Nevirapine (C 15 H 14 N 4 O) is a lipophilic drug of low aqueous solubility used in AIDS treatment. Three different crystal forms of this non-nucleoside reverse transcriptase inhibitor were obtained after recrystallization procedures. Physical characterization was evaluated with DSC, TG, IR spectroscopy, and X-ray diffraction methods. Two new pseudopolymorphs have been characterized: nevirapine hemihydrate and nevirapine hemiethyl acetate. The pseudopolymorph identified as the hemiethyl acetate is disordered. It is converted to the hemihydrate form at room temperature. The crystal structures of the hemihydrate and hemiethyl acetate forms have been determined. The hemihydrate crystallizes in space group P2 1 /n, while the ethyl acetate form is in space group P1 h. Polymorphs and pseudopolymorphs of a drug may exhibit different chemical and physical properties, which can affect dissolution, besides manufacturing, stability, and bioavailability. For this reason, an investigation on the behavior of the two nevirapine pseudopolymorphs through the dissolution test has been described. The disk intrinsic dissolution rate of the solvent-free form has been found to be 1.5-fold greater than the hemihydrate form in 0.01 mol L -1 HCl and in 0.1 mol L -1 HCl, which can be explained by solubility results.

Context: Methotrexate (MTX) is used in the treatment of malignancies; however, its clinical application is limited by its toxic dose-related side effects. An alternative to overcome the toxicity of the MTX in healthy tissues is the design of an implantable device capable of controlling the delivery of this drug for an extended period within the tumor site. Objective: To develop methotrexate-loaded poly("-caprolactone) implants (MTX PCL implants) and to demonstrate their efficacy as local drug delivery systems capable of inhibiting Ehrlich solid tumor bearing mice. Materials and methods: MTX PCL implants were produced by the melt-molding technique and were characterized by FTIR, WAXS, DSC and SEM. The in vitro and in vivo release of MTX from the PCL implants was also evaluated. The efficacy of implants in inhibiting tumor cells in culture and the solid tumor in a murine model was revealed. Results and discussion: The chemical and morphological integrity of the drug was preserved into the polymeric matrix. The in vitro and in vivo release processes of the MTX from the PCL implants were modulated by diffusion. MTX diffused from the implants revealed an antiproliferative effect on tumor cells. Finally, MTX controlled and sustained released from the polymeric implants efficiently reduced 42.7% of the solid tumor in mice paw. Conclusion: These implantable devices represented a contribution to improve the efficacy and safety of chemotherapy treatments, promoting long-term local drug accumulation in the targeted site.

No abstract