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Integrins α4β1/ α9β1 are important in the pathogenesis and progression of inflammatory and autoimmune diseases by their roles in leukocyte activation and trafficking. Natalizumab, a monoclonal antibody selectively targeting α4β1 integrin and blocking leukocyte trafficking to the central nervous system, is an immunotherapy for multiple sclerosis (MS). However, due to its adverse effects associated with chronic treatment, alternative strategies using small peptide mimetic inhibitors are being sought. In the present study, we synthesized and characterized visabron c (4–4), a backbone cyclic octapeptide based on the sequence TMLD, a non-RGD unique α4β1 integrin recognition sequence motif derived from visabres, a proteinous disintegrin from the viper venom. Visabron c (4–4) was selected from a minilibrary with conformational diversity based on its potency and selectivity in functional adhesion cellular assays. Visabron c (4–4)’s serum stability, pharmacokinetics, and therapeutic effects following ip injection were assessed in an experimental autoimmune encephalomyelitis (EAE) animal model. Furthermore, visabron c (4–4)’s lack of toxic effects in mice was verified by blood analysis, tissue pathology, immunogenicity, and “off-target” effects, indicating its significant tolerability and lack of immunogenicity. Visabron c (4–4) can be delivered systemically. The in vitro and in vivo data justify visabron c (4–4) as a safe alternative peptidomimetic lead compound/drug to monoclonal anti-α4 integrin antibodies, steroids, and other immunosuppressant drugs. Moreover, visabron c (4–4) design may pave the way for developing new therapies for a variety of other inflammatory and/or autoimmune diseases.

Apomorphine (APO), a potent treatment for Parkinson's disease, is only administered parenterally either as intermittent injections or as an infusion. This is due to extensive hepatic “first pass” metabolism. Prolonged delivery through buccal mucosa may be potential substitute for parenteral infusions. To investigate this concept of buccal mucosal delivery, permeability ex vivo studies were performed through excised porcine buccal mucosa by utilizing Ussing diffusion chamber. Permeability rates were assessed for APO from simulated saliva medium at pH 7.4 as well as with utilization of different permeability modifying methods. Lowering the pH to 5.9 decreased permeability rate six-fold, while addition of ethanol : propylene glycol solution elevated it four-fold. Addition of nano-scale lipospheres to the donor compartment delayed the accumulation of APO at the receiver side, prolongating the lag-time from one to approx. three hours. These findings were strengthened by results obtained with co-administration of permeability markers (standards) atenolol and metoprolol. Simulation of the obtained permeability rates to in vivo setup in human showed therapeutically relevant plasma levels when using the outcomes of the current study. These findings verify the novel concept of APO prolonged release buccal administration as a noninvasive substitute for parenteral infusions in treating Parkinson's disease.

Lipid-based drug delivery systems have been vastly investigated as a pharmaceutical method to enhance oral absorption of lipophilic drugs. However, these vehicles not only affect drug bioavailability but may also have an impact on gastric emptying, drug disposition, lymphatic absorption and be affected by lipid digestion mechanisms. The work presented here compared the pharmacokinetic (PK) behavior of the non-intoxicating cannabinoid cannabidiol (CBD) in sesame oil

Myeloid differentiation primary response 88 (MyD88) is an intracellular adaptor protein central to the signaling of multiple receptors involved in inflammation. Since innate immune inflammation promotes autoimmunity, MyD88 is an attractive target in autoimmune disease. We previously developed c(MyD 4-4), a novel cyclic peptide competitive inhibitor of MyD88 dimerization that is metabolically stable. Parenteral administration of c(MyD 4-4) reduces disease severity in a mouse model of the human autoimmune disease multiple sclerosis. We now show that N-terminal myristoylation of c(MyD 4-4) enhances the competitive inhibition of MyD88 dimerization in living cells, leading to improved inhibition of the Toll-like receptor and IL-1 receptor signaling. Importantly, myristoylation converts c(MyD 4-4) to an orally bioavailable inhibitor of MyD88. Oral administration of c(MyD 4-4) significantly lowered the inflammatory cytokines secreted by peripheral autoimmune T cells in mice immunized with myelin antigens and ameliorated disease severity in the mouse model of multiple sclerosis. Taken together, we show the conversion of a protein active region to a metabolically stable, selective cyclic peptide that is orally bioavailable.

Contrary to human, porcine mucosa of the inner side of the lip is parakeratinized. Thus, although desirable due to its large surface area, it does not closely resemble human buccal mucosa to be considered a suitable model for systemic drug delivery research. Nevertheless, it can be utilized for comparative screening of topical or systemic delivery of bioactive agents, mostly lipophilic such as cannabinoids.

Delivery of drugs through oral mucosa enables bypass of the gastrointestinal tract and “first pass“ metabolism in the liver and the gut. Thus, a higher and less variable bioavailability can be obtained. Mechanisms of this administration route for cannabidiol were investigated in the current research in pigs. Results show that cannabidiol has substantially low permeability rate over 8 h through oral mucosa and accumulates significantly within it. Furthermore, following the removal of the delivery device, residual prolongation of release from the oral mucosa into systemic blood circulation continues for several hours. This method of delivery enabled acquisition of clinically relevant plasma levels of cannabidiol. The absorption profile indicates that cannabidiol, as well as other lipophilic molecules, should be delivered through oral mucosa for systemic absorption from a device that conceals the drug and prevents its washout by the saliva flow and subsequent ingestion into gastrointestinal tract.

Insulin-dependent type-1 diabetes (T1D) is driven by autoimmune β-cell failure, whereas systemic resistance to insulin is considered the hallmark of insulin-independent type-2 diabetes (T2D). In contrast to this canonical dichotomy, insulin resistance appears to precede the overt diabetic stage of T1D and predict its progression, implying that insulin sensitizers may change the course of T1D. However, previous attempts to ameliorate T1D in animal models or patients by insulin sensitizers have largely failed. Sensitization to insulin by MEthyl-substituted long-chain DICArboxylic acid (MEDICA) analogs in T2D animal models surpasses that of current insulin sensitizers, thus prompting our interest in probing MEDICA in the T1D context. MEDICA efficacy in modulating the course of T1D was verified in streptozotocin (STZ) diabetic rats and autoimmune nonobese diabetic (NOD) mice. MEDICA treatment normalizes overt diabetes in STZ diabetic rats when added on to subtherapeutic insulin, and prevents/delays autoimmune T1D in NOD mice. MEDICA treatment does not improve β-cell insulin content or insulitis score, but its efficacy is accounted for by pronounced total body sensitization to insulin. In conclusion, potent insulin sensitizers may counteract genetic predisposition to autoimmune T1D and amplify subtherapeutic insulin into an effective therapeutic measure for the treatment of overt T1D.

