The antineoplastic drug flavopiridol reverses memory impairment induced by Amyloid-ß1-42 oligomers in mice.

The ectopic re-activation of cell cycle in neurons is an early event in the pathogenesis of Alzheimer's disease (AD), which could lead to synaptic failure and ensuing cognitive deficits before frank neuronal death. Cytostatic drugs that act as cyclin-dependent kinase (CDK) inhibitors have been poorly investigated in animal models of AD. In the present study, we examined the effects of flavopiridol, an inhibitor of CDKs currently used as antineoplastic drug, against cell cycle reactivation and memory loss induced by intracerebroventricular injection of Aß1-42 oligomers in CD1 mice. Cycling neurons, scored as NeuN-positive cells expressing cyclin A, were found both in the frontal cortex and in the hippocampus of Aß-injected mice, paralleling memory deficits. Starting from three days after Aß injection, flavopiridol (0.5, 1 and 3mg/kg) was intraperitoneally injected daily, for eleven days. Here we show that a treatment with flavopiridol (0.5 and 1mg/kg) was able to rescue the loss of memory induced by Aß1-42, and to prevent the occurrence of ectopic cell-cycle events in the mouse frontal cortex and hippocampus. This is the first evidence that a cytostatic drug can prevent cognitive deficits in a non-transgenic animal model of AD.

Pharmacokinetics of a new subcutaneous diclofenac formulation administered to three body sites: quadriceps, gluteus, and abdomen.

OBJECTIVE: To assess the relative bioavailability of a new subcutaneous (SC) diclofenac hydroxypropyl b-cyclodextrin (HPbCD) formulation administered to three body sites: quadriceps, gluteus, and abdomen. MATERIALS AND METHODS: This was a pilot, single-dose, randomized, three-way crossover relative bioavailability study. A total of 12 healthy subjects received a single SC injection of diclofenac HPbCD 50 mg/1 mL in the quadriceps, gluteus, or abdomen. RESULTS: The AUC was comparable after SC diclofenac HPbCD in the quadriceps, gluteus, and abdomen. The Cmax was comparable after SC administration in the quadriceps or abdomen, and ~ 17% higher in the gluteus. The absorption was rapid (30 minutes) after administration of the treatment at any site. The treatment was well tolerated. CONCLUSIONS: The relative bioavailability of SC diclofenac HPbCD was comparable when administered to the quadriceps, gluteus, and abdomen. The new diclofenac formulation can therefore be administered subcutaneously to any of these sites without clinically significant differences. A further adequately powered study would be necessary to reveal any differences among injection sites in terms of peak plasma concentration.

Isoflavones: estrogenic activity, biological effect and bioavailability.

Isoflavones are phytoestrogens with potent estrogenic activity; genistein, daidzein and glycitein are the most active isoflavones found in soy beans. Phytoestrogens have similarity in structure with the human female hormone 17-ß-estradiol, which can bind to both alpha and beta estrogen receptors, and mimic the action of estrogens on target organs, thereby exerting many health benefits when used in some hormone-dependent diseases. Numerous clinical studies claim benefits of genistein and daidzein in chemoprevention of breast and prostate cancer, cardiovascular disease and osteoporosis as well as in relieving postmenopausal symptoms. The ability of isoflavones to prevent cancer and other chronic diseases largely depends on pharmacokinetic properties of these compounds, in particular absorption and distribution to the target tissue. The chemical form in which isoflavones occur is important because it influences their bioavailability and, therefore, their biological activity. Glucose-conjugated isoflavones are highly polar, water-soluble compounds. They are hardly absorbed by the intestinal epithelium and have weaker biological activities than the corresponding aglycone. Different microbial families of colon can transform glycosylated isoflavones into aglycones. Clinical studies show important differences between the aglycone and conjugated forms of genistein and daidzein. The evaluation of isoflavone metabolism and bioavailability is crucial to understanding their biological effects. Lipid-based formulations such as drug incorporation into oils, emulsions and self-microemulsifying formulations have been introduced to increase bioavailability. Complexation with cyclodextrin also represent a valid method to improve the physicochemical characteristics of these substances in order to be absorbed and distributed to target tissues. We review and discuss pharmacokinetic issues that critically influence the biological activity of isoflavones.

