RESUMEN
Solid dispersions (SDs) are resulted by dispersion of drug in biologically inert matrix. They can be used to increase the solubility of a drug with low aqueous solubility, thereby improving its oral bioavailability. Higher drug dissolution rates from a SD can be facilitated by optimizing the wetting characteristics of the compound surface, as well as increasing the interfacial area available for drug dissolution. Although the latter can be easily accomplished by, for example: decreasing the particle size of the drug powder but micronized powders may result in further complications as they occasionally tend to agglomerate. A more preferable solution would be to introduce the drug in the form of a molecular dispersion. The aim of present study was to enhance the dissolution rate of diclofenac a practically less water-soluble drug. The same was done by preparation of solid dispersions of the drug employing different ratios of established polymers. This was done by using polymers namely; hydrophilic polymer β-cyclodextrins, PVP and PEG. The kneading method was used to prepare solid dispersions in various ratios with polymer. The dissolution data was studied for all the three formulations. The data obtained was compared with that of physical mixtures containing drug, polymer and lactose in the same ratio as that of solid dispersions. The dissolution data showed that best release was obtained in formulation f1 containing beta –cyclodextrins, PVP and PEG as polymer. The comparative data showed 98% release at approximately 4 hours with polymer β –cyclodextrins, whereas, 90% and 88% release were obtained using PEG and PVP respectively in the same time frame.
RESUMEN
An enrichment culture technique was used to isolate bacterial strains responsible for the biodegradation of profenofos in a soil from Hubei province of central China. Two pure bacterial cultures, named W and Y, were isolated and subsequently characterized by sequencing of 16S rRNA genes and biochemical tests. Isolate W showed 96 percent similarity to the 16S rRNA gene of a Pseudomonas putida unlike Y which showed 99 percent similarity to the 16S rRNA gene of Burkholderia gladioli. Both strains grew well at pH 5.5-7.2 with a broad temperature profile ranging from 28º to 36 ºC. Bioremediation of profenofos-contaminated soil was examined using soil treated with 200 ug g-1; profenofos resulted in a higher degradation rate than control soils without inoculation. In a mineral salt medium (FTW) reduction in profenofos concentration was 90 percent within 96 hours of incubation. A literature survey revealed that no data is available regarding the role of Burkholderia gladioli on pesticide biodegradation as well as on profenofos.