Funding for the study was provided by SIDA/SAREC through the WHO/DAP operational research programme.

Aidan Chidarikire, Director of Pharmacy Services (MOHCW) provided encouragement and approval for this collaborative project involving the Ministry of Health and Child Welfare (MOHCW) in Harare and the Action Programme on Essential Drugs of the World Health Organization, in Geneva.

Charles Kaseke, Controller, Government Medical Stores (GMS) unhesitatingly authorized the sampling from stock. Gerrit Weeda put procedures in place for retaining manufacturers' batch certification. Mark Ros set up a user friendly dBase programme in the last few weeks before his departure. Kenneth Makumbirofa managed the monitoring of stock at Bulawayo Medical Stores with startling efficiency and assisted in sample collection.

Perhaps the most enjoyable part of the whole study was the cooperation with district pharmaceutical staff in sample collection. Facilitation was provided by Godfrey Tirivanhu, Liberty Chinguwa, Ralph Ncube, Sue Lau Gooey and Felicity (Flick) Mayfield.

Ian Matondo, Director, and staff of the Zimbabwe Regional Drug Control Laboratory (ZRDCL) deserve congratulation and thanks for the enormous volume of work required to produce the test results. Tapuwa Muchemwa, Principal Analyst at ZRDCL, established the protocols for testing at the outset of the study and assisted in a large part of sample collection. E. Murwisi and L. Siziba carried the work through to the end, with assistance of many analysts, not mentioned here by name. Ms Kanjere and Beauty Dodzo were custodians for the study samples.

Margit Handlos of the Chemical laboratory, National Board of Health, Denmark assisted in complementary testing of samples for comparison, and will hopefully continue cooperation with ZRDCL.

Ellen Chitura handled a huge volume of documentation with much finesse and was infallible in data entry. Nomusa Chitepo was quick to respond to appeals for help with database problems.

Martha Anker (Department of Epidemiological and Statistical Validation, WHO) gave advice and clear explanations on statistical analysis when required.

Finally, this operational research was possible only through the framework of logistic and administrative support, and time allowance provided under the Zimbabwe Essential Drugs Action Programme (ZEDAP), MOHCW, a programme receiving technical and financial support from the Danish International Development Agency (DANIDA).