Drugs from micro-organisms

Ophthalmic products have to be manufactured sterile and be free from micro-organisms. Once opened, the sterility of a multidose product must be maintained during its period of use. This is usually required for at least 4 weeks, after which the product is discarded. If the drug itself does not possess antimicrobial properties, then an antimicrobial preservative must be included in the formulation to ensure that any micro-organisms accidentally introduced during use are destroyed. 

Intracellular infections were found to be a field of interest for drug delivery by means of nanospheres. Indeed, infected cells may constitute a reservoir for micro organisms, which are protected from antibiotics inside lysosomes. The resistance of intracellular infections to chemotherapy is often related to the low uptake of commonly used antibiotics or to their reduced activity at the acidic pH of lysosomes. To overcome these effects, the use of ampicillin, a p lactam antibiotic, bound to nanospheres was proposed as endocytozable formulation. The effectiveness of polyisohexylcyanoacrylate (PIHCA) nanospheres was tested in the treatment of two experimental intracellular infections. 

Significant differences in the extent of distribution of drugs, particularly lipid-soluble organic bases, are usual between ruminant and monogastric species. After parenteral administration, lipophilic bases diffuse passively from the systemic circulation into ruminal fluid (pH 5.5-6.5), where they become trapped by ionization. These drugs are slowly reabsorbed or, if they possess fimctional groups suitable for metabolism by hydrolysis or reduction, they may be partially inactivated by ruminal micro-organisms. 

L-5178Y cells and a number of micro-organisms. Its acute toxicity is low a dose of 2000 mg/kg injected i.p. into mice is tolerated by the animals. Recent studies have suggested that the activity of this compound results from in situ hydrolysis of the drug by j -glucuronidase to mycophenolic acid [221a]. 

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