| Chloramphenicol is produced by the Streptomyces venezuelae, its chemical structure contains nitrophenyl, propylene glycol and dichloro-acetamide. The antimicrobial activity is mainly related with propylene glycol. Chloramphenicol is white or slight yellow-green needle-like, long flaky crystal or crystalline powder with bitter taste. It is soluble in methanol, ethanol, propylene glycol and acetone. It is stable at dry condition and fairly stable in weak acid and neutral solutions. It could easily become invalid when it meet with alkali. Chloramphenicol inhibites Gram-positive and Gram-negative bacteria, and the latter is stronger. Antibacterial mechanism is that chloramphenicol combines with 50 S ribosomal subunit, inhibites peptide acyltransferase, thereby inhibites protein synthesis.Chloramphenicol is widely used to treat eye infections, is the first choice to cure conjunctivitis, keratitis, trachoma and so on. Chloramphenicol eye drops are sensitive for heat and light. Heat and light will accelerate the hydrolysis of chloramphenicol. During the sale and the transportation in hot seasons, local temperature is too high will result in rapid hydrolysis of chloramphenicol, meanwhile chloramphenicol diol materials increase significantly, thus enhancing the stability of chloramphenicol eye drops has become urgent.Hydroxypropyl-β-cyclodextrin(HP-β-CD) is hydrophilic derivatives condensed byβ-cyclodextrin((3-CD) and 1,2-propylene oxide. HP-β-CD is amorphous powder, more than 50% soluble in water, soluble in alcohol aqueous solution. HP-β-CD is relatively low renal toxicity, then it can be used for parenteral route.HP-β-CD is not hydrolyzed by acid andα-amylase,almost not appears in vivo metabolism, not accumulates, largely excreted in full form. It complexing with drugs promotes the release of the drugs in vivo. The surface activity of HP-β-CD is low, and HP-β-CD is little or no hemolytic and irritant. As a safe, stable accessories, HP-β-CD are widely used as ophthalmic drug solubilizer. Eye drops made of HP-β-CD is low viscosity, non-irritating, enhancing the corneal drug bioavailability.1. Stability test of chloramphenicol eye drops with hydroxypropyl-β-cyclodextrin According to the current problems of chloramphenicol eye drops, prescriptions were screened and suitable stabilizing agent was added to increase the stability of drug. Changing drug dosage form, taking advantage of the nature of chloramphenicol, and using independent package of solid-liquid, non-aqueous phase-aqueous phase ensure the qualification in the validity term.The preferred prescription by the screening of pharmaceutic adjuvants was identified, and the quality and stability of chloramphenicol eye drops were researched. The results showed that the products complied with the provisions of the existing quality standards after changing adjuvants and process, and chloramphenicol diol significantly reduced during the product storage.2. Study on bacteriostatic action of chloramphenicol eye drops with hydroxypropy1-β-cyclodextrinThe bacterial inhibition ring test was used to compare the bacteriostatic action of chloramphenicol-hydroxypropyl-β-cyclodextrin eye drops, chloramphenicol-sodium hyaluronate eye drops and chloramphenicol eye drops on Staphylococcus aureus and Escherichia coli. The results showed that chloramphenicol eye drops with HP-β-CD have good bacteriostatic action on Staphylococcus aureus and Escherichia coli, and by the statistics analysis there was no significant difference in bacteriostatic action of three different eye drops.Achievements of this research:(1) Several relatively stable prescriptions to improve the stability of chloramphenicol eye drops were developed.(2) The adding of HP-(3-CD not only improves the stability of chloramphenicol eye drops but also ensures its bacteriostatic action. It provides a reliable experimental basis for clinical prevention and treatment of Staphylococcus aureus and Escherichia coli, and brings a broad prospect for the development of new drugs. |
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