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A viroid has been purified from avocado leaves infected by sunblotch disease and designated the avocado sunblotch viroid. It is a covalently closed circular RNA molecule with a molecular weight lower than that of chrysanthemum stunt viroid and citrus exocortis viroid while hybridization analysis with 32P-labeled complementary DNA indicated that it is a single RNA species. It could be detected as a stainable RNA band on polyacrylamide tube gel electrophoresis of partially purified extracts of only two of four avocado isolates with positive symptoms of sunblotch disease. However, the viroid was detected in all four isolates by hybridization analysis with 32P-complementary DNA; this procedure has potential use for the rapid indexing of sunblotch disease since the viroid was not present in an isolate of healthy avocado. It has yet to be shown that the viroid is the causative agent of sunblotch disease.

The particulate contamination in 19 formulations of solutions in ampoules supplied by eight South African manufacturers, thirty-three batches in all, was analysed using a HIAC PC 320 light blockage particle analyser linked to a CMB 60 sensor. Results showed that the level of contamination was generally low and that, where comparisons could be made, manufacturers both of the ampoules and the solutions maintained similarly high standards. Problems in this field appeared to be related to the formulation or the quality of the raw material.

The metabolism of phenylbutazone has been investigated in female rats dosed with the drug by gavage. The major route of excretion is via the urine; 50% of the dose being excreted in the first 24 h. A small percentage of the dose is excreted in the faeces. Following administration of 14C-phenylbutazone, five labelled, unconjugated hydroxy compounds were identified in the urine by t.l.c. and autoradiography; both hydrolysable and non-hydrolysable conjugates were found. Aqueous extracts of faeces contained O conjugates of oxyphenbutazone and 4-hydroxy-oxyphenbutazone (which may be a decomposition product). Urine metabolites soluble in organic solvents were quantified by inverse isotope dilution assay and spectrophotometric analysis. The major metabolite is the gamma-hydroxy derivative of phenylbutazone present both as the lactone and as the straight-chain compound, while oxyphenbutazone and p, gamma-dihydroxyphenylbutazone are minor metabolites.

The particulate contamination in 12 formulations of antibiotic solutions in vials packed as dry powders from five South African sources has been analysed quantitatively using a HIAC PC 320 light blockage particle analyser linked to a CMB 60 sensor. Results showed that the level of particulate contamination fell well within the limits set by the USP XXIst Edition for Small Volume Parenterals although four formulations contained some particles greater than or equal to 50 micron. There was no apparent difference between the quality of the same antibiotics from different sources or between vials of the same antibiotics packed in different strengths.