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

Abstract

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 one fifth is reportedly substandard in the global drug market. The aim of this study was to determine the quality of R-FDC and rifampicin single formulation anti-TB drugs in Kampala city, Uganda. Eight private and five public pharmacies were randomly selected, the drug samples were purchased and in the latter case obtained free of charge. Drug quality was assessed by visual inspection, weight uniformity, dissolution, and assay. Fifteen batches of anti-TB drugs were collected; 13 R-FDC and two rifampicin single dose 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 dose 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), eight of which were R-FDC and two rifampicin single dose formulations. Of the R-FDC drugs, four samples (4/12: 33.3%) failed the assay test and were all not in the NDR. All the R-FDC drug samples passed the dissolution, visual inspection and weight uniformity tests. All rifampicin single dose formulations passed assay, visual, and weight uniformity tests and only one failed the dissolution test. Unregistered and sub-standard rifampicin anti-TB drugs are common in drug outlets on the Ugandan drug market. These substandard drugs pose a risk to patients such as treatment failure that leads to increased cost of treatment and possibly loss of lives.Key words: Rifampicin, fixed-dose combination, post-market quality, drug quality, assay. INTRODUCTIONTuberculosis (TB) is the world's leading curable infectious killer disease (World Health Organization (WHO), 2008). The WHO estimated global TB prevalence as 14.4 million with the incidence of 363/100,000 population and 355/100,000 population in Africa and Uganda, respectively (WHO, 2008). Uganda being one of the most highly TB burdened countries of the world is faced with the challenge of drug resistance to TB treatment. In a previous study by Bertzel (1999), the reported rate of Multi-Drug Resistant TB (MDR-TB) in Uganda was slightly over 4% in *Corresponding author E-mail: ocanmoses@gmail.com. Tel: +256-712-234364. in patients with a history of prior treatment and about 1% in patients with no history of prior treatment. A number of factors contribute to development of resistance to TB medications. Among these factors is use of substandard medications in TB treatment and lack of patient supervision (Pecoul, 1999;Panchagnula, 2004).Rifampicin (3-[4-methyl-1-piperazinyl] iminomethyl rifamycin SV) is a semi synthetic macro cyclic antibiotic derived from Streptomyces mediterranei (Martindale, 2002). It is o...

A pharmaceutical monitoring system to assess the quality of antituberculosis drug products used in Mauritania

“…sampling strategy has to be followed to collect a large number of units of each drug product, sampled from different points of the supply-chain, to perform all pharmacopoeial tests. Some studies indicated correct quality of the drug products tested although these studies did not follow the recommendations of European or United States Pharmacopeia, because they did not calculate the acceptance value (AV) for uniformity of dosage units, or used an incorrect number of units [6,7]. In this regard, it is very common to find in African research groups studies conducted with the minilab, which is a semi-quantitative technique that is not suitable for the detection of substandard drug products [8].…”