Fibrin gels loaded with cisplatin and cisplatin-hyaluronate complexes tested in a subcutaneous human melanoma model.

Fibrin gels are attractive biomaterials for local delivery of a variety of agents, from drugs to proteins. Similarly, polymer-anticancer-drug conjugates and nanoparticles are emerging as potential candidates for cancer treatment. Combining these different approaches, we have studied the efficacy of fibrin gels loaded with cisplatin (DDP) and a complex of DDP with hyaluronate (DDP-HA) for tumor growth inhibition in a melanoma model. Loaded gels prepared at relatively high fibrinogen concentration (22 mg/ml) showed good in vitro antiproliferative activities, prolonged release of the anticancer drug, and a long persistence (10-15 days) in vivo when implanted subcutaneously (sc) in immunodeficient mice. Gels loaded with DDP or DDP-HA containing 1/3 or even 1/6 of their systemic dose (6 mg/kg) and positioned under the tumor mass in mice bearing a sc human SK-Mel-28 tumor showed an antitumor activity better than that of the original parent compound given intraperitoneally (ip). Moreover, in an additional experiment in vivo, fibrin gels loaded with N-trimethyl chitosan-based nanoparticles containing a DDP-HA complex were assayed, resulting in a further 8 % improvement of anticancer activity, with lesser adverse systemic toxic effects. Taken together, these results suggest that the combination of fibrin gels and drugs complexed with suitable macromolecules holds great promise for loco-regional anticancer therapy of melanoma and other surgically removable cancer types.

A chitosan lactate/poloxamer 407-based matrix containing Eudragit RS microparticles for vaginal delivery of econazole: design and in vitro evaluation.

A matrix based on chitosan lactate and poloxamer 407 was evaluated as a delivery system for the vaginal administration of the antifungal drug econazole. The matrix was investigated both containing the pure drug and after introducing microparticles of Eudragit RS 100 containing econazole. Eudragit RS 100 microparticles were prepared using an emulsion-extraction method and dispersed in a solution containing chitosan lactate (2% w/w) and poloxamer 407 (1.7% w/w). The microparticles, obtained with a yield of 64% w/w and an encapsulation efficiency of 42% w/w, had a diameter of less than 2 µm and a drug loading of 13% w/w. The compressed matrices, characterized by DSC, swelling, erosion, release and mucoadhesion studies, had behaviours dependent on the relative amounts of the contained microparticles. The matrix without microparticles (MECN) showed zero-order release kinetics, with a maximum drug-release of 60% w/w, while those containing 50 or 75% w/w microparticles showed a diffusion controlled release up to 8 and 16 h, respectively, and a linear trend after those time intervals, caused by the erosion process, which allowed reaching a drug-release of approximately 100% w/w at 22 h. In in vitro experiments, the matrices were mucoadhesive and active in inhibiting the growth of Candida albicans 796.

Preparation, characterisation and preliminary antitumour activity evaluation of a novel nanoparticulate system based on a cisplatin-hyaluronate complex and N-trimethyl chitosan.

In this work, nanoparticles with a positive surface charge were prepared through the electrostatic interaction of a new cisplatin-hyaluronate complex with N-trimethyl chitosan (substitution degree of 85%). Mean particle diameter was approximately 195 nm. Drug loading of nanoparticles, which had a zeta potential of about 27 mV, was equal to 6% w/w. After 24 h, while the cisplatin-hyaluronate complex released approximately 60% w/w drug in phosphate buffered saline at pH 7.4, approximately 40% w/w of total cisplatin was released from nanoparticles. The same cumulative amounts of released drug were found after 48 h. These nanoparticles, as well as the starting cisplatin-hyaluronate complex, were active on all cell lines tested (P388, A2780, A549), with an antiproliferative activity similar to that of cisplatin. Apoptosis was markedly induced in A2780 cells by nanoparticles. In a preliminary in vivo experiment, the antitumour activity against a murine tumour (P388 cells) subcutaneously implanted in mice, resulted similar to that of cisplatin for nanoparticles whereas the starting complex showed a non-significant activity at the cisplatin dose tested. Body weight change of treated mice suggested a significantly better tolerance of the nanoparticles compared to cisplatin, after an initial brief period of acute toxicity higher than the parent drug. These results indicate that such a particulate system could be useful as a carrier for cisplatin delivery.

Study of retinoic acid polymorphism.

Some authors recently hypothesized the existence of a new retinoic acid (RA) phase in addition to the two already known polymorphs. We investigated RA polymorphism and our results exclude the presence of new modifications and refine the properties of the known forms. By comparison of simulated and acquired X-Ray Powder Diffraction (XRPD) it was possible to identify only the known monoclinic (I) and the triclinic (II) modifications; the same were also characterized by DSC, IR, and Raman spectroscopy. A solubility study associated to DSC allowed establishing an enantiotropic relationship between the two forms, with form II being less stable (DeltaGII/I=0.71 kJ/mol at 37 degrees C) below the transition temperature (136.6 degrees C; DeltaH=3.2 kJ/mol). The intrinsic dissolution rate (IDR) (I=61 microg/cm2xmin-1; II=125 microg/cm2xmin-1) confirmed this energetic relationship. The kinetics of solid transition I-->II was examined and its activation energy estimated (356 kJ/mol). The attempts to produce new phases allowed the development of methods to obtain the two polymorphs with high chemical and polymorphic purity. A validated DSC method is presented that enables detection of the presence of form I at a level of 1% (w/w) when in mixture with form II.

Morphological and histochemical evidence of the protective effect of procainamide hydrochloride on tissue damage induced by repeated administration of low doses of cisplatin.

BACKGROUND: The class 1 antiarrhythmic drug procainamide hydrochloride might protect against acute cisplatin-induced nephrotoxicity and hepatotoxicity in mice and rats. In this report, the protective activity of procainamide hydrochloride against renal and hepatic tissue damage induced by repeated administration of low doses of cisplatin was analyzed morphologically and histochemically. MATERIALS AND METHODS: Light microscopy observations were performed on liver, renal and heart samples obtained from female Wistar rats treated twice a week for 10 weeks with 1 mg/kg cisplatin (cumulative dose: 20 mg/kg), with or without 100 mg/kg procainamide hydrochloride (cumulative dose: 2 g). Samples were then submitted to histochemical stainings [i.e. H & E, periodic acid Schiff (PAS) and Sudan Black]. RESULTS: Light microscopy analysis revealed that the coadministration of cisplatin and procainamide hydrochloride significantly reduced tissue alterations both in the kidneys and liver, while in the heart, neither cisplatin nor the combination of cisplatin and procainamide hydrochloride caused any evident tissue damage. CONCLUSION: The morphological and histochemical data confirm that procainamide hydrochloride is able to protect not only from acute cisplatin-induced toxicities, but also from tissue alterations induced in the liver and kidneys by the administration of repeated low doses of cisplatin.

Reduction of cisplatin hepatotoxicity by procainamide hydrochloride in rats.

In preceding papers, we proposed that procainamide hydrochloride, a class I antiarrhythmic agent, was able to protect mice and rats from cisplatin-induced nephrotoxicity and that it could exert its action through accumulation in kidneys followed by coordination with cisplatin (or its hydrolysis metabolites) and formation of a less toxic platinum compound similar to the new platinum(II) triamine complex cis-diamminechloro-[2-(diethylamino)ethyl 4-amino-benzoate, N4]-chlorideplatinum(II) monohydrochloride monohydrate, obtained by the reaction of cisplatin with procaine hydrochloride. Hepatotoxicity is not considered as a dose-limiting toxicity for cisplatin, but liver toxicity can occur when the antineoplastic drug is administered at high doses. Here, we report that procainamide hydrochloride, at an i.p. dose of 100 mg/kg, reduces cisplatin-induced hepatotoxicity, as evidenced by the normalization of plasma activity of glutamic oxalacetic transaminase and gamma-glutamyl transpeptidase, as well as by histological examination of the liver tissue. Twenty-four hours after i.p. treatment with the combination of 7.5 mg/kg cisplatin and 100 mg/kg procainamide, a significant increase of procainamide (+56%, P<0.05), total platinum (+31%, P<0.05), platinum-DNA adducts (+31%, P<0.05) and percent DNA-DNA interstrand cross-links (+69%, P<0.02) was found in liver tissue, as compared to animals treated with cisplatin alone. Moreover, in accordance with these findings, we also observed a slightly lower concentration and cumulative excretion of platinum in the feces. Since mitochondrial injury is considered a central event in the early stages of the nephrotoxic effect of cisplatin, the distribution of platinum in these subcellular organelles obtained from hepatocytes was determined after treatment with cisplatin with or without procainamide hydrochloride, together with platinum concentration in their cytosolic fraction. Our data show that the coadministration of procainamide hydrochloride produced a rearrangement of subcellular platinum distribution in hepatocytes with a slight decrease in mitochondria (-15%, P<0.10) and a slight increase in the cytosolic fraction (+40%, P<0.10) of platinum content, compared to the treatment with cisplatin alone. In analogy with our previous results in the kidney, confirmed here by our data in vitro, we suggest that the hepatoprotective activity of procainamide hydrochloride is linked to the formation of a less toxic platinum complex, which leads to inactivation of cisplatin itself and/or its highly toxic hydrolysis metabolites and to a different subcellular distribution of platinum.

Pharmacokinetic and pharmacodynamic analysis of platinum after combined treatment of cisplatin and procainamide hydrochloride in mice bearing P388 leukemia.

BACKGROUND: Our previous studies showed that procainamide hydrochloride may be an important modulator of cisplatin toxicity and antitumour activity. This study was performed in order to investigate if procainamide hydrochloride may influence the therapeutic index of cisplatin by inducing modifications of its pharmacokinetics and pharmacodymanics in vivo. MATERIALS AND METHODS: The pharmacokinetic profile of cisplatin administered either in the presence or absence of procainamide hydrochloride was investigated in BDF1 female mice bearing 6-day P388 leukemia. Procainamide hydrochloride was administered i.v. at the dose of 50 mg/kg, immediately before cisplatin which, in turn, was administered i.p. at the dose of 8 mg/kg. RESULTS: The combined administration of the antiarrhythmic drug and cisplatin caused significant differences in the pharmacokinetic profiles of Pt in plasma, ascites fluid and tissues. Filterable Pt was significantly increased both in plasma and ascites fluid in animals given the combined treatment. Similarly, a small increase was also found for total plasma Pt. These differences caused some changes of the pharmacokinetic parameters of filterable (plasma: AUC0-1 h = +16%, t1/2 alpha = +29%, t1/2b = +14%, K2p = -32%; ascites fluid: AUC0-1 h = +23%, t1/2 alpha = +78%, t1/2 beta = -49%, and total Pt (plasma: AUC0-1 h = +19%, t1/2 alpha = +27%, t1/2 beta = -22%; ascites fluid: AUC0-1 h = +6%, AUC0-infinity = +43%, t1/2 alpha = +30%). The analysis of tissue Pt content showed the general increase of Pt concentration in the main organs of animals treated with cisplatin and procainamide hydrochloride, with AUC0-24 h increased by 95%, 22%, 90% and 28% in kidney, liver, spleen and lung, respectively. The analysis of binding of Pt to DNA and percent interstrand cross-links (%ISCL) in P388 tumour cells showed that the % ISCL (10.44 +/- 3.81% vs. 3.51 +/- 0.01%) and the efficiency of ISCL formation (0.51 +/- 0.14 vs. 0.17 +/- 0.02 %ISCL.microgram DNA/pg Pt) were significantly greater when cisplatin was administered in association with procainamide hydrochloride. CONCLUSION: Our results show that procainamide hydrochloride may alter the pharmacodynamics and the pharmacokinetics and distribution of Pt in tumored mice treated with cisplatin.

Phytotoxic clerodane diterpenes from Salvia miniata Fernald (Lamiaceae).

Our ongoing research to identify natural growth inhibitors with diterpene and triterpene skeletons exuding from the surface of the aerial parts of Salvia species led us to study Salvia miniata Fernald. Ten clerodane diterpenoids were found, along with three known diterpenes. Most of the isolated compounds from S. miniata inhibited the germination of Papaver rhoeas L. and Avena sativa L. in Petri dish experiments. Parallel results have been obtained in experiments carried out to evaluate the subsequent growth of the seedlings of the target species in the presence of the tested compounds.

Antimicrobial activity of the ornamental species Salvia corrugata, a potential new crop for extractive purposes.

As a part of our search for biologically active compounds from cultivated Salvia spp. we investigated Salvia corrugata Vahl. The activity of two isolated icetaxane diterpene quinones, fruticuline A and demethylfruticuline A, was assessed against 46 bacterial pathogens, mostly resistant to several primary antibiotics. The MIC for all the inhibited Gram-positive pathogens tested showed a very narrow distribution and ranged from 32 to 64 mg/L, regardless of their resistance patterns to other antibiotics. Demethylfruticuline A was shown to be highly bactericidal (>3 log(10) CFU decrease within 24 h) against Staphylococcus aureus and S. epidermidis and bacteriostatic against Enterococcus faecalis and E. faecium. Fruticuline A manifested bacteriostatic activity against all tested strains. S. corrugata can be viewed as an interesting source for these diterpenes, which, if well tolerated in vivo, may represent new medical agents useful for the treatment of serious infections caused by resistant Gram-positive pathogens.

Inhibition of cell growth, induction of apoptosis and mechanism of action of the novel platinum compound cis-diaminechloro-[2-(diethylamino) ethyl 4-amino-benzoate, N(4)]-chloride platinum (II) monohydrochloride monohydrate.

Cis-diaminechloro-[2-(diethylamino) ethyl 4-amino-benzoate, N(4)]-chloride platinum (II) monohydrochloride monohydrate (DPR) is a new platinum triamine complex obtained from the synthesis of cisplatin and procaine. In this paper we analyzed, adopting a disease-oriented strategy, the tumour selectivity of this compound, its ability to induce apoptosis and its mechanism of interaction with DNA. The inhibition of cell proliferation was evaluated by the MTT assay using a panel of 51 tumour cell lines. Some of them were also evaluated for the induction of apoptosis by 4'-6-diamidine-2'-phenylindole (DAPI) staining, Western blot of p53 protein and agarose gel electrophoresis of ladder DNA. Finally, interstand cross-links (ISCL) were evaluated by ethidium bromide fluorescence technique. When evaluated by the MTT assay, DPR showed a high selective activity for neuroblastoma, small cell lung cancer (SCLC), ovarian cancer and leukemia cell lines. The comparison of mean graphs of DPR and cisplatin suggested that our compound possesses a mechanism of action similar to that, at least in part, of its parent compound. Moreover, DPR showed itself to be a good trigger of programmed cell death, as demonstrated by DAPI staining, activation of p53 protein and agarose gel electrophoresis of ladder DNA. Finally, the study of the formation of ISCLs demonstrated that DPR, despite being a monofunctional platinum compound, is able to form bifunctional adducts through the release of procaine residue. Data presented here suggest that DPR is an antitumour agent able to trigger apoptosis, and that it is endowed with a peculiar mechanism(s) of action and a special selective activity against two tumours, namely neuroblastoma and SCLC, which are still characterized by a low incidence of long-term survivors.