Gemini Amphiphile-Based Lipoplexes for Efficient Gene Delivery: Synthesis, Formulation Development, Characterization, Gene Transfection, and Biodistribution Studies.

Some quaternary gemini amphiphiles (GAs) were synthesized as nonviral gene delivery carriers. The critical miceller concentration values of these amphiphiles are indicative of their superior surface-active properties. All of the synthesized GAs, alone or along with lipids like cholesterol and/or dioleoylphosphatidyl ethanolamine (DOPE), were formulated as liposomes. Formulations of GAs with DOPE showed average particle diameters of 326-400 nm with positive ζ-potential (30.1-46.4 mV). The lipoplexes of theses formulations showed complete pDNA retention at the base at a N/P ratio higher than 1.0 in gel retardation study. The GAs were effective in condensing pDNA into a ψ-phase, as indicated by circular dichroism study, and provided complete protection of the pDNA against the enzyme DNase at a N/P ratio more than 1. In vitro cell line studies showed that GA liposomal formulations caused ß-gal expression and offered a higher transfection efficiency than that of liposomes prepared with the help of N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP)/DOPE and dicyclocarbodiimide (DCC)/DOPE but comparable to those of Lipofectamine 2000 in A549 and HeLa cell lines. Modulation of head group polarity significantly affected the transfection efficacy of GAs. The cell viabilities of almost all of the formulations were comparable to those of the standards (DCC/DOPE and DOTAP/DOPE liposomes). Incorporation of cholesterol [GA/DOPE/cholesterol in the ratio of 1:1:1] further improved the serum compatibility of the formulations and improved the transfection efficacy when evaluated in A549 and HeLa cell lines. Fluorescence-assisted cell sorting studies showed comparable number of transfected cells to Lipofectamine 2000 in the HeLa cell line. Intracellular trafficking studies using confocal microscopy indicated transfection of the HeLa cells with the reporter gene within 30 min of lipoplex treatment. γ-Scintigraphy using 99mTc-labeled lipoplexes showed higher concentrations of the lipoplexes in vital tissues like liver, spleen, lungs, and kidneys.

Advances in the Development of Novel Factor Xa Inhibitors: A Patent Review.

Development of new anticoagulants has been in constant demand throughout the world due to increasing rate of morbidity and mortality caused by thrombotic diseases. Factor Xa (FXa), one of the enzymes and validated target for anticoagulation, regulates the production of thrombin in the coagulation cascade. The importance of oral FXa inhibitors like rivaroxaban, apixaban and edoxaban in thromboembolic conditions is well supported by increasing number of patents and research publications during the recent years. Direct FXa inhibitors as antithrombotic agents offer selective, efficacious and orally active therapy with respect to the other traditional anticoagulants. Newly developed patented molecules are mainly structural bioisosteres of existing drugs and have exhibited better efficacy and safety profile. Development of antidotes for oral direct FXa inhibitors is in pipeline and their expected approval for therapeutic purposes will be further beneficial to anticoagulation therapy. This review is mainly focused on industrial and academic patents on the discovery of direct FXa inhibitors. The review covers patented compounds from December 2011 till date, describing various structural modifications along with biological activity data and advances in the process and formulation technologies of the reported FXa inhibitors.

Retraction of "novel 2-aminobenzamides as potential orally active antithrombotic agents".

[This retracts the article DOI: 10.1021/ml300217f.].

Falcipain inhibitors as potential therapeutics for resistant strains of malaria: a patent review.

INTRODUCTION: There is an urgent need to discover new antimalarial drugs due to emergence of resistance in the parasite to the existing drugs. Malarial cysteine proteases falcipin-2 (FP-2) and falcipain-3 (FP-3) are attractive targets for antimalarial chemotherapy. The structures and functions of FP-2/3, their binding domains and their interactions with small- and macro-molecules are well studied. These studies could provide important insight into rational designing of FP inhibitors as potential antimalarial drugs. AREAS COVERED: This review is focused on a selection of interesting patents published during 1999 - 2011 on peptidic and nonpeptidic chemotypes of the FP-2/FP-3 inhibitors. EXPERT OPINION: It is a known fact that malaria is a serious health problem worldwide due to the emergence of resistant strains. Hence, development of novel, potent and affordable antimalarial drugs devoid of side effects is of great significance and in great demand. FPs, the malarial cysteine proteases are potential targets for development of new antimalarial drugs. Assessing the available literature on FP-2/3 and their inhibitors it could be speculated that these inhibitors have the potential to enter the clinical stages of development for the treatment of malaria in the years to come.

Novel 2-aminobenzamides as potential orally active antithrombotic agents.

In an effort to develop potent antithrombotic agents, a series of novel 2-aminobenzamide derivatives were synthesized and screened for their in vivo antithrombotic activity. Among the 23 compounds tested, compound (8g) showed the most promising antithrombotic activity, which was comparable with clinically used aspirin or warfarin, but at variance with these standard drugs, 8g did not exhibit the increased bleeding time, suggesting its potential as a novel antithrombotic agent.