The lipophilic phytocannabinoids cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) show therapeutic efficacy in various medical conditions. Both molecules are poorly water soluble and subjected to extensive first pass metabolism in the gastrointestinal tract, leading to a limited oral bioavailability of approximately 9%. We have developed an advanced lipid based Self-Emulsifying Drug Delivery System termed Advanced Pro-NanoLiposphere (PNL) pre-concentrate. The PNL is composed of lipid and emulsifying excipients of GRAS status and are known to increase solubility and reduce Phase I metabolism of lipophilic active compounds. Advanced PNLs are PNLs with an incorporated natural absorption enhancers. These molecules are natural alkaloids and phenolic compounds which were reported to inhibit certain phase I and phase II metabolism processes. Here we use piperine, curcumin and resveratrol to formulate the Advanced-PNL formulations. Consequently, we have explored the utility of these Advanced-PNLs on CBD and THC oral bioavailability. Oral administration of CBD-piperine-PNL resulted in 6-fold increase in AUC compared to CBD solution, proving to be the most effective of the screened formulations. The same trend was found in pharmacokinetic experiments of THC-piperine-PNL which resulted in a 9.3-fold increase in AUC as compared to THC solution. Our Piperine-PNL can be used as a platform for synchronized delivery of piperine and CBD or THC to the enterocyte site. This co-localization provides an increase in CBD and THC bioavailability by its effect at the pre-enterocyte and the enterocyte levels of the absorption process. The extra augmentation in the absorption of CBD and THC by incorporating piperine into PNL is attributed to the inhibition of Phase I and phase II metabolism by piperine in addition to the Phase I metabolism and P-gp inhibition by PNL. These novel results pave the way to utilize piperine-PNL delivery system for other poorly soluble, highly metabolized compounds that currently cannot be administered orally.

Nowadays, therapeutic indications for cannabinoids, specifically Δ9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) are widening. However, the oral consumption of the molecules is very limited due to their highly lipophilic nature that leads to poor solubility at the aqueous environment. Additionally, THC and CBD are prone to extensive first pass mechanisms. These absorption obstacles render the molecules with low and variable oral bioavailability. To overcome these limitations we designed and developed the advanced pro-nanolipospheres (PNL) formulation. The PNL delivery system is comprised of a medium chain triglyceride, surfactants, a co-solvent and the unique addition of a natural absorption enhancer: piperine. Piperine was selected due to its distinctive inhibitory properties affecting both Phase I and Phase II metabolism. This constellation self emulsifies into nano particles that entrap the cannabinoids and the piperine in their core and thus improve their solubility while piperine and the other PNL excipients inhibit their intestinal metabolism. Another clear advantage of the formulation is that its composition of materials is approved for human consumption. The safe nature of the excipients enabled their direct evaluation in humans. In order to evaluate the pharmacokinetic profile of the THC-CBD-piperine-PNL formulation, a two-way crossover, single administration clinical study was conducted. The trial comprised of 9 healthy volunteers under fasted conditions. Each subject received a THC-CBD (10.8mg, 10mg respectively) piperine (20mg)-PNL filled capsule and an equivalent dose of the oromucosal spray Sativex® with a washout period in between treatments. Single oral administration of the piperine-PNL formulation resulted in a 3-fold increase in Cmax and a 1.5-fold increase in AUC for THC when compared to Sativex®. For CBD, a 4-fold increase in Cmax and a 2.2-fold increase in AUC was observed. These findings demonstrate the potential this formulation has in serving as a standardized oral cannabinoid formulation. Moreover, the concept of improving oral bioavailability described here, can pave the way for other potential lipophilic active compounds requiring enhancement of their oral bioavailability.

Piperine is an alkaloid naturally found in black pepper with a myriad of pharmacological attributes. Piperine's most far reaching indication is drug absorption enhancment, with supportive data regarding its ability to inhibit first pass effect mechanisms. However, alongside these findings, the role of piperine as an absorption enhancer is undermined with publications stating an apparent effect of a metabolic inducer. The aim of this work is to investigate the effect of repeated administration of piperine in a lipid-based formulation ,on oral absorption of cannabidiol (CBD), compared to acute piperine dosing. The effect of piperine on CBD absorption was determined pre-clinically in the freely moving rat model. Results of this work demonstrated that there was no significant difference in piperine's effect, when given chronically or in a single dose regimen. Both groups resulted in approximate 2.5-fold increase in oral bioavailability of CBD compared to control group without piperine.

Introduction: Sativex® spray is clinically utilized to deliver delta9-tetrahydrocannabinol and cannabidiol to oral mucosa for systemic absorption. We challenge the consensus that the mechanism of absorption following the oro-mucosal application occurs via the buccal tissue. Areas covered: Correctness of the consensus of this absorption pathway arose when reviewing publications regarding the influence fed versus fasting states have on pharmacokinetics of these cannabinoids administered to the oral mucosa. This finding is more suitable for peroral administration, where stomach content affects the absorption profile. We hypothesize that these cannabinoids are ingested and absorbed in the gastrointestinal tract. Expert opinion: Although clinical importance of Sativex® is not disputed, the wide acceptance of its being a successful example of drug delivery through oral mucosa is questionable. Sativex® acts as an example for other drugs delivered to oral mucosa for systemic absorption and unintentionally washed by the saliva flow into the gastrointestinal tract. Delivery of each medicine through oral mucosa should be validated in-vivo to ensure this route to be the predominant one. Revealing the underlying absorption mechanisms would enable predicting the impact of different physiological parameters such as saliva flow and fed/fasting states on the pharmacokinetics of the delivered medication.

Humanin (HN) is a 24-amino acid mitochondrial-derived peptide, best known for its ability to protect neurons from damage caused by ischemic stroke and neurodegenerative insults and cardiomyocytes from myocardial infarction or doxorubicin (Dox)-induced cardiotoxicity. This study examines the neuroprotective and myoprotective effects of HN novel synthetic analogs HUJInin and c(D-Ser14-HN), prepared by solid-phase peptide synthesis. The cellular models employed were oxygen-glucose-deprivation (OGD) followed by reoxygenation (R)-induced neurotoxicity in PC12 and SH-SY5Y neuronal cell cultures and Dox-induced cardiotoxicity in H9c2 and C2C12 myoblast cell cultures, respectively. Necrotic and apoptotic cell death was measured by LDH release and caspase-3 activity. Erk 1/2 and AKT phosphorylations were examined by western blotting. Mitochondrial calcium and mitochondrial membrane potential were measured using the fluorescent dye tetramethylrhodamine-methyl ester. It was found that HUJInin and c(D-Ser14-HN) conferred significant dose-dependent neuroprotection, a phenomenon related to attenuation of OGD insult-induced Erk 1/2 phosphorylation, stimulation of AKT phosphorylation and improvement of mitochondrial functions. These peptides also conferred myoprotective effect towards Dox-induced apo-necrotic cell death insults. HUJInin and c(D-Ser14-HN) synthetic analogs may provide new lead compounds for the development of a potential candidate drug for stroke treatment and/or Dox-induced cardiotoxicity therapy in cancer patients.

