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Biomedical subjects

P Folb

Publications and source records attributed to P Folb.

5 recordsLinked to original sources
PubMed2002

Widespread distribution of a single drug rifampicin formulation of inferior bioavailability in South Africa.

A pharmacokinetic study of rifampicin, isoniazid, pyrazinamide and ethambutol in 118 tuberculosis patients revealed low and variable concentrations of rifampicin after 2 months of treatment on standard daily doses. A group of 53 patients exposed to specific batches of formulations containing rifampicin alone showed particularly low and variable levels of the drug. The national drug regulatory authority subsequently withdrew the batches in question, as sufficient bioavailability data had not been submitted after what the manufacturer had considered to be a minor formulation change. The evidence supports initiatives to implement bioavailability testing of new formulations (and of established formulations subsequent to changes in the manufacturing process) prior to distribution. Concerns about the bioavailability of rifampicin-containing products, including those with adequate dissolution profiles, should not be confined to fixed-dose combination anti-tuberculosis drugs, but should also be applied to single drug formulations.

Adult↗
PubMed1998

What role can public health institutions play in drug development for the poor? A case study of artesunate.

Although the strategy of artesunate development was orchestrated from within WHO's Special Programme for Research and Training in Tropical Diseases, it relies heavily upon an alliance of scientist, laboratories, industry, regulators and ministries of health to ensure the public health outcome. This development strategy has transformed the way in which WHO does business, both within and outside the Organization. In essence, each and every player has rallied in the challenge to reduce the discrepancy between need and availability of a drug that can has the potential to reduce mortality form the disease.

Africa↗
PubMed1996

Tunicamycin potentiates drug cytotoxicity and vincristine retention in multidrug resistant cell lines.

Tunicamycin (TM), an inhibitor of glycoprotein processing, was investigated for its potential to reverse the multiple drug resistance (MDR) phenotype. When TM was added in vitro to drug-resistant NIH-3T3-MDR and KB-8-5-11 cells, they developed an increased sensitivity to doxorubicin, epirubicin, vincristine and colchicine. Similarly, the sensitivity of NIH-3T3-MDR cells to cisplatin was also enhanced by TM. In the presence of TM, drug-sensitive NIH-3T3-parental cells exhibited greater susceptibility to the toxic effects of doxorubicin, epirubicin, vincristine (marginally significant), and colchicine, but not to cisplatin. Tunicamycin-treated drug-sensitive KB-3-1 cells showed an increased response to vincristine, but not to the other anticancer drugs. Pretreatment with TM inhibited glycoprotein synthesis in all the cell lines. Neither prior exposure to, nor co-incubation with TM, influenced the uptake of vincristine (VCR) in the various cell lines. However, NIH-3T3-MDR cells accumulated less VCR than their drug-sensitive controls and also exhibited reduced efflux of the drug when treated with TM. There were no significant differences in the levels of intracellular VCR uptake between drug-sensitive KB-3-1 and KB-8-5-11 cells. Tunicamycin increased intracellular VCR retention in KB-8-5-11 and NIH-3T3-MDR cells, but not in NIH-3T3-parental cells. However, drug-sensitive KB-3-1 cells expressed reduced VCR retention in response to TM exposure, indicating that correlations between VCR toxicity and its retention in the presence of TM should be made with caution. The results suggest that the enhancement of intracellular VCR retention in MDR cells lines caused by TM is likely to be the result of inhibition of VCR efflux. Inhibition of glycoprotein synthesis during TM exposure may account for the changes in VCR efflux and retention observed in the MDR cell lines. The enhancement of cisplatin cytotoxicity in NIH-3T3-MDR cells after exposure to TM is an interesting observation, since it is generally believed that agents which modify the MDR phenotype do not show a sensitising effect to cisplatin. These findings may have applications in the reversal of drug resistance.

Antineoplastic Agents↗
PubMed1987

Aluminium loading during therapeutic plasma exchange.

Graphite furnace atomic absorption spectroscopy was used to demonstrate a fivefold increase in the median plasma aluminium levels of four patients undergoing therapeutic plasmapheresis. This plasma aluminium loading resulted from contamination of albumin incorporated in the replacement fluids and took place during its preparation, with albumin aluminium levels of 646, 669, and 715 micrograms/liter present in three representative samples. Aluminium overload may result in the development of encephalopathy and osteomalacia in patients with renal impairment, indicating the need to monitor aluminium levels in the albumin-containing replacement fluids to avoid this potential hazard.

Aluminum↗