title: The differences between the branded and generic medicines using solid dosage forms: In-vitro dissolution testing.
abstract: BACKGROUND
  Dissolution is the amount of substance that goes into solution per unit time under standardised conditions of liquid/solid interface, solvent composition and temperature. Dissolution is one of the most important tools to predict the in-vivo bioavailability and in some cases to determine bioequivalence and assure interchangeability.
  
  
  OBJECTIVE
  To compare the differences in dissolution behaviour of solid dosage forms between innovators (reference products) and their generic counterparts (tested products).
  
  
  METHODS
  Four replicates for each batch of 37 tested medicines was carried out using A PT-DT70 dissolution tester from Pharma Test. A total of 13 branded medicines and 24 generic counterparts were obtained locally and internationally to detect any differences in their dissolution behaviour. They were tested according to the British Pharmacopeia, European Pharmacopeia and the US Pharmacopeia with the rate of dissolution determined by ultra-violet Spectrophotometery.
  
  
  RESULTS
  Most tested medicines complied with the pharmacopoeial specifications and achieved 85% dissolution in 60 min. However, some generic medicines showed significant differences in dissolution rate at 60 and 120 min. Many generic medicines showed a slower dissolution rate than their branded counterparts such as the generic forms of omeprazole 20 mg. Some showed an incomplete dissolution such as the generic form of nifedipine 10 mg. Other generics showed faster dissolution rate than their branded counterpart such as the generic forms of meloxicam 15 mg. Moreover, some generics from different batches of the same manufacturer showed significant differences in their dissolution rate such as the generic forms of meloxicam 7.5 mg. Nevertheless, some generic medicines violated the EMA and the FDA guidelines for industry when they failed to achieve 85% dissolution at 60 min, such as the generic form of diclofenac sodium 50 mg.
  
  
  CONCLUSIONS
  Most medicines in this study complied with the pharmacopeial limits. However, some generics dissolved differently than their branded counterparts. This can clearly question the interchangeability between the branded and its generic counterpart or even among generics.
authors.affiliation: William Harvey Research Institute, Barts and The London, School of Medicine and Dentistry, Queen Mary University of London EC1M 6BQ, UK ; UAE General Hospital, Abu Dhabi, United Arab Emirates.
authors.forename: Mubarak Nasser
authors.initials: MN
authors.lastname: Al Ameri
authors.affiliation: William Harvey Research Institute, Barts and The London, School of Medicine and Dentistry, Queen Mary University of London EC1M 6BQ, UK.
authors.forename: Nanda
authors.initials: N
authors.lastname: Nayuni
authors.affiliation: UAE General Hospital, Abu Dhabi, United Arab Emirates.
authors.forename: K G
authors.initials: KG
authors.lastname: Anil Kumar
authors.affiliation: William Harvey Research Institute, Barts and The London, School of Medicine and Dentistry, Queen Mary University of London EC1M 6BQ, UK.
authors.forename: David
authors.initials: D
authors.lastname: Perrett
authors.affiliation: William Harvey Research Institute, Barts and The London, School of Medicine and Dentistry, Queen Mary University of London EC1M 6BQ, UK.
authors.forename: Arthur
authors.initials: A
authors.lastname: Tucker
authors.affiliation: William Harvey Research Institute, Barts and The London, School of Medicine and Dentistry, Queen Mary University of London EC1M 6BQ, UK.
authors.forename: Atholl
authors.initials: A
authors.lastname: Johnston
keywords: Absorption; Differences between the branded and generic medicines; Dissolution methods; IVIVC; In-vitro dissolution