The cannabinoid CB1 receptor is involved in complex physiological functions. The discovery of CB1 allosteric modulators generates new opportunities for drug discovery targeting the pharmacologically important CB1 receptor. 5-chloro-3-ethyl-N-(4-(piperidin-1-yl)phenethyl)-1H-indole-2-carboxamide (ORG27569; 1) represents a new class of indole-2-carboxamides that exhibit allostery of CB1. To better understand the SAR, a group of indole-2-carboxamide analogs were synthesized and assessed for allostery of the CB1 receptor. We found that within the structure of indole-2-carboxamides, the presence of the indole ring is preferred for maintaining the modulator's high binding affinity for the allosteric site, but not for generating allostery on the orthosteric site. However, the C3 substituents of the indole-2-carboxamides significantly impact the allostery of the ligand. A robust CB1 allosteric modulator 5-chloro-N-(4-(dimethylamino)phenethyl)-3-pentyl-1H-indole-2-carboxamide (11j) was identified. It showed an equilibrium dissociation constant (KB) of 167.3 nM with a markedly high binding cooperativity factor (α=16.55) and potent antagonism of agonist-induced GTPγS binding.

Allosteric modulation of G-protein coupled receptors (GPCRs) represents a novel approach for fine-tuning GPCR functions. The cannabinoid CB1 receptor, a GPCR associated with the CNS, has been implicated in the treatment of drug addiction, pain, and appetite disorders. We report here the synthesis and pharmacological characterization of two indole-2-carboxamides: 5-chloro-3-ethyl-1-methyl-N-(4-(piperidin-1-yl)phenethyl)-1H-indole-2-carboxamide (ICAM-a) and 5-chloro-3-pentyl-N-(4-(piperidin-1-yl)phenethyl)-1H-indole-2-carboxamide (ICAM-b). While both ICAM-a and ICAM-b enhanced CP55,940 binding, ICAM-b exhibited the strongest positive cooperativity thus far demonstrated for enhancing agonist binding to the CB1 receptor. Although it displayed negative modulatory effects on G-protein-coupling to CB1, ICAM-b induced β-arrestin-mediated downstream activation of ERK signaling. These results indicate that this compound represents a novel class of CB1 ligands that produce biased signaling via CB1.

Bortezomib is the first proteasome inhibitor approved for the therapy of multiple myeloma (MM) based on its in vitro and in vivo activity in myeloma. However, the toxicity and effects of this drug on the human immune function have not been entirely studied. In the present study, we evaluated the effects of Bortezomib on normal human immune cells including dendritic cells (DC), T lymphocytes and NK cells for cell survival, antigen expression, production of cytokines, and other key parameters of immune cell function. In our evaluation of effect of Bortezomib on DC, we did not observe significant change in the expression of cell surface antigens including CD40, CD80, CD83, CD86, HLA-ABC and HLA-DPQR molecules in terms of percentage of cells positive as well as mean fluorescence intensity (MFI). Bortezomib treated immature DC maintained the ability for antigen uptake as measured by uptake of Dextran-FITC (untrt vs. trt = 798 MFI vs. 802 MFI), maintained the expression levels of antigen uptake receptors including mannose (untrt vs. trt = 85% vs. 79%) and DEC-205 (untrt vs. trt = 49% vs. 42%), and the capacity to produce IL-12 (untrt vs. trt = 135 vs. 125 pg/ml). In addition, Bortezomib treated mature DC was able to induce comparable levels of allogenic T cell proliferation to the untreated mature DC as measured by 3[H]-Thymidine incorporation (untrt vs. trt = 212556 cpm vs. 220571 cpm). Furthermore, cell surface antigen expression including CD3, CD4, CD8, CD28, CD154 (CD40L) and TCRab on T lymphocytes were not changed by Bortezomib treatment. The treated T cells also maintained the ability to secrete IFN-g secretion in response to allogenic DC (untrt vs. trt = 85 vs. 88 pg/ml) or Staphylococcal enterotoxin B (untrt vs. trt = 131 vs. 154 pg/ml). The cytolytic activity of the NK cell population was comparable between proteasome inhibitor treated and untreated control cells against the McCAR (untrt vs. trt = 44% vs. 52%) and MM1S (49% vs. 42%) target MM cell lines. This observation was correlated with similar expression levels of CD2, CD11a, CD94, NKp30, NKp44, NKp46, and KARp50.3 activation antigens in treated versus untreