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Pre-Clinical Evaluation of Antifungals

In vitro pre-clinical evaluation

In vivo pre-clinical evaluation (Animal Models)

The discovery of a new drug is followed by its screening for its antifungal activity. Even with successful drugs, the possibility of resistance development is a important question. This question can be answered by us using our antifungal susceptibility testing methods. These methods are now the standard in determining the Minimum Inhibitory Concentration (MIC) and Minimum Cidal Concentration (MCC) for antifungals. Evaluation of drug efficacy and resistance in vivo is the next logical step, which we perform by testing the antifungal in animal models.

We have established infra-structure supported by competent staff to conduct both in vitro as well as in vivo evaluation of new antifungals before their introduction into the clinical setup.

We can help you if you are a pharmaceutical/biotech company (a) with new antifungals, (b) developing successful antifungals, and/or (c) synthesizing novel compounds with possible antifungal activity.

If you are a pharmaceutical/biotech company developing new antifungals, we can chip in with our expertise in pre-clinical evaluation of antifungals for their efficacy against a wide range of fungi including Candida albicans, Cryptococcus neoformans, dermatophytes, etc. We have an extensive collection of fungi isolated from patients. We routinely check the spectrum of antifungal efficacy against these fungal strains.

If you are a pharmaceutical company with successful antifungals in the market, you might be interested in knowing the patterns of resistance, toxicity, specificity of your compound. We will be more than willing to help you out in these areas too, as we have a wide variety of facilities available at our disposal to conduct these tests.

Studies on pharmacokinetics of antifungal drugs are done routinely by us - these studies compliment the cytotoxicity studies.

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In vitro pre-clinical evaluation

Slide show of antifungal susceptibility testing methods.

We provide the following studies for in vitro pre-clinical evaluation of antifungals:

  • Initial determination of general antifungal activity.
  • Spectrum of antifungal activity (MIC & MCC Studies).  For these studies we employ a large number of clinical isolates including: fluconazole-resistant and fluconazole-sensitive Candida albicans, C. glabrata, C. tropicalis, and C. krusei.  In addition, we run a spectrum of activity tests against Cryptococcus neoformans and dermatophytes.
  • Evaluation of combinations of antifungals.
  • Growth inhibition, and morphology investigations.
  • Influence of antifungal agents on the sterol and lipids of fungi.
  • Red blood cell hemolysis assay (cytotoxicity).
  • Effect of antifungal agents on the virulence factors of Candida albicans. Factors tested include germination, adherence to epithelial cells and endothelial cells, proteinase and phospholipase production, and damage to endothelial cells.
  • Antifungal drug screening facility for the preclinical evaluation of new antifungals.
  • Drug interaction studies.

We have developed standard methods for antifungal susceptibility testing of dermatophytes. To date, both of these areas have received little or no attention even though infections with these agents are increasing and may cause devastating systemic infections in the immunocompromised host, especially in those whose neutrophil and macrophage functions is deficient.

Of particular relevance in the clinical laboratory area is the microdilution method we developed for determining the susceptibility of Cryptococcus neoformans. We have shown that this method is reproducible, easy to perform and has both intra- and inter-laboratory agreement. Critically, we demonstrated that cryptococcal susceptibility to fluconazole is an important predictor of treatment success for patients with acute AIDS-associated cryptococcal meningitis. This method was adopted as part of the NCCLS Reference Method for Antifungal Susceptibility Testing. Developing a susceptibility method for dermatophytes is currently being performed at CMM.

Click here for a slide show of antifungal susceptibility testing methods.

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In vivo pre-clinical evaluation (Animal Models)*

We have developed a number of animal models for the evaluation of antifungal efficacy.  These models have been time-tested for their reliance and have been supported by research experiments. Results of these experiments have been reported in widely-circulated journals. (A copy of the references can be provided on request)

Candidiasis: Murine and Rabbit Models

X-ray of catheterized rabbit.

  • Immunocompetent murine model of hematogenously disseminated candidiasis,
  • Neutropenic murine model of hematogenously disseminated candidiasis,


Candidiasis: Guinea Pig Model

X-ray of catheterized guinea pig viewed from (A) bottom, and (B) side.

  • Neutropenic guinea pig model for determining the efficacy of antifungals against a hematogenously disseminated infection caused by Candida glabrata and the fluconazole-resistant Candida krusei.


Cryptococcosis: Murine Model Intra-cranial murine model of acute cryptococcal meningitis

We have developed a highly reproducible intracranial murine model of cryptococcosis using Balb/c mice. Mice are challenged intracranially and treated with different drugs administered singly or in combination. Survival and brain CFU analyses are performed. Effect of drug prophylaxis is also determined. The developed in vivo model mimics clinical signs of cryptococcal meningitis. An abstract of this article can be viewed in J Chemother. 2002 Aug;14(4):351-60.

 

Dermatophytes: Guinea Pig Model

*All animal models have been developed according to the guidelines outlined in the Institutional Review Board (IRB) specifications for research studies involving animal subjects. All animals are housed in the in-house Animal Research Center (ARC), supported by excellent, round-the-clock care and maintenance by the ARC staff.

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