Struvite formation for enhanced dewaterability of digested wastewater sludge.

One of the main advantages of controlled struvite formation in digested sludge is an improvement in dewaterability of the digested sludge, which eventually leads to lower volumes of dewatered sludge that need to be transported. The effects of the control parameters for struvite formation, magnesium concentration and pH, on digested sludge dewaterability were investigated and are discussed in relation to the efficiency of struvite formation. Laboratory experiments with digested activated sludge were performed in a 20 L batch reactor. CO2 was stripped from the digested sludge using a bubble aerator and magnesium chloride was added to induce struvite formation. The dewaterability of the sludge was determined by gravity filtration tests. In the experiments, either the pH or the molar magnesium to phosphate ratio (Mg:PO4) was varied. The results confirm improved sludge dewaterability after struvite formation. Magnesium to phosphate ratios above 1.0 mol/mol did not further improve dewaterability. The addition of magnesium did not prevent the need for polymer addition for sludge dewatering. An increase in pH led to a deterioration in dewaterability. The best dewaterability results were found at the lowest pH value (pH = 7.0), while stirring the sludge instead of using the bubble aerator. At these settings, an orthophosphate removal of around 80% was achieved.

Particulate contamination in solutions of antibiotics packed as dry powders in vials.

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.

Bioavailability of amfepramone hydrochloride sustained release pellets formulation in healthy subjects.

The relative bioavailability and pharmacokinetic profile of two amfepramone (diethylpropion) hydrochloride oral preparations were evaluated in 12 normal volunteers using a newly developed gas-liquid chromatographic procedure to monitor the unchanged drug and its two major metabolites in urine, plasma and saliva. The sustained release pellets formulation (Regenon retard) provided excellent bioavailability and gave broad plateau levels extending over 6 to 8 h after administration, which were intermediate between the "peaks and troughs" shown by the same total dose of the free drug in three equal portions at 4-h intervals.

Simultaneous determination of amfepramon and its two major metabolites in biological fluids by gas liquid chromatography.

Sensitive and specific procedures based on gas liquid chromatography for the identification, separation and determination of amfepramon (diethylpropion) and its major metabolites ethylaminopropiophenone and diethylnorpseudoephedrine in human plasma, saliva and urine have been described. Acidification of the biological fluid samples has improved the stability of the compounds under conditions of storage.

Sugar-free liquid pharmaceuticals.

With the reported increased incidence of dental disease in chronically ill children receiving sugar-containing medicines, health care personnel should be made aware of the availability of sucrose-free paediatric preparations. The list of sugar-free liquid preparations for oral use presented will require updating as more products are reformulated to avoid inclusion of fermentable carbohydrates.

Ethanol content of some pharmaceuticals available in the RSA.

The Medicines Control Council is concerned about the influence of the simultaneous ingestion of alcohol and medicines on certain psychomotor functions and the consequent inability of the consumer to perform tasks which require mental clarity. Health care personnel should be aware of the alcohol content of medications when counselling patients receiving drugs against alcoholism or patients who should avoid alcohol. A compilation, short-listed from over 300 ethanol-containing prescription and non-prescription drug products available in the RSA, is presented.

Analysis of particulate contamination in ampoules using a light blockage particle analyser.

A method of opening ampoules without introducing particles has been developed and the level of particulate contamination in a number of ampoule solutions using a light blockage particle analyser (HIAC) has been determined. Low levels of contamination were found and a method of setting limits of particulate contamination in ampoules is suggested.

Particulate contamination in ampoules.

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.

Determination of polythiazide in pharmaceutical dosage forms by high-pressure liquid chromatography.

A method is presented for the quantitative analysis of polythiazide tablets by high-pressure liquid chromatography. The powdered tablets are extracted with methanol, containing quinoline as the internal standard, and assayed by comparison of peak heights after liquid chromatography. The chromatographic conditions employed may be adapted for the determination of many other thiazide and nonthiazide diuretics.