Cytotoxic potential of novel 6,7-dimethoxyquinazolines.

Herein, we report the synthesis and cytotoxicity of a series of substituted 6,7-dimethoxyquinazoline derivatives. The cytotoxic activity of all synthesized compounds has been evaluated against HCT116p53(+/+) and HCT116p53(-/-) colon cancer cells and a HEY ovarian cancer cell line naturally resistant to cisplatin. Nine of the tested compounds showed significant cytotoxicity in all cell lines at 10µM. The most promising derivative (7c) showed IC(50)values of 0.7 and 1.7µM in the two colon cancer cell lines.

QSAR studies on 4-quinolone derivatives as high-affinity ligands at the benzodiazepine site of brain GABA(A) receptors.

Quantitative structure activity relationship approach using stepwise regression analysis was applied to a series of 4-quinolone derivatives as high-affinity ligands at the benzodiazepine site of brain GABA(A) receptors. For the purpose 25 compounds were used to develop models. Statistically significant equations were obtained with high squared correlation coefficient (r(2)=0.8761, 0.9295 and 0.8705) and low root mean square error (RMSE=0.4844, 0.3894 and 0.4952). The robustness of the model was confirmed with the help of leave one out cross validation method which exhibited high r(2)(cv) values (r(2)(cv)=0.7875, 0.8263 and 0.7927). A good correlation of various molecular shape parameters, like ovality, Szeged index, and energy of the molecule with the GABA(A) affinity was achieved.

Peptidomimetic 2-cyanopyrrolidines as potent selective cathepsin L inhibitors.

Cathepsins have been found to have important physiological roles. The implication of cathepsin L in various types of cancers is well established. In a search for selective cathepsin L inhibitors as anticancer agents, a series of 2-cyanoprrolidine peptidomimetics, carrying a nitrile group as warhead, were designed. Two series of compounds, one with a benzyl moiety and a second with an isobutyl moiety at P(2) position of the enzyme were synthesized. The synthesized compounds were evaluated for inhibitory activity against human cathepsin L and cathepsin B. Although, none of the compounds showed promising inhibitory activity, (E)N-{(S)1-[(S)2-cyano-1-pyrrolidinecarbonyl]-3-methylbutyl}-2,3-diphenylacrylamide (24) with an isobutyl moiety at P(2) was found to show selectivity as a cathepsin L inhibitor (Ki 5.3 microM for cathepsin L and Ki > 100 microM for cathepsin B). This compound could act as a new lead for the further development of improved inhibitors within this inhibitor type.

Combining anticholinergic and anti-inflammatory activities into a single moiety: a novel approach to reduce gastrointestinal toxicity of ibuprofen and ketoprofen.

With the aim of reducing the local gastric irritation associated with non-steroidal anti-inflammatory drugs, a series of N,N-disubstituted aminoalcohol ester derivatives of ibuprofen and ketoprofen were synthesized and evaluated. The esters were specially designed to possess the anticholinergic activity in the intact form and exhibit the anti-inflammatory action after hydrolysis to the respective parent drug. The rationale being that besides blocking the acidic carboxylic group of the parent drug, the existence of the anticholinergic effect in the intact molecule would further aid in reducing the gastrointestinal mucosal damage by decreasing the gastric secretions and motility. All the ester derivatives were found to be stable in acidic and basic buffers. The synthesized derivatives, with experimentally proven good anti-inflammatory and anticholinergic activities, showed significant reduction of ulcerogenicity in the stomach. These results are attributed to the acquired anticholinergic activity with a simultaneous reduction of acidic character compared to the parent compounds. The study offers a new strategy for design and development of compounds with safer therapeutic profile for long-term treatment of inflammation-associated disorders.

Synthesis and evaluation of some gastrointestinal sparing anti-inflammatory aminoethyl ester derivatives of naphthalene-based NSAIDs.

To overcome the local gastric toxicity associated with use of common non-steroidal anti-inflammatory drugs (NSAIDs), some aminoalcohol esters of NSAIDs bearing structural resemblance to the aminoalcohol ester class of anticholinergics were specially designed and synthesized. Besides blocking the acidic carboxyl group to overcome the local gastric irritation, the anticholinergic activity was incorporated with the expected advantage of reducing the gastric toxicity by decreasing gastric acid secretions and motility. Derivatives of naproxen and 6-methoxy-2-napthylacetic acid (6-MNA) were synthesized. The hydrolysis studies in buffers revealed the majority of the compounds to be sufficiently stable with a high enzymatic susceptibility in 80% human serum. Most of the derivatives exhibited a fairly good anticholinergic action against acetylcholine with a significant reduction in ulcerogenicity while retaining the anti-inflammatory potency of the parent drug. The combination of anti-inflammatory and anticholinergic activities, with a simultaneous reduction of the acidic character, may lead to development of therapeutically better compounds than the parent NSAIDs for long-term oral anti-inflammatory therapy.