The aim of this research was to investigate the effect of the lipid component in self-emulsifying drug delivery systems on the oral absorption of major cannabinoids Δ9-tetrahydrocannabinol (THC) and Cannabidiol (CBD). The investigated lipids were either long chain triglycerides (LCT) or medium chain triglycerides (MCT) with different composition, fatty acid chain length, degree of saturation and their absorption pathway to the systemic circulation. Formulations were developed with the purpose of creating thermodynamically stable oil-in-water nano emulsions/suspensions with particle size of 50 nm or less which carry the lipophilic drug and increase water solubility. Following a methodic screening of suitable excipients in-vitro, leading formulations based on sesame oil or MIGLYOL® 812N (Type I LCT/MCT SNEDDS) and cocoa butter or tricaprin (Type II LCT/MCT SNEDDS) were investigated in the freely moving rat model. Results in rat model demonstrated that the effect of each type of lipid on bioavailability of cannabinoids is not straightforwardly anticipated. The differences in the effect of LCT and MCT on absorption was not substantial for Type I formulations, however, more prominent for Type II formulations. This unpredictable behavior in-vivo demonstrates the importance of investigating each vehicle pre-clinically, following the in-vitro development.

Hydrophilic peptides constitute most of the active peptides. They mostly permeate via tight junctions (paracellular pathway) in the intestine. This permeability mechanism restricts the magnitude of their oral absorption and bioavailability. We hypothesized that concealing the hydrophilic residues of the peptide using the lipophilic prodrug charge masking approach (LPCM) can improve the bioavailability of hydrophilic peptides. To test this hypothesis, a cyclic N-methylated hexapeptide containing Arg-Gly-Asp (RGD) and its prodrug derivatives, masking the Arg and Asp charged side chains, were synthesized. The library was evaluated for intestinal permeability in vitro using the Caco-2 model. Further investigation of metabolic stability ex vivo models in rat plasma, brush border membrane vesicles (BBMVs), and isolated CYP3A4 microsomes and pharmacokinetic studies was performed on a selected peptide and its prodrug (peptide 12). The parent drug analogues were found to have a low permeability rate in vitro, corresponding to atenolol, a marker for paracellular permeability. Moreover, palmitoyl carnitine increased the P

MyD88 is a cytoplasmic adaptor protein that plays a central role in signaling downstream of the TLRs and the IL1R superfamily. We previously demonstrated that MyD88 plays a critical role in EAE, the murine model of multiple sclerosis, and showed that the MyD88 BB-loop decoy peptide RDVLPGT ameliorates EAE. We now designed and screened a library of backbone cyclized peptides based on the linear BB loop peptide, to identify a metabolically stable inhibitor of MyD88 that retains the binding properties of the linear peptide. We identified a novel cyclic peptide protein mimetic that inhibits inflammatory responses to TLR ligands, and NFκB activation in response to IL-1 activation. The inhibitor, c(MyD 4-4), is metabolically stable in comparison to the linear peptide, blocks MyD88 in a specific manner, and inhibits MyD88 function by preventing MyD88 dimerization. Finally, treatment of mice with c(MyD 4-4) reduced the severity of clinical disease in the murine EAE model of multiple sclerosis. Thus, modulation of MyD88-dependent signaling using c(MyD 4-4) is a potential therapeutic strategy to lower innate immune inflammation in autoimmune CNS disease.

Phase II biotransformation reactions have been gaining more attention due to their acknowledged significance in drug bioavailability, drug development, and drug-drug interactions. However, the predominant role of phase I metabolism has always overshadowed phase II metabolism, resulting in insufficient data regarding its mechanisms. In this paper, we investigate the effect of an advanced lipid based formulation on the phase II metabolism process of glucuronidation, occuring in the enterocytes monolayer. The investigated formulation is a self-emulsifying drug delivery system, termed pro-nano lipospheres, which contains the natural absorption enhancer piperine. To evaluate the effect of this formulation on direct glucuronidation we chose the model molecule raloxifene. First, glucuronidation is the main clearance pathway of this compound without involvement of preceding mechanisms. Second, raloxifene's extensive glucuronidation site is primarily at the intestine. Raloxifene's oral bioavailability was determined in a series of pharmacokinetic experiments using the freely moving rat model. In order to test the effect of the formulation on the relevant UGT enzymes reported in the clinic, we used the in vitro method of UGT-Glo Assay. Coadministration of raloxifene and piperine pro-nano lipospheres to rats resulted in a 2-fold increase in the relative oral bioavailability of raloxifene. However, coadministration of raloxifene with blank pro-nano lipospheres had no effect on its oral bioavailability. In contrast to the difference found in vivo between the two vehicles, both formulations extended an inhibitory effect on UGT enzymes in vitro. Ultimately, these findings prove the ability of the formulation to diminish intestinal direct phase II metabolism which serves as an absorption obstacle for many of today's marketed drugs. Pro-nano lipospheres is a formulation that serves as a platform for the simultaneous delivery of the absorption enhancer and a required drug. The discrepancy found between the in vivo and in vitro models demonstrates that the in vitro method may not be sensitive enough to distinguish the difference between the formulations.

JS403 is a carbamoylphosphonate (CPO) molecule that showed anti-metastatic properties in mice. Since JS403 is intended to be a chronic prophylactic drug, the preferred route of administration should be oral. However, it exhibits poor oral bioavailability of less than 1%. The poor intestinal permeability and high solubility implies its classification as BCS class III drug. The aim of this study was to overcome the limited intestinal permeation of JS403 that is regarded as an unmet need in the pharmaceutical industry for this class of drugs. Therefore, the impact of acceptable absorption enhancers on the intestinal permeability of JS403 were examined using established experimental models. The absorption enhancers were: I) sodium caprate (C10), II) sodium deoxycholate (SDC) and III) mono-carboxymethylated chitosan (MCC). The effect of each enhancer was examined alone and also in combinations. In-vitro permeability through enterocytes monolayer was studied using the Caco-2 model, while the oral bioavailability was determined by using the freely moving rat model. The results of this investigation showed that while the use of a single absorption enhancer had no effect on JS403 permeability, the combination of C10 and sodium deoxycholate increased the permeability of JS403 by 10-fold in the in-vitro model. In addition, this blend showed a 2-fold elevation in JS403 oral bioavailability. Both in-vitro and in-vivo results highlight the synergistic potential of the combined enhancers C10 and sodium deoxycholate in enhancing oral bioavailability of BCS class III medications.

Recent structural studies on libraries of cyclic hexapeptides led to the identification of common backbone conformations that may be instrumental to the oral availability of peptides. Furthermore, the observation of differential Caco-2 permeabilities of enantiomeric pairs of some of these peptides strongly supports the concept of conformational specificity driven uptake and also suggests a pivotal role of carrier-mediated pathways for peptide transport, especially for scaffolds of polar nature. This work presents investigations on the Caco-2 and PAMPA permeability profiles of 13 selected N-methylated cyclic pentaalanine peptides derived from the basic cyclo(-D-Ala-Ala4 -) template. These molecules generally showed moderate to low transport in intestinal epithelia with a few of them exhibiting a Caco-2 permeability equal to or slightly higher than that of mannitol, a marker for paracellular permeability. We identified that the majority of the permeable cyclic penta- and hexapeptides possess an N-methylated cis-peptide bond, a structural feature that is also present in the orally available peptides cyclosporine A and the tri-N-methylated analogue of the Veber-Hirschmann peptide. Based on these observations it appears that the presence of N-methylated cis-peptide bonds at certain locations may promote the intestinal permeability of peptides through a suitable conformational preorganization.

