Reference samples (CMS samples)
For each drug, all incoming batches were monitored on arrival at the two purchasing central medical stores. Batch number and quantity received were recorded. A reference sample from each incoming batch was retained and stored under refrigeration. A small number of these were sent for laboratory testing at the beginning of the study to provide an early indication of initial quality. The majority were held (with package seal intact) in order to provide a match (GMS sample) for samples which would later be collected from the field (facility samples).
Local manufacturers tended to deliver small quantities frequently (every three to four months). Since one local manufacturer produced small quantities of capsules per batch (a limitation of the equipment used), it was not possible to keep a reference sample of each and every batch in these cases. However, a record was kept of the number of units received per batch to ensure that the number of batches retained as samples was sufficient to be representative (satisfying the "square root sampling" criterion).
At hospitals and health centres, two samples of each drug were taken: (1) the oldest batch present; and (2) (if possible) the same batch as the one taken as reference sample at central medical stores.
The following information was collected for each drug sample on a serially numbered form: (1) drug identification information (as for GMS sample); (2) stock movement record: the date that the drug batch was received at the facility, indicated on the stock card; (3) remarks: any local storage factors affecting product quality, e.g. adverse conditions in drug store room, refrigeration/room temperature storage for ergometrine injection; (4) facility identification: name of the facility, date of sampling; (5) coded information: district facility type, climate and transport method; (6) classification: endpoint sample or longitudinal sample.
Quantity of drug dose units sampled, labelling and packaging materials
For the eight oral drugs, 100 dose units (tablets and capsules) were packed in amber glass bottles or plastic polymer jars with screw cap seals. The container was labelled with drug name, batch number, facility name, sampling date and sample form number. An insulated cooler box was used for transportation. For the five injectable drugs, 20 dose units (vials or ampoules) were packed in rigid cardboard boxes and similarly labelled. At some facilities it was only possible to obtain 10 ampoules in the case of ergometrine injection and epinephrine injection. Transportation was in an insulated cooler box with freezer packs.
Schedule for sample collection
Reference samples were collected for a period of one year (1991-1992). The sample collection from health facilities was scheduled to fit in with other programme activities and field trips. One to three districts were visited every two to three months over a period of 18 months. The field sample collection was completed by the end of 1992.