidovudine equivalent to NLT 90.0% and

NMT 110.0% each of the labeled amounts of abacavir (C H N O), lamivudine (C H N O S), and zidovudine (C H N O ), respectively.

2 IDENTIFICATION

A. The retention times of the major peaks of the Sample solution correspond to those of abacavir sulfate, lamivudine, and zidovudine from

the Standard solution, as obtained in the Assay.

B. The UV absorption spectra of the major peaks of the Sample solution correspond to those of abacavir sulfate, lamivudine, and zidovudine

from the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 Procedure

Solution A: 1.9 g/L of ammonium acetate in water. Adjust with glacial acetic acid to a pH of 3.9.

Solution B: Methanol

Mobile phase: See Table 1.

System suitability solution: Dissolve the contents of 1 vial of USP Lamivudine Resolution Mixture C RS in 2.5 mL of Solution A. [Note—One vial of USP Lamivudine Resolution Mixture C RS contains 0.8 mg of USP Lamivudine Resolution Mixture C RS.]

Standard solution: 0.35 mg/mL of USP Abacavir Sulfate RS, 0.15 mg/mL of USP Lamivudine RS, and 0.30 mg/mL of USP Zidovudine RS in Solution A. Sonicate to dissolve prior to nal dilution.

Sample stock solution: Nominally 3 mg/mL of abacavir, 1.5 mg/mL of lamivudine, and 3 mg/mL of zidovudine in Solution A prepared as follows. Transfer NLT 5 Tablets to a suitable volumetric ask. Add Solution A to about 50% of the nal ask volume and shake for NLT 30 min to disperse the Tablets. Dilute with Solution A to volume. Pass through a suitable lter.

Sample solution: Nominally 0.30 mg/mL of abacavir, 0.15 mg/mL of lamivudine, and 0.30 mg/mL of zidovudine in Solution A from Sample stock solution

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 270 nm. For Identication B, use a diode array detector in the range of 220–400 nm.

Column: 4.6-mm × 15-cm; 5-μm packing L1

Column temperature: 30°

Flow rate: 1 mL/min

Injection volume: 10 μL

3.2 System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for lamivudine-S-oxide and lamivudine-R-oxide, in relation to the lamivudine peak, are 0.36 and 0.40, respectively; the relative retention times for lamivudine diastereomer and lamivudine are 0.96 and 1.0, respectively, System suitability solution.]

Suitability requirements

Resolution: NLT 1.2 between lamivudine carboxylic acid and lamivudine-S-oxide; NLT 1.2 between lamivudine diastereomer and

lamivudine, System suitability solution

Relative standard deviation: NMT 2.0% each for abacavir, lamivudine, and zidovudine, Standard solution

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of abacavir (C₁₄H₁₈N₆O) in the portion of Tablets taken:

Result = (r_u /r_s) × (C_s/C_u) × (M_r1/M_r2) × 100

r_u = peak response of abacavir from the Sample solution

r_s = peak response of abacavir from the Standard solution

C_s = concentration of USP Abacavir Sulfate RS in the Standard solution (mg/mL)

C_u = nominal concentration of abacavir in the Sample solution (mg/mL)

M_r1 = molecular weight of abacavir multiplied by 2, 572.66

M_r2 = molecular weight of abacavir sulfate, 670.74

Calculate the percentage of the labeled amount of lamivudine (C₁₀H₁₃N₅O₄) in the portion of Tablets taken:

Result = (r_u /r_s) × (C_s/C_u) × 100

r_u = peak response of lamivudine from the Sample solution

r_s = peak response of lamivudine from the Standard solution S

C_s = concentration of USP Lamivudine RS in the Standard solution (mg/mL)

C_u = nominal concentration of lamivudine in the Sample solution (mg/mL)

Calculate the percentage of the labeled amount of zidovudine (C₁₀H₁₃N₅O₄) in the portion of Tablets taken: 10 135

Result = (r_u /r_s) × (C_s/C_u) × 100

r_u  = peak response of zidovudine from the Sample solution

r_s  = peak response of zidovudine from the Standard solution S

C_s = concentration of USP Zidovudine RS in the Standard solution (mg/mL)

C_u = nominal concentration of zidovudine in the Sample solution (mg/mL)

Acceptance criteria: 90.0%-110.0% each of the labeled amounts of abacavir, lamivudine, and zidovudine

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711).

Medium: 0.1 N hydrochloric acid, degassed; 900 mL

Apparatus 2: 75 rpm

Time: 30 min

Standard solution 1: 0.35 mg/mL of USP Abacavir Sulfate RS in Medium. Sonicate to dissolve prior to final dilution.

Standard solution 2: 0.15 mg/mL of USP Lamivudine RS in Medium. Sonicate to dissolve prior to nal dilution.

