In vitro comparative quality evaluation of different brands of carbamazepine tablets commercially available in Dessie town, Northeast Ethiopia.

Background: Good-quality drugs that fulfill the regulatory parameters and are produced per the current good manufacturing practice (cGMP) standards are very critical for the best therapeutic outcomes. However, the variety of branded drugs circulation in the market often put clinicians and pharmacists in a difficult situation of choice due to the possibility of interchangeability among brands, so we should ascertain the quality of the various brands of drugs, available in the drug market. The purpose of the study was to evaluate the quality and physicochemical equivalence of six brands of carbamazepine tablets that are commercially available in Dessie town, Northeast Ethiopia.

Methods: An experimental study design was used. Six different brands of carbamazepine tablets were purchased from community pharmacies in Dessie town, Northeast Ethiopia, which were selected using simple random sampling methods. Identification, weight variation, friability, hardness, disintegration, dissolution test, and assay for the content of active ingredients were evaluated according to the procedures described in the United States Pharmacopeia (USP) and British Pharmacopeia (BP), and the results were compared with USP and BP standards. The difference (f1) and similarity (f2) factors were calculated to assess in vitro bioequivalence requirements.

Results: The identification test results revealed that all samples contained the stated active pharmaceutical ingredients and all brands of carbamazepine tablets complied with the official specification for weight variation, friability, and hardness tests. The percentage concentration of carbamazepine was found in the range of 97.85 to 102.09, which met the USP specification of 92% to 108% of the stated amount. Similarly, all samples fulfilled disintegration time (i.e., ≤ 30 min) except brand CA1 (34.183 min) and dissolution tolerance limits (i.e., Q ≥ 75% at 60 min), which was found in the range of 91.673% -97.124%. The difference factor (f1) values were < 15 and the similarity factor (f2) values were > 50 for all the tested brands of carbamazepine tablets.

Conclusion: The present study revealed that all brands of carbamazepine 200 mg tablets met the quality control parameters as per pharmacopoeial specifications except the disintegration test of brand CA1, and could be used each brand interchangeably to achieve the desired therapeutic effect.