Fluconazole for the treatment of cutaneous leishmaniasis

Effects of fluconazole on the pharmacokinetics and pharmacodynamics of antimony in cutaneous leishmaniasis-infected hamsters

Pentavalent antimony (Sb(V)) compounds are the drugs of choice for the treatment of all forms of leishmaniasis. For 20 years there has been an interest in antifungal azoles for treating leishmaniasis, with variable success. In the current study, we examined the effects of co-administration of fluconazole (FLZ) on the pharmacokinetics and pharmacodynamics of Sb(V) in cutaneous leishmaniasis-infected hamsters. Hamsters were divided into four groups. All hamsters were injected with 0.1 mL of 1x10(8)promastigotes/mL into the right foot on Day 1. Treatment was started 5 days after the infection. The antimony group received 80 mg/kg/day of Pentostam intramuscularly whilst the FLZ group received FLZ 20 mg/kg/day orally for 14 days. The combination group received both Pentostam and FLZ at the above mentioned doses for 14 days. Animals in the control group received no treatment. The infected footpads were measured on Days 1 and 14. A pharmacokinetic study was conducted on Days 1 and 14 of treatment, representing single- and multiple-dose pharmacokinetics, respectively. Blood samples were collected at different time intervals up to 24h. Sb(V) was determined using flameless atomic absorption spectrophotometry. Pharmacokinetic parameters were calculated using a non-compartmental analysis. In the single-dose study, there was no statistically significant difference in any of the pharmacokinetic parameters of Sb(V) when given alone or with FLZ. However, on Day 14 a significant increase in peak plasma concentration (C(max)) (three-fold) and area under the concentration-time curve (AUC) (four-fold) of antimony was observed when Sb(V) was co-administered with FLZ. A statistically significant prolongation of the terminal half-life from 1.63 to 8.67 h (P<0.05) was also observed. A significant reduction in clearance was detected. However, FLZ had no effect on the pharmacodynamics of Sb(V) as measured by footpad sizes. In conclusion, FLZ did not improve the therapeutic effect of Sb(V) when given concomitantly despite the significant increase in blood concentration and prolongation of the elimination half-life of Sb(V).

Delivery strategies for antiparasitics

Optimisation of drug carrier systems and drug delivery strategies that take into account the peculiarities of individual infectious agents and diseases are key elements of modern drug development. In the following, different aspects of a rational design for antiparasitic drug formulation will be reviewed, covering delivery systems such as nano- and microparticles, liposomes, emulsions and microemulsions, cochleates and bioadhesive macromolecules. Functional properties for each carrier system will be discussed as well as their therapeutic efficacy for parasitic diseases, including leishmaniasis, human African trypanosomiasis, human cryptosporidiosis, malaria and schistosomiasis. Critical issues for the application of drug carrier systems will be discussed, focusing on biopharmaceutical and pathophysiological parameters such as routes of application, improvement of body distribution and targeting intracellularly persisting pathogens.