Standard solution 3: 0.30 mg/mL of USP Zidovudine RS in Medium. Sonicate to dissolve prior to nal dilution.

Sample solution: Pass a portion of the solution under test through a suitable lter.

4.2 Instrumental conditions

Mode: UV

Wavelength range: 240–320 nm

Cell: 0.05 cm

Blank: Medium

Analysis: The calculations of the percentages dissolved are performed using multi-component analysis software.

Samples: Standard solution 1, Standard solution 2, Standard solution 3, and Sample solution

Calculate the percentage of the labeled amount each of abacavir, lamivudine, and zidovudine dissolved.

Tolerances: NLT 80% (Q) each of the labeled amount of abacavir, lamivudine, and zidovudine is dissolved.

• Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

5.1 Organic Impurities

Solution A, Solution B, Mobile phase, System suitability solution, Standard solution, Sample stock solution, Sample solution,

Chromatographic system, and System suitability: Proceed as directed in the Assay.

5.2 Analysis

Sample: Sample solution

Calculate the percentage of any individual abacavir related impurity and any unspecied impurity in the portion of Tablets taken:

Result = r_u /{Σ[r_u  × (1/F)] + r_t } × (1/F) × 100

r_u = peak response of each individual abacavir related impurity or any unspecied impurity

F = relative response factor for each individual impurity (see Table 2)

r_t = sum of the peak responses of abacavir, all abacavir related impurities, and all unspecied impurities

Calculate the percentage of any individual lamivudine related impurity in the portion of Tablets taken:

Result = (r_u /r_t ) × 100

r_u = peak response of each individual lamivudine related impurity

r_t  = sum of the peak responses of lamivudine and all lamivudine related impurities

Calculate the percentage of any individual zidovudine related impurity in the portion of Tablets taken:

Result = r_u/(r_u x (1/F)] +r_t ) x (1/F) x 100

r_u = peak response of each individual zidovudine related impurityrelative response factor for each individual zidovudine impurity (see Table 2) F = 1

r_t  = sum of the peak responses of zidovudine and all zidovudine related impurities

Acceptance criteria: See Table 2. The reporting threshold is 0.05%.

^a Lamivudine related impurity.

^b This is a process impurity and included for peak identification purposes.

^c (2RS,5SR)-5-(Cytosine-1-yl)-1,3-oxathiolane-2-carboxylic acid.

^d 1-[(2R,3S,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine S-oxide.

^e 1-[(2R,3R,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine S-oxide.

^f Zidovudine related impurity.

⁹1-[(2RS,5RS)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine.

^h1-[(2RS,5SR)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]uracil.

ⁱ Abacavir related impurity.

^j N⁶-Cyclopropyl-9H-purine-2,6-diamine.

^k [(1S,4R)-4-(2,6-Diamino-9H-purin-9-yl) cyclopent-2-enyl]methanol.

^l 3'-Chloro-3'-deoxythymidine.

^m For any unspecified impurity, report the largest impurity observed, excluding descyclopropyl abacavir, thymine, and other process impurities. Percent for any unknown is based on total abacavir related peak areas.

ⁿ Drug process impurities are not included in the total impurities content, except thymine and descyclopropyl abacavir, which are included in the total zidovudine related impurities and total abacavir related impurities, respectively.

6 ADDITIONAL REQUIREMENTS

• Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.

• USP Reference Standards 〈11〉

USP Abacavir Sulfate RS

USP Lamivudine RS

USP Lamivudine Resolution Mixture C RS

This is a mixture of lamivudine and the following impurities (other impurities may also be present):

Uracil;

Pyrimidine-2,4(1H,3H)-dione.

C₄H₄N₂O₂     112.09 

Lamivudine-uracil derivative;

1-[(2RS,5SR)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]uracil.           C₈H₁₀N₂O₄S      230.24

Cytosine;

4-Aminopyrimidin-2(1H)-one.                C₄H₅N₃O             111.10

Lamivudine-S-sulfoxide;

1-[(2R,3S,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine S-oxide.       C₈H₁₁N₃O₄S          245.26

Lamivudine-R-sulfoxide;

1-[(2R,3R,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine S-oxide.         C₈H₁₁N₃O₄S        245.26

Lamivudine carboxylic acid;

(2RS,5SR)-5-(Cytosine-1-yl)-1,3-oxathiolane-2-carboxylic acid.           C₈H₉N₃O₄S                243.24

Lamivudine diastereomer;

1-[(2RS,5RS)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine.            C₈H₁₁N₃O3S            229.26

Salicylic acid;

2-Hydroxybenzoic acid..       C₇H₆O₃            138.12

USP Zidovudine RSA (USP 1-May-2021)