Substandard rifampicin based anti-tuberculosis drugs common in Ugandan drug market

Abstract

Background: Tuberculosis (TB) is an important curable infectious disease in Uganda; its treatment however is facing a challenge of increasing drug resistance. Although Rifampicin containing Fixed-Dose Combination (R-FDC) drugs are a mainstay in TB treatment, about 1/5 are reportedly substandard in the global drug market. Aim: To determine the quality of R-FDC and rifampicin single formulation anti-TB drugs in Kampala city, Uganda. Method: Eight private and five public pharmacies were randomly selected, and drug samples purchased or obtained free of charge respectively. Drug quality was assessed using visual inspection, weight uniformity, dissolution, and assay. Results: Fifteen batches of anti-TB drugs were collected, 13 R-FDC and 02 rifampicin single formulations. One batch of R-FDC collected from a public pharmacy was not assayed as it had passed its expiry date by the time of analysis. Of the samples analyzed, six batches of R-FDC and two of rifampicin single formulations were purchased from private pharmacies. The other six batches of R-FDC were obtained from public pharmacies. Ten samples (10/14: 71.4%) were not in the National Drug Register (NDR) of which eight were R-FDC and two rifampicin single formulations. Of the R-FDC drugs, four samples (4/12: 33.3%) failed the assay test and all were not in the NDR. All the R-FDC drug samples passed the dissolution, visual and weight uniformity tests. All rifampicin single formulations passed assay, visual, and weight uniformity tests while one failed the dissolution test. Conclusion: Unregistered and sub-standard rifampicin anti-TB drugs are common in drug outlets in Ugandan drug market.