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Levofloxacin, the levo-isomer of the antibiotic ofloxacin, can crystallize into two different hydrate forms, the monohydrate and the hemihydrate. Although these forms are well characterized, little is known about their anhydrous structures besides the study of Singh and Thakur using crystal structure prediction. In order to solve this issue, this paper proposes the use of high-temperature powder X-ray diffraction to determine the anhydrous structures of the levofloxacin forms termed in the literature as α and γ, herein obtained by heating of the levofloxacin monohydrate and hemihydrate, respectively. These are the first levofloxacin anhydrates whose structures could be solved. To support our results, the dehydration process has been also evaluated by means of differential scanning calorimetry, thermogravimetric analysis, and hot-stage polarized microscopy. The resulting X-ray structures differ from the ones reported as the best-predicted solution, although the predicted work had predicted similar structures as lower ranked solutions.

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Background/Aim: Melanoma represents a big challenge for clinical treatment. Besides being the most aggressive and the deadliest form of skin cancer, it is often refractory to commonly used anticancer drugs. Hence, developing new anti-cancer agents is crucial to improve refractory melanoma treatment. Studies using palladium(II) complexes have reported antitumor effects on cancer cells. In this study, we aimed to determine the cytotoxic effect of three novel synthesized Pd(II) complexes with Schiff bases derived from 4-aminoacetophenone on the MDA-MB-435 melanoma cell line. Materials and Methods: Cells were treated with ligand and Pd(II) complexes. Cell viability, morphology and death induction upon treatment were examined. Results: Novel synthesized Pd(II) complexes led to decreased viability of cells. They also induced morphological alterations and cell death, mainly in the C3 complex. Conclusion: The novel synthesized complexes have a significant cytotoxic effect on cell line MDA-MB-435, especially C3 and can be considered as an antitumor agent for further studies.Cancer poses a major threat to public health worldwide, and the incidence rates have increased in most countries (1). Globally, the most frequent kind of malignancy is skin cancer, which has been categorized into non-melanoma and melanoma skin cancers. Cutaneous melanoma is the deadliest form of skin cancer, its incidence varies greatly between countries, and has been increasing at a more rapid rate than other cancer types (2).Treatment of cutaneous melanoma experienced a revolution over the past decade with the introduction of target therapy and immunotherapy. Although new therapies have achieved success in extending patient survival, most patients develop endocrine disfunctions (3) and become resistant to targeted therapy (4, 5) resulting in rapid progression with treatmentrefractory disease and once metastasized, the treatment options for melanoma become very limited (6, 7). In this scenario, chemotherapy remains important in the palliative treatment of persistent post-BRAF blockade, refractory, progressive, and relapsed melanomas (8).After the discovery of cisplatin [cis-diamminedichloroplatinum(II)], a chemotherapeutic agent widely used against several tumor types, including melanoma, antitumor metallodrugs have emerged as potential alternatives for cancer treatment. This is the case of palladium(II) complex, a structurally analog to cisplatin, with reported cytotoxic activity against various cancer cell lines and lesser toxicity to normal cells (9)(10)(11)(12)(13)(14). In this study, we synthesized novel Schiff base palladium(II) complexes derivated from 4-aminoacetophenone and evaluated their cytotoxic effects on melanoma cell line, MDA-MB-435. Materials and Methods Synthesis of imine ligands (L1-L3).A solution of p-anisaldehyde (8.28 mmol), terephthaldehyde (4.13 mmol) or trans-cinnamaldehyde (8.26 mmol) in ethanol (5 ml), was added dropwise to a solution of of 4-6693