There is a growing clinical interest in developing and commercializing pharmaceutical-grade cannabinoid products, containing primarily tetrahydrocannabinol (THC) and cannabidiol (CBD). The oral bioavailability of THC and CBD is very low due to extensive "first-pass" metabolism. A novel oral THC and CBD formulation, PTL401, utilizing an advanced self-emulsifying oral drug delivery system, was designed to circumvent the "first-pass" effect. In this study, the bioavailability of THC and CBD from the PTL401 capsule was compared with similar doses from a marketed reference oromucosal spray (Sativex ® ). Fourteen healthy male volunteers received, on separate treatment days, either a single dose of PTL401 or an equivalent dose of the oromucosal spray. Blood samples for pharmacokinetic analyses were collected, and safety and tolerability were assessed. PTL401 yielded 1.6-fold higher plasma C max than the equivalent dose of the oromucosal spray, for both THC and CBD. Their relative bioavailability was also higher (131% and 116% for CBD and THC, respectively). Values of T max were significantly shorter for both CBD and THC (median of 1.3 h for PTL401 vs. 3.5 h for the spray). The pharmacokinetic profiles of the active 11-OH-THC metabolite followed the same pattern as THC for both routes of delivery. No outstanding safety concerns were noted following either administration. We conclude that PTL401 is a safe and effective delivery platform for both CBD and THC. The relatively faster absorption and improved bioavailability, compared to the oromucosal spray, justifies further, larger scale clinical studies with this formulation.

Amphotericin B (AMB) arabinogalactan (AG) conjugate was synthesized by the conjugation of AMB to oxidized AG by reductive amination. The conjugate was evaluated for in vitro antifungal activity and in vivo toxicity. Optimization of the conjugation process was investigated using large batches of 100 g, which are 20 times larger than previously reported for AMB-AG conjugation. The efficacy of AMB-AG conjugates was studied as a function of reaction conditions and time, aldehyde/reducing agent mole ratio, and purification procedure. The most potent AMB-AG conjugate having low minimal inhibitory concentration (MIC) and high maximal tolerated dose (MTD) was obtained following reduction with NaBH4 at 1:2 mol ratio (AG units/NaBH4) at 25 °C for 24 h. AMB-AG conjugate prepared under these conditions demonstrated MIC of 0.5 mg/L (equiv of AMB) in Candida albicans, and an MTD of 60 mg/kg (equiv of AMB) in mice, while AMB clinical formulation (Fungizone) demonstrated high toxicity (MTD = 3 mg/kg). These findings confirm the simplicity and reproducibility of the conjugation allowing this method to be applied on larger scale production.

Bipolar-disorder (manic-depressive illness) is a severe chronic illness affecting ∼1% of the adult population. It is treated with mood-stabilizers, the prototypic one being lithium-salts (lithium), but it has life threatening side-effects and a significant number of patients fail to respond. The lithium-inhibitable enzyme inositol-monophosphatase (IMPase) is one of the viable targets for lithium's mechanism of action. Calbindin-D28k (calbindin) up-regulates IMPase activity. The IMPase-calbindincomplex was modeled using the program MolFit. The in-silico model indicated that the 55-66 amino-acid segment of IMPase anchors calbindin via Lys59 and Lys61 with a glutamate in between (Lys-Glu-Lys motif) and that the motif interacts with residues Asp24 and Asp26 of calbindin. We found that differently from wildtype calbindin, IMPase was not activated by mutated calbindin in which Asp24 and Asp26 were replaced by alanine. Calbindin's effect was significantly reduced by a linear peptide with the sequence of amino acids 58-63 of IMPase (peptide 1) and by six amino-acid linear peptides including at least part of the Lys-Glu-Lys motif. The three amino-acid peptide Lys-Glu-Lys or five amino-acid linear peptides containing this motif were ineffective. Mice administered peptide 1 intracerebroventricularly exhibited a significant anti-depressant-like reduced immobility in the forced-swim test. Based on the sequence of peptide 1, and to potentially increase the peptide's stability, cyclic and linear pre-cyclic analog peptides were synthesized. One cyclic peptide and one linear pre-cyclic analog peptide inhibited calbindin-activated brain IMPase activity in-vitro. Our findings may lead to the development of molecules capable of inhibiting IMPase activity at an alternative site than that of lithium.

During recent years there has been increasing interest in the Lycopodium alkaloid huperzine A as a potential therapeutic agent for neurodegenerative diseases. This study aimed to characterize huperzine A's permeability across the enterocyte barrier along the gastrointestinal tract with an emphasis on the effect of ionization on the drug absorption. Intestinal permeability of huperzine A was evaluated by in vitro Caco-2 and parallel artificial membrane permeation assay models and by the ex vivo Ussing chamber model. The permeability rate was strongly dependent on the degree of ionization and increased with elevation of the donor medium pH in all studied models. The transport of the unionized fraction was similar to the permeability of the markers for passive transcellular diffusion. Addition of the paracellular permeability modulator palmitoylcarnitine in the Caco-2 model led to significant enhancement in the permeability of the ionized huperzine A fraction. No evidence of active transport of huperzine A was detected in this study. The Ussing chamber model experiments showed similar drug permeability along the entire rat intestine. In conclusion, huperzine A permeates the intestinal border mainly by passive transcellular diffusion whereas some fraction, dependent on the degree of huperzine A ionization, is absorbed by the paracellular route. Huperzine A's permeability characteristics pave the way to the development of its oral extended release dosage form. The specific population of the potential users of huperzine A and the high potency of this molecule support the rationale for such a delivery.

Carbamoylphosphonates (CPOs) have been identified as inhibitors of matrix metalloproteinases (MMPs) and as orally active, bioavailable, and safe antimetastatic agents. In this article, we focus on the direct antitumor activity of the CPOs. We discovered that CPOs also inhibit carbonic anhydrases (CAs), especially the IX and XII isoforms identified as cancer promoting factors. Thus, CPOs can be regarded as novel nontoxic drug candidates for tumor microenvironment targeted chemotherapy acting by two synergistic mechanisms, namely, inhibiting CAs and MMPs simultaneously. We have also demonstrated that the ionized CPO acid is unable to cross the cell membrane and thus limited to interact with the extracellular domains of isozymes CAIX and CAXII. Finally, applying CPOs against cancer cells in hypoxic conditions resulted in the dose dependent release of lactate dehydrogenase, confirming the direct interaction of the CPOs with the cancer related isozymes CAIX and XII and thereby promoting cellular damage.