Long-lasting rescue of schizophrenia-relevant cognitive impairments via risperidone-loaded microPlates.

Schizophrenia is a disorder characterized by cognitive impairment and psychotic symptoms that fluctuate over time and can only be mitigated with the chronic administration of antipsychotics. Here, we propose biodegradable microPlates made of PLGA for the sustained release of risperidone over several weeks. Two microPlate configurations - short: 20 × 20 × 10 µm; tall: 20 × 20 × 20 µm - are engineered and compared to conventional ~ 10 µm PLGA microspheres in terms of risperidone loading and release. Tall microPlates realize the slowest release documenting a 35% risperidone delivery at 100 days with a residual rate of 30 ng/ml. Short microPlates and microspheres present similar release profiles with over 50% of the loaded risperidone delivered within the first 40 days. Then, the therapeutic efficacy of one single intraperitoneal injection of risperidone microPlates is compared to the daily administration of free risperidone in heterozygous knockout mice for dysbindin-1, a clinically relevant mouse model of cognitive and psychiatric liability. In temporal order object recognition tasks, mice treated with risperidone microPlates outperform those receiving free risperidone up to 2, 4, 8, and 12 weeks of observation. This suggests that the sustained release of antipsychotics from one-time microPlate deposition can rescue cognitive impairment in dysbindin mice for up to several weeks. Overall, these results demonstrate that risperidone-loaded microPlates are a promising platform for improving cognitive symptoms associated to schizophrenia. Moreover, the long-term efficacy with one single administration could be of clinical relevance in terms of patient's compliance and adherence to the treatment regimen. Single injection of long-acting risperidone-loaded µPL ameliorates the dysbindin-induced deficit in a clinically relevant mouse model of cognitive and psychiatric liability for up to 12 weeks.

Human pharmacokinetics of the muscle relaxant, eperisone hydrochloride by liquid chromatography-electrospray tandem mass spectrometry.

Eperisone hydrochloride (4'-ethyl-2-methyl-3-piperidinopropiophenone hydrochloride) is a muscle relaxant agent, widely used in the treatment of patients with muscular contractures, low back pain or spasticity. Because of its mechanism of action (inhibition of gamma-efferent firing and local vasodilatation activity), side effects on central nervous system are rarely observed. A sensitive liquid chromatography-electrospray ionization-mass spectrometry method for determination of eperisone in human plasma has been developed, with a lower limit of quantification of 0.01 ng/mL. The method was applied to a pharmacokinetic study in 12 healthy volunteers given eperisone 100 mg as single dose on day 1 and three times daily on days 2 to 4. Eperisone was rapidly absorbed after oral administration (T (max) = 1.6 h) as it was expected by its fast-onset relaxant activity. Moreover, eperisone underwent a rapid elimination from the body (biological half-life 1.87 h), which was not modified during the repeated dosing as suggested by the C (max) cumulation observed, not different from that expected for a t (1/2) of 1.87 h as suggested by the similar and negligible plasma concentration values (0.063 and 0.067 ng/mL) measured on day 4 before the morning dose and 12 h after evening dose, thus ruling out any potential risk for drug accumulation. Thus, the pharmacokinetic characteristics of eperisone provide further justification for its tolerability in patients with low back pain or spastic palsy, in which the drug is given for periods ranging from few days to several months, respectively.

Ocular Pharmacological Profile of Hydrocortisone in Dry Eye Disease.