Background Amphotericin-B (AMB) is associated with toxicity such as renal impairment, hypokalemia and infusion-related events (IRE). With the advent of AMB lipid formulations and newer antifungal drugs, presenting improved safety profiles, it was suggested that using the conventional deoxycholate (AMB-D) formulation should no longer be regarded acceptable. Objectives Evaluation of real-life incidence of AMB-D-related adverse-drug effects (ADE) and associated costs. Setting Hadassah Hebrew University Medical Center, Jerusalem, Israel, a tertiary 1,100-bed teaching hospital. Methods A 1-year single-center prospective observational study following all patients administered AMB-D. Various parameters related to AMB-D administration were recorded. Main outcome measures Subsequent ADE-related events, discontinuations, switch to alternative antifungals and related resource-utilization were monitored. Results Among 119 patients (60 children, 59 adults) receiving AMB-D, serum creatinine doubling from baseline, hypokalemia and IRE occurred in 14.3 % (15 % in children, 13.6 % in adults), 16.8 % (16.6 % in children, 16.9 % in adults) and 10.9 % (10 % in children, 11.8 % in adults), respectively. AMB-D was discontinued due to an ADE in 12.6 % of patients (6.7 % in children, 18.6 % in adults). The total annual cost associated with AMB-D use was €58,600. Conclusion The clinical as well as economic burden of AMB-D associated ADE, as observed in real-life settings, appears to be manageable. Considering the significant cost implications associated, as suggested by simulated evaluation of an overall theoretic replacement of AMB-D by an equivalent volume of alternative antifungals, total abandonment of AMB-D appears unjustified.

Emergence of antimicrobial resistance is among the most worrisome issues in public health worldwide. Vancomycin resistance is rapidly spreading, resulting in increased morbidity, mortality, and healthcare-associated costs. Multiple strategies are required to preserve the effectiveness of this essential antibiotic. It has been recently shown that biliary excretion of vancomycin following parenteral administration results in significant fecal concentrations of vancomycin that may lead to selection of vancomycin-resistant strains within the colon. In this study we present a novel strategy for preventing this undesired effect and its consequences, using chemical trapping of vancomycin by a tripeptide analog that mimics the natural bacterial vancomycin binding-site. Initially, we demonstrated that a tripeptide analog can neutralize vancomycin activity against Enterococci at a molar excess of 28. In the second phase, two chemical modifications, designed to attach the tripeptide to vancomycin covalently, were explored. Attachment of a 4-flurosulfonyl-benzoic acid (FSBA) moiety to the parent tripeptide resulted in vancomycin neutralization at a molar ratio of less than 4:1. Finally it was shown that the FSBA-bound tripeptide analog can prevent in-vitro selection of vancomycin-resistant Enterococci (VRE) from a mixed vancomycin susceptible/resistant population following exposure to vancomycin. These findings demonstrate the ability of the proposed strategy to prevent selection of VRE. The present proof-of-concept study provides the basis for further development of the proposed strategy. Further, this strategy may be implemented for combating resistance to other antimicrobials.

We have recently generated lipophilic D-xylose derivatives that increase the rate of glucose uptake in cultured skeletal muscle cells in an AMP-activated protein kinase (AMPK)-dependent manner. The derivative 2,4:3,5-dibenzylidene-D-xylose-diethyl dithioacetal (EH-36) stimulated the rate of glucose transport by increasing the abundance of glucose transporter-4 in the plasma membrane of cultured myotubes. The present study aimed at investigating potential antihyperglycaemic effects of EH-36 in animal models of diabetes. Two animal models were treated subcutaneously with EH-36: streptozotocin-induced diabetes in C57BL/6 mice (a model of insulin-deficient type 1 diabetes), and spontaneously diabetic KKAy mice (Kuo Kondo rats carrying the A(y) yellow obese gene; insulin-resistant type 2 diabetes). The in vivo biodistribution of glucose in control and treated mice was followed with the glucose analogue 2-deoxy-2-[(18) F]-D-glucose; the rate of glucose uptake in excised soleus muscles was measured with [(3) H]-2-deoxy-D-glucose. Pharmacokinetic parameters were determined by non-compartmental analysis of the in vivo data. The effective blood EH-36 concentration in treated animals was 2 μM. It reduced significantly the blood glucose levels in both types of diabetic mice and also corrected the typical compensatory hyperinsulinaemia of KKAy mice. EH-36 markedly increased glucose transport in vivo into skeletal muscle and heart, but not to adipose tissue. This stimulatory effect was mediated by Thr(172) -phosphorylation in AMPK. Biochemical tests in treated animals and acute toxicological examinations showed that EH-36 was well tolerated and not toxic to the mice. These findings indicate that EH-36 is a promising prototype molecule for the development of novel antidiabetic drugs.

Rheumatoid arthritis (RA) is a common human leukocyte antigen-associated disease. Most RA patients have a five-residue sequence motif called the shared epitope (SE) in the DRβ-chain of the HLA-DRB1 protein. The SE was found to activate nitric oxide (NO) production, suggesting a possible mechanism for RA development. The native conformation of the SE is presumed to be an α-helix, thus using cyclic peptides to stabilize this conformation may produce a potent SE mimetic which will have drug- like properties. We present the development of a backbone cyclic SE mimetic that activates NO production in the low nM range. Circular dichroism analysis revealed a conformational change from unstructured for the parent linear peptides to β– turn in the cyclic analogs. The most active cyclic analog is completely stable towards trypsin/chymotrypsin degradation while the linear 15-mer analogs completely degraded within 30 minutes. The outcome of this study is a potent cyclic peptide with drug-like properties that can be used as a template for drug development.

Recent progress in peptide synthesis simplified the synthesis of multiple N-methylation of peptides. To evaluate how multiple N-methylation affects the bioavailability of peptides, a poly alanine cyclic hexapeptide library (n = 54), varying in the number of N-methyl (N-Me) groups (1-5 groups) and their position, was synthesized. The peptides were evaluated for their intestinal permeability in vitro using the Caco-2 model. Further evaluation of the transport route of chosen analogues was performed using rat excised viable intestinal tissue, a novel colorimetric liposomal model and the parallel artificial membrane permeability assay (PAMPA). While most members were found to have poor permeability (permeability coefficient, P(app)1 x 10⁻⁶ cm/s, lower than mannitol, the marker for paracellular permeability), 10 analogues were found to have high Caco-2 permeability, (P(app)1 x 10⁻⁵ cm/s, similar to testosterone, a marker of transcellular permeability). No correlation was found between the number of N-methylated groups and the enhanced permeability. However, 9/10 permeable peptides in the Caco-2 model included an N-Me placed adjacently to the D-Ala position. While the exact transport route was not fully characterized, the data suggests a facilitated diffusion. It can be concluded that multiple N-methylation of peptides may improve intestinal permeability, and therefore can be utilized in the design of orally available peptide-based therapeutics.

Beta-lactam antimicrobials, commonly used in both veterinary and human medicine, generally present short biologic half-lives, whereas their activity is enhanced as pathogen exposure is prolonged. These properties necessitate multiple-dose regimens of standard dosage forms, thereby hampering pet owner adherence, frequently resulting in therapeutic failure. This study presents a novel controlled-release gastroretentive oral drug delivery system for beta-lactams with which single-dose administration provides an effective antimicrobial course, optimizing pharmacokinetic (PK)-pharmacodynamic (PD) profiles, minimizing adverse effects and emergence of antimicrobial resistance and facilitating adherence. Our prototype sustained-delivery swelling-tablet (SDST), based on a degradable hydrophilic polymeric matrix, was designed to enable continuous input of these drugs to their absorption sites over several days. Several SDST formulations of the beta-lactam amoxicillin were evaluated in in vitro dissolution studies. Two formulations were selected for further in vivo canine studies, for determination of gastric retention and PK-PD profiling. Prolonged gastric retention times maintaining allowed for maintained effective drug concentrations against many clinically relevant pathogens for more than 48 h for one formulation and more than 5 days for the other. Both SDST formulations offer significant advantages over standard immediate-release therapy in achieving PK-PD goals and enhancing adherence. The prototypical formulations represent a novel platform which may be modified to meet various clinical requirements.

Dosage forms of antimicrobials play a critical role in facilitating the attainment of pharmacokinetic-pharmacodynamic (PK-PD) targets as well as adherence in both veterinary and human medicine. The purpose of this study was to develop and evaluate a controlled-release subcutaneous amoxicillin implant for single-dose therapy of large ruminants such as goats, sheep, and deer. The degradable implant, designed to attain PK-PD targets following single administration, was evaluated for amoxicillin release rate and time-concentration profile. In vitro release studies demonstrated constant-rate release of approximately 40% of amoxicillin content within 96 h. In an in vivo study in goats, serving as a model for target animals, a serum concentration of approximately 0.4 mg/L was achieved within 8 h of implant insertion and maintained for >6 days. In comparison, in control goats given a standard single intramuscular amoxicillin dose of 15 mg/kg, amoxicillin peaked at 1.2 mg/L after 1 h, rapidly dropping to below detection level at 8 h. These results suggest that the proposed implant offers a unique modality for animal caregivers to conveniently administer a full antimicrobial course following a single dose of an efficient PK-PD-optimized dosage form. Furthermore, modifications of implant composition may allow for tailoring of its characteristics to various PK, PD, microbiological, and clinical requirements.

Peptides are promising candidates as therapeutic agents due to their wide involvement in physiological processes. However, their often non-selective activity and their poor drug-like properties, mainly their inherent low stability to enzymatic degradation and poor oral bioavailability, limit their clinical potential. Somatostatin is a peptide hormone involved in many different biological functions. The role of its five different receptor subtypes and their interplay in medicinal processes is only partially understood. In addition, it suffers from poor drug-like properties.We review several promising chemical modifications, including head-to-tail and backbone cyclization as well as N-methylation, which were applied throughout the years in the development of various somatostatin analogs.These modifications led to enhanced metabolic stability and intestinal permeability. In addition, several analogs exhibited specific receptor subtype activation.The results presented in this review suggest a potential use of these chemical modifications in order to achieve required characteristics for a bioactive peptide, mainly for clinical usage.

Several case reports indicate that carbapenem antibiotics, especially meropenem, may decrease the plasma concentrations of valproic acid (VPA), thus decreasing its therapeutic activity. To investigate the onset, severity, and dose dependency of the interaction between meropenem and VPA, the authors carried out a retrospective evaluation of data collected during 24 months from patients hospitalized in a tertiary medical center. The analysis included 36 patients. VPA mean +/- SEM plasma concentration decreased from of 50.8 +/- 4.5 microg/mL to 9.9 +/- 2.1 microg/mL (P < .001) following meropenem administration. After discontinuation of meropenem, VPA plasma concentrations remained low for 7 days and then gradually increased after 8 to 14 days, reaching values comparable to those before meropenem initiation. Different daily VPA doses showed a similar pattern of decreased VPA concentrations. The mean decrease in individual plasma VPA concentration was 82.1% +/- 2.7%. The mean VPA plasma concentration of patients in whom samples were drawn within 24 hours of meropenem initiation was 9.9 +/- 3.2 microg/mL. In conclusion, the interaction between meropenem and VPA causes a significant decrease in VPA plasma concentration, apparently within 24 hours. As the therapeutic effects of VPA are plasma concentration dependent, the data suggest that these drugs should not be administered concomitantly.

Guaifenesin is a very commonly used and prescribed oral expectorant drug. However, its mechanism of action is not completely elucidated and the available information is limited. The purpose was to evaluate whether guaifenesin action on respiratory tract secretion is mediated through a reflex stimulation of the gastric mucosa or by the systemic exposure due to the absorption of the drug to the blood circulation.Guaifenesin was administered to rats by various routes: intravenous bolus, oral gavage, and gastric, jejunal or cecal infusions (through surgically implanted catheters). Phenol red respiratory tract secretion (after intraperitoneal or intravenous injection) was used as a marker for degree of expectorant action. Administration of saline by gavage was used as control.Respiratory secretion following oral bolus was approximately 2-fold higher (p0.05) than that of control. Following IV administration the increase of respiratory secretion did not occur despite the fact that systemic exposure to guaifenesin was 1.5-fold higher than following oral administration. The abdominal surgery was found to eliminate the effect of guaifenesin although it did not change systemic absorption. Guaifenesin was equally absorbed from all parts of the gastrointestinal tract.It was demonstrated that expectorant action of guaifenesin is mediated by stimulation of the gastrointestinal tract and not by the systemic exposure to the drug.

Gastro-retentive dosage form (GRDF) is a controlled-release modality of drug delivery technology that allows continuous administration to the upper part of the gastrointestinal tract. The manuscript summarizes various aspects that should be considered for the successful implementation of these region-specific delivery systems, including underlying physiological principles, technologies, and performance assessment approaches. In particular it focuses on characterization of potential drug candidates for GRDF and the anticipated pharmacokinetic and pharmacodynamic advantages associated with GRDF administration. These considerations are demonstrated using gabapentin as a representative narrow absorption window drug. The pharmacokinetic model that was developed for description of oral absorption of gabapentin in humans included variable intragastric input functions, saturable absorption kinetics and limited absorption window in the proximal gut. The pharmacokinetic profiles obtained via simulation demonstrated the potential benefits that can be accomplished by GRDF for gabapentin, including dose-proportional absorption, extended duration of absorption and thereby reduced dosing frequency and lowered total daily dose. Such pharmacokinetic modeling and simulation are shown to be an important and useful tool that can be used to optimize the selection of the mode of oral drug administration, including GRDF approach.

Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction. The complexity of the disease and its treatments make MG patients particularly susceptible to adverse effects of drugs. MG is not a painful condition; however, as pain management armamentarium includes drugs from diverse pharmacological groups and with potential for drug-drug interactions, managing pain in patients with MG can be challenging. The underlying disease and the concomitant medications of each patient must be considered and the analgesic treatment individualized. This review presents an update on the various aspects of pain pharmacotherapy in patients with MG, focusing primarily on medications used to treat chronic pain. Drugs discussed are opioids, nonsteroidal anti-inflammatory drugs, antidepressants, anticonvulsants, muscle relaxants, benzodiazepines, intravenous magnesium, and local anesthetics. Drug interactions with agents used for MG treatment (acethylcholinesterase inhibitors, corticosteroids, immunosuppressants) and plasmapheresis are discussed. The clinical usefulness and limitations of each of the drug classes and agents are described.