To investigate the ocular pharmacological profile of hydrocortisone (HC) using in vitro and in vivo models of dry eye disease. Rabbit corneal epithelial cells (SIRCs) were used to assess the effect of HC in two paradigms of corneal damage: hyperosmotic stress and scratch-wound assay. Dry eye was induced in albino rabbits by topical administration of atropine sulfate or by injection of concanavalin A (ConA) into the lacrimal gland. TNFα, TNF-related apoptosis-inducing ligand (TRAIL), IL-1ß, and IL-8 were determined by ELISA or western blot in a corneal damage hyperosmotic in vitro model, with or without HC treatment. Inflammatory biomarkers, such as TNFα, IL-8, and MMP-9, were evaluated in tears of rabbit eye injected with ConA and treated with HC. Tear volume and tear film integrity, in both in vivo models, were evaluated by the Schirmer test and tear break-up time (TBUT). Ocular distribution of four formulations containing HC (0.001%, 0.003%, 0.005%, and 0.33%) was performed in the rabbit eye. Aqueous humor samples were collected after 15, 30, 60, and 90 min from instillation and then detected by LC-MS/MS. Hyperosmotic insult significantly activated protein expression of inflammatory biomarkers, which were significantly modulated by HC treatment. HC significantly enhanced the re-epithelialization of scratched SIRCs. Treatment with HC eye drops significantly reduced the tear concentrations of TNF-α, IL-8, and MMP-9 vs. vehicle in the ConA dry eye model. Moreover, HC significantly restored the tear volume and tear film integrity to levels of the control eyes, both in ConA- and atropine-induced dry eye paradigms. Finally, we demonstrated that HC crossed, in a dose-dependent manner, the corneal barrier when the eyes were topically treated with HC formulations (dose range 0.003-0.33%). No trace of HC was detected in the aqueous humor after ocular administration of eye drops containing the lowest dose of the drug (0.001%), indicating that, at this very low concentration, the drug did not pass the corneal barrier avoiding potential side effects such as intraocular pressure rise. Altogether, these data suggest that HC, at very low concentrations, has an important anti-inflammatory effect both in vitro and in vivo dry eye paradigms and a good safety profile.

Retinal Protection and Distribution of Curcumin in Vitro and in Vivo.

Diabetic retinopathy (DR), a secondary complication of diabetes, is a leading cause of irreversible blindness accounting for 5% of world blindness cases in working age. Oxidative stress and inflammation are considered causes of DR. Curcumin, a product with anti-oxidant and anti-inflammatory properties, is currently proposed as oral supplementation therapy for retinal degenerative diseases, including DR. In this study we predicted the pharmacodynamic profile of curcumin through an in silico approach. Furthermore, we tested the anti-oxidant and anti-inflammatory activity of curcumin on human retinal pigmented epithelial cells exposed to oxidative stress, human retinal endothelial and human retinal pericytes (HRPCs) cultured with high glucose. Because currently marketed curcumin nutraceutical products have not been so far evaluated for their ocular bioavailability; we assessed retinal distribution of curcumin, following oral administration, in rabbit eye. Curcumin (10 µM) decreased significantly (p < 0.01) ROS concentration and TNF-α release in retinal pigmented epithelial cells and retinal endothelial cells, respectively. The same curcumin concentration significantly (p < 0.01) protected retinal pericytes from high glucose damage as assessed by cell viability and LDH release. Among the tested formulations, only that containing a hydrophilic carrier provided therapeutic levels of curcumin in rabbit retina. In conclusion, our data suggest that curcumin, when properly formulated, may be of value in clinical practice to manage retinal diseases.

Influence of inulin on plasma isoflavone concentrations in healthy postmenopausal women.

BACKGROUND: Bacterial intestinal glucosidases exert an important role in isoflavone absorption. Insoluble dietary fibers such as inulin may stimulate the growth of these bacteria in the colon and, hence, stimulate the absorption of these substances in subjects who may need isoflavone supplementation. OBJECTIVE: The objective was to assess the influence of inulin on plasma isoflavone concentrations after intake of soybean isoflavones in healthy postmenopausal women. DESIGN: Twelve healthy postmenopausal women participated in a randomized, double-blind, crossover study. They consumed 40 mg of a conjugated form of soybean isoflavones (6 mg daidzein and 18 mg genistein as free form) with or without 3.66 g inulin twice daily in two 21-d experimental phases. Blood samples were collected 0, 1, 2, 3, 4, 6, 10, 12, and 24 h after intake of isoflavones with breakfast and dinner at the end of each 21-d experimental phase. Plasma concentrations of isoflavones were assessed by HPLC with an electrochemical detector. RESULTS: Plasma 24-h areas under the curve indicated that the intake of soybean isoflavones with inulin for 21 d was followed by higher plasma concentrations of daidzein and genistein (38% and 91%, respectively) compared with the formulation without inulin. Furthermore, the time for the maximum concentration of daidzein and genistein appeared to be lower after the 21-d intake of soybean isoflavones, with or without inulin. However, the time for the maximum concentration of daidzein and genistein after supplementation with the inulin-containing formulation on day 21 was not significantly different from that after supplementation with the formulation without inulin. CONCLUSIONS: Inulin may increase the apparent plasma concentrations of the soybean isoflavones daidzein and genistein in postmenopausal women. The higher plasma concentrations of the 2 isoflavones suggests that the absorption of each was facilitated by the presence of inulin.

Pharmacokinetic characterization of tizanidine nasal spray, a novel intranasal delivery method for the treatment of skeletal muscle spasm.

BACKGROUND AND OBJECTIVE: The skeletal muscle relaxant tizanidine is approved by the US FDA and the European Medicines Agency for treating spasticity and is supplied as tablets for oral administration. However, tizanidine has a poor bioavailability, due to extensive first-pass metabolism. Therefore, the nasal route of administration, which bypasses portal circulation, may increase the bioavailability of tizanidine and, possibly, reduce the time to peak plasma concentration, thereby shorting the latency of therapeutic effect. The objective of this study was to evaluate the pharmacokinetic profile of tizanidine nasal spray and compare it to the profile of tizanidine oral tablets. METHODS: This open-label, phase I study comprised two protocols: protocol 1, tizanidine HCl solution (32.73 mg/mL) intranasally at single doses of 2 and 4 mg versus 4 mg tizanidine oral tablets (randomized, three periods crossover, 12 healthy subjects); and protocol 2, tizanidine HCl solution (16.36 mg/mL) intranasally at a single dose of 1 mg vs. 4 mg tizanidine oral tablets (randomized, two periods crossover, 12 healthy subjects, one dropout). Tizanidine plasma concentrations were determined by liquid chromatography/mass spectrometry. RESULTS: There was a linear relationship between different dosages of intranasal formulation and the area under the concentration-time curve and maximum plasma concentration (C(max)). The relative bioavailability of the different dosages of intranasal formulation were 1.29, 1.93, and 4.23 for 1, 2, and 4 mg intranasal administration, respectively. Comparison of C(max) values gave the following ratios: 0.91, 1.39, and 2.73, for 1, 2, and 4 mg intranasal administration, respectively. The mean time to C(max) (t(max)) was 0.99, 0.43, and 0.63 h for 1, 2, and 4 mg intranasal administration, respectively, whereas it was 1.13 and 1.30 h for the two series of 4 mg tizanidine oral tablets. CONCLUSIONS: The bioavailability of the tizanidine intranasal formulation was higher than that of tizanidine oral tablets. The t(max) was also shorter with the intranasal formulation. No serious adverse events occurred throughout the study, such that the two formulations resulted equally well-tolerated. The intranasal formulation of tizanidine results are therefore worthy of subsequent clinical testing in phase II.

Efficacy of adipose tissue-mesenchymal stem cell transplantation in rats with acetaminophen liver injury.

OBJECTIVE: Acetaminophen intoxication is a leading cause of acute liver failure. Liver transplantation for acute liver failure is limited by the availability of donor organs. In this study, we aimed at identifying if the transplantation of adipose tissue-mesenchymal stem cells (ASCs) may exert therapeutic effects on acetaminophen-induced liver injury. METHODS: ASCs were isolated from human subcutaneous tissue and were transfected with a green fluorescent protein (GFP). Sprague-Dawley rats were administrated 300mg/kg of acetaminophen intraperitoneally and were transplanted with ASCs or vehicle. After 24h from acetaminophen administration, rats were sacrificed. Hepatic levels of isoprostanes, 8-hydroxyguanosine (8-OHG), nitrites/nitrates and reduced glutathione (GSH) were determined as markers of oxidative stress; JNK phosphorylation and hepatic levels of inflammatory cytokines and regeneration factors were also assessed. RESULTS: Transplantation of ASCs decreased AST, ALT and prothrombin time to the levels observed in control rats. Transplanted animals had normal plasma ammonia and did not display clinical encephalopathy. Liver sections of intoxicated rats treated with vehicle showed lobular necrosis and diffuse vacuolar degeneration; in rats transplanted with ASCs liver injury was almost absent. Transplantation of ASCs decreased liver isoprostanes, 8-OHG and nitrite-nitrates to the levels of control rats, while preserving GSH. Consistently, hepatic levels of TNF-α, MCP-1, IL-1ß, ICAM-1 and phospho-JNK were markedly increased in rats treated with vehicle and were restored to the levels of controls in animals transplanted with ASCs. Furthermore, ASC transplantation increased liver expression of cyclin D1 and PCNA, two established hepatocyte regeneration factors, whereas ASCs were not able to metabolize acetaminophen in vitro. CONCLUSION: In this study, we demonstrated that ASC transplantation is effective in treating acetaminophen liver injury by enhancing hepatocyte regeneration and inhibiting liver stress and inflammatory signaling.

Ocular pharmacokinetics profile of different indomethacin topical formulations.

PURPOSE: This study evaluated the ocular pharmacokinetics of indomethacin following topical administration of two different formulations present in the market. METHODS: Rabbits received a multiple topical instillation (30 µL) of indomethacin ophthalmic suspension containing hydroxypropylmethylcellulose (IND-HPMC; Indom™ Alfa-Intes) or indomethacin ophthalmic solution with hydroxypropyl-ß-cyclodextrin (IND-CD; Indocollirio™ Bausch & Lomb). Aqueous humor, vitreous humor, and retina were collected from animals at fixed time intervals after dosing. Indomethacin ocular levels were measured by liquid chromatography mass spectrometry (LC-MS/MS), and the pharmacokinetic parameters--peak drug concentration (C(max)), time to peak value (T(max)), and area under the concentration-time curve between 0 and 240 min (AUC(0-240))--were determined. All of the animals were treated according to the Association for Research in Vision and Ophthalmology (ARVO) Statement for the Use of Animals in Ophthalmic and Vision Research. RESULTS: Peak concentrations of indomethacin in aqueous and vitreous were achieved within 30 min and 60 min after a single instillation of IND-HPMC and IND-CD, respectively. Retinal T(max) was 30 min and 120 min in the IND-HPMC-treated group and the IND-CD-treated group, respectively. Higher levels of indomethacin were found in retina after IND-HPMC administration compared to IND-CD (AUC(0-240) 272.9 ng/g per min vs. AUC(0-240) 73.5 ng/g/min, respectively; P<0.01). Also in the aqueous and vitreous, the drug levels were statistically higher (P<0.01) in the IND-HPMC group in comparison with the IND-CD group (AUC(0-240) 2039 ng/mL per min vs. AUC(0-240) 427.3 ng/mL per min, AUC(0-240) 53.8 ng/mL per min vs. AUC(0-240) 12.5 ng/mL per min, respectively). The highest drug levels in the ocular tissues were found following IND-HPMC administration compared with IND-CD (retina: C(max) 73.7±6.4 ng/g vs. 25.5±1.73 ng/g; aqueous: C(max) 952±6.8 ng/mL vs. 163±4.1 ng/mL; vitreous C(max) 31±3.5 ng/mL vs. 6.37±3.6 ng/mL). CONCLUSIONS: IND-HPMC treatment demonstrates a nonclinical ocular pharmacokinetic profile of indomethacin characterized by higher concentrations of drug in ocular tissues (4.7-, 4.3- and 3.7-fold higher in aqueous, vitreous, and retina, respectively) compared to the ND-CD-treated group. Taken together, these data seem to indicate that IND-HPMC formulation has good ocular distribution reaching relevant indomethacin levels in the back of the eye, and suggest that this formulation may be very useful for clinicians to manage retinal conditions.