Type 2 diabetes mellitus has reached epidemic proportions; therefore, the search for novel antihyperglycemic drugs is intense. We have discovered that D-xylose increases the rate of glucose transport in a non-insulin-dependent manner in rat and human myotubes in vitro. Due to the unfavorable pharmacokinetic properties of D-xylose we aimed at synthesizing active derivatives with improved parameters. Quantitative structure-activity relationship analysis identified critical hydroxyl groups in D-xylose. These data were used to synthesize various hydrophobic derivatives of D-xylose of which compound 19 the was most potent compound in stimulating the rate of hexose transport by increasing the abundance of glucose transporter-4 in the plasma membrane of myotubes. This effect resulted from the activation of AMP-activated protein kinase without recruiting the insulin transduction mechanism. These results show that lipophilic D-xylose derivatives may serve as prototype molecules for the development of novel antihyperglycemic drugs for the treatment of diabetes.

Objective Metformin is a polar positively charged compound. The aim of the study was to characterize its permeability across the human placenta using the ex vivo placental perfusion model. Methods Selected cotyledons from term placentas were cannulated and dually perfused. Metformin (10 mg/L, 1000 mg/L) and a permeability reference, antipyrine (50 mg/L), were added to the maternal circulation. Samples from maternal and fetal compartments were analyzed for metformin and antipyrine by high performance liquid chromatography (HPLC). The permeation of metformin was also studied using the parallel artificial membrane permeation assay (PAMPA) that was designed to predict passive transcellular permeability of drugs. Results In this study, 15 complete placental perfusion experimental set-ups were performed. The mean percent transport increased as metformin concentrations were raised and it was 11 ± 1.32 and 16.92 ± 0.98 for 10 mg/L and 1000 mg/L, respectively. The transport rate of metformin across the placenta was asymmetric yet, an active efflux against the gradient concentration could not be observed. Using the PAMPA assay, we confirmed that metformin does not cross by passive diffusion. Conclusion The data suggest that metformin permeability across the placenta is mediated by a carrier that transport cationic compounds bi-directionally, with a higher transfer rate from the fetal to the maternal side. Copyright © 2008 John Wiley & Sons, Ltd.

Objective The aim of the study was to quantify and characterize metformin transfer across the human placenta using an ex vivo placental perfusion model. Study design Placentas were obtained from vaginal deliveries or caesarean sections and selected cotyledons were cannulated and dually perfused. Metformin (1 μg/ml) and a permeability reference marker, antipyrine (50 μg/ml), were added to the maternal circulation. Each perfusion experiment was conducted for 180 min while samples were taken from the maternal and fetal compartments. The integrity and viability of the placenta were determined by measuring the flow rates, fetal artery inflow pressure, and hCG production during the experiments. Results Six complete experimental set-ups were completed. The maternal–fetal transport rates for metformin and antipyrine were 10.61 ± 2.85% and 30.98 ± 5.62%, respectively. The clearance index, calculated as the ratio between the permeabilities of metformin and antipyrine, was 0.34 ± 0.05. Conclusion The results indicate that metformin is able to cross the mature human placenta; thus, fetal exposure must be considered when treating pregnant women with metformin.

The purpose of this study was to evaluate the impact of general anesthesia on the lymphatic transport of orally administered drugs. Vitamin D 3 (0.5 mg/kg), a model lipophilic molecule with significant lymphatic transport, was administered to anesthetized rats in close proximity to the lymphatic cannulation procedure. The lymphatic and non-lymphatic absorption of the vitamin in this experimental model was compared to lymph-duct cannulated freely moving conscious rats. The amounts of vitamin D 3 transported via the lymph in the anesthetized animals throughout the time frame of this experimental model (8 h) were 25% lower as compared to the conscious animals, but showed similar absorption kinetics. However, the duration of the anesthesia is limited and thus failed to produce the complete picture of the absorption process. The cumulative percent of the vitamin dose that was recovered in the lymph as well as the vitamin plasma AUC values were both 25% lower in the anesthetized animals as compared to the conscious animals. Hence, the anesthesia did not influence the proportion of the vitamin fraction absorbed via the different pathways. The lymph flow rate was significantly decreased by the anesthesia (threefold), however, higher lymph vitamin concentrations in these animals led to lower differences in the vitamin lymphatic transport (25%) between the models. In conclusion, the anesthetized rat model is suitable for approximating the lymphatic transport. However, the conscious rat model is still required in order to have a more precise and complete measurement of lymphatic transport.

To assess the effects of the unabsorbed fraction of an orally administered antimicrobial drug which enters the colon on the emergence of resistance among the natural microflora, a phenomenon largely overlooked so far despite its clinical importance, especially when sustained release formulations are used.Effects of an orally administered model beta-lactam antibiotic (amoxicillin) on emergence of resistant bacteria were assessed using a microbiological assay for qualitative and quantitative determination of resistant bacteria in fecal samples of rats following gastric administration of the drug to rats for 4 consecutive days. Time- and site-controlled administration of a beta-lactamase to the rat colon was assessed as a potential strategy for prevention the emergence of resistant bacteria following oral administration of incompletely absorbed antimicrobials.Emergence of resistant bacteria was demonstrated following oral administration of amoxicillin to rats, whereas de-activation of the beta-lactam prior to entering the colon, by infusion of a beta-lactamase into the lower ileum, was shown to prevent the emergence of resistant colonic bacteria.This study illustrates the need to consider the emergence of antimicrobial resistance as a goal equally important to microbiological and clinical cure, when designing oral sustained-release delivery systems of antimicrobial drugs.

Following a high-fat meal, triglyceride-rich lipoproteins (TRL) are assembled in the gut and absorbed via the lymph into the blood circulation, producing a temporal hyperlipidemia. The purpose of this study is to verify the hypothesis that this transient acute postprandial hyperlipidemia affects the pharmacokinetics of lipophilic drugs on both absorption and disposition levels by the same underlying mechanism, namely the association of active lipophilic compounds with TRL in the plasma (disposition) or within the enterocyte (lymphatic transport). This concept was assessed in rats using two model compounds, DDT with high affinity to chylomicrons and diazepam which does not bind to chylomicrons. Oral administration of peanut oil significantly increased the AUC of plasma DDT concentrations following its IV bolus administration in comparison to a water treated group. On the other hand, the AUC of diazepam following IV bolus administration was the same in oil and water treated rats. While DDT is known to have significant lymphatic bioavailability, diazepam has negligible intestinal lymphatic transport (0.014+/-0.004% of a given dose). In conclusion, lipophilic molecules that bind extensively to TRL will be prone to both intestinal lymphatic transport and to post-absorptive changes in disposition (decrease in clearance and volume of distribution) following a high-fat meal.

A high-fat meal induces transient hyperlipidemia characterized by elevated triglyceride-rich lipoproteins (TRL) which are composed mainly of chylomicrons. The purpose of this work was to investigate the effect of this transient hyperlipidemia on the pharmacodynamics of lipophilic drugs, using DDT as a model compound since it binds extensively to TRL and has a distinct neurotoxic effect. The postprandial hyperlipidemia in rats was induced by oral administration of peanut oil and was monitored by measurement of plasma triglyceride levels. The control group received water instead of oil. The rats received a continuous intravenous infusion of DDT (10 mg/h) until onset of a predefined pharmacodynamic endpoint (facial muscle tremor). Plasma and brain samples were then obtained and assayed for DDT. Rats with postprandial hyperlipidemia required higher dose of DDT to induce onset of facial muscle tremor. At the pharmacodynamic endpoint, oil treated rats had significantly higher concentrations of DDT in plasma and in the chylomicron fraction, but DDT brain concentrations were the same in both groups. In conclusion, a high-fat meal induces postprandial hyperlipidemia that may significantly alter the pharmacological profile of lipophilic compounds that bind to TRL. This is due to alteration of the distribution characteristics of the lipophilic compound through its association with postprandial lipoproteins. However, this pharmacokinetic phenomenon did not affect the concentration-effect relationship at the site of action in the brain.

Uncertainty in the decision-making process for reimbursement of health technologies could be reduced if additional information were available. Although methods to evaluate the monetary value of the uncertainty have been previously described, an economic evaluation of alternative methods to acquire additional information has not yet been thoroughly explored. Should resources be allocated to a retrospective study design or to a randomised controlled trial (RCT) when additional information is deemed justified? We propose an approach for cost-effectiveness analysis of designs of future studies that are required to evaluate health technologies for reimbursement. Biases inherent in study designs are the main factor that differentiates the ability of the studies to predict the technology's benefit. By quantifying this inherent-bias effect, the incremental effectiveness of future studies can be evaluated. Economic consequences of decisions regarding prioritization of the technologies, along with the expected costs incurred by the study's execution, account for the cost component of the equation. Deducting the result retrieved for the retrospective design from that of the RCT design gives the net information benefit.

Autotaxin is an extracellular, two zinc-centered enzyme that hydrolyzes lysophosphatidyl choline to lysophosphatidic acid, involved in various cancerous processes, e.g. migration, proliferation and tumor progression. We examined the autotaxin inhibitory properties of extended structure carbamoylphosphonates (CPOs) PhOC(6)H(4)SO(2)NH(CH(2))nNHCOPO(3)H(2), with increasing lengths of methylene chains, (CH(2))(n), n = 4-8. Carbamoylphosphonates having n = 6, 7, 8 inhibited autotaxin in vitro with IC(50) ≈ 1.5 µM. Using an imaging probe we demonstrated that compound n = 6 inhibits recombinant autotaxin activity in vitro and in vivo, following oral CPO administration. Additionally, daily oral administration of compound n = 7 inhibited over 90% of lung metastases in a murine melanoma metastasis model. Both the carbamoylphosphonates and the enzymes reside and interact in the extracellular space expecting minimal toxic side effects, and presenting a novel approach for inhibiting tumor proliferation and metastasis dissemination.

Nonsteroidal anti-inflammatory drugs, including indomethacin, have been found in both epidemiological and clinical studies to reduce the prevalence and severity of Alzheimer's disease. However, long-term use of indomethacin is limited by significant gastrointestinal and renal toxicities. An indomethacin prodrug that delivers low and continuous blood levels of the drug showed a superior safety profile and similar efficacy in comparison to an equivalent dose of free indomethacin because of limited systemic exposure and preferred brain uptake. The purpose of the present investigation was to evaluate whether sustained systemic input causes an increased brain influx in comparison to rapid input of the drug. Oral indomethacin, indomethacin prodrug, or intravenous indomethacin infusion was administered to rats. The infusion was designed to mimic the plasma indomethacin levels resulting from the prodrug. The resultant blood levels and brain indomethacin uptake were evaluated. The brain indomethacin concentrations 8 h following indomethacin administration were 0.45, 0.3, and 0.31 microg/g after the oral indomethacin, oral prodrug, and intravenous infusion, respectively. The corresponding plasma concentrations were 14.1, 4.1, and 4 microg/ml. Therefore, brain versus plasma indomethacin level ratios were 2.5-fold higher after slow systemic input of indomethacin in comparison to rapid drug input. In conclusion, indomethacin brain uptake was found to be mode of administration-dependent, and a sustained input function increases the drug brain uptake. Thus, these unique results indicate that an appropriate indomethacin controlled release delivery system may induce the desirable brain-related pharmacodynamic effects, while avoiding the concentration-dependent adverse effects. These findings may contribute to improved therapy in Alzheimer's disease.

Indomethacin has been suggested for the treatment of Alzheimer's disease (AD), but its use is limited by gastrointestinal and renal toxicity. To overcome this limitation, D-Pharm Ltd. (Rehovot, Israel) developed DP-155 (mixture of 1-steroyl and 1-palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido] hexanoyl}-Sn-glycero-3-phosophatidyl [corrected] choline), a lecithin derivative of indomethacin. Safety was tested by daily oral administration of DP-155 or indomethacin to rats in a dose range of 0.007 to 0.28 mmol/kg. The prevalence of gastrointestinal ulceration was significantly lower (10-fold) for DP-155 than for indomethacin, and the ulcerations were delayed. Signs of renal toxicity, namely reduced urine output and increased urine N-acetyl glycosaminidase to creatinine ratio, were 5-fold lower for DP-155. Indomethacin, but not an equimolar dose of DP-155, reduced urine bicyclo-prostaglandin E(2). An equimolar oral dose of DP-155 or indomethacin, administered every 4 h for 3 days, was equally efficacious in reducing the levels of Abeta42 in the brains of Tg2576 mice. Indomethacin was the principal metabolite of DP-155 in the serum. After DP-155 oral administration, indomethacin's half-life in the serum and the brain was 22 and 93 h, respectively, compared with 10 and 24 h following indomethacin oral administration. The brain to serum ratio was 3.5 times higher for DP-155 than indomethacin. This finding explains the efficacy of DP-155 in reducing Abeta42 brain levels, despite the low systemic blood concentrations of indomethacin derived from DP-155. In conclusion, compared with indomethacin, DP-155 has significantly lower toxicity in the gut and kidney while maintaining similar efficacy to indomethacin in lowering Abeta42 in the brains of Tg2576 mice. This superior safety profile highlights DP-155's potential as an improved indomethacin-based therapy for AD.

Expandable gastroretentive dosage forms (GRDFs) have been designed for the past 3 decades. They were originally created for possible veterinary use, but later the design was modified for enhanced drug therapy in humans. These GRDFs are easily swallowed and reach a significantly larger size in the stomach due to swelling or unfolding processes that prolong their gastric retention time (GRT). After drug release, their dimensions are minimized with subsequent evacuation from the stomach. Gastroretentivity is enhanced by the combination of substantial dimensions with high rigidity of the dosage form to withstand the peristalsis and mechanical contractility of the stomach. Positive results were obtained in preclinical and clinical studies evaluating GRT of expandable GRDFs. Narrow absorption window drugs compounded in such systems have improved in vivo absorption properties. These findings are an important step towards the implementation of expandable GRDFs in the clinical setting. The current review deals with expandable GRDFs reported in articles and patents, and describes the physiological basis of their design. Using the dog as a preclinical screening model prior to human studies, relevant imaging techniques and pharmacokinetic-pharmacodynamic aspects of such delivery systems are also discussed.

Purpose. To design novel expandable gastroretentive dosage forms (GRDFs) and evaluate their gastroretentive properties. Then, to assess the pharmacokinetics of levodopa compounded in such a GRDF in healthy volunteers. Methods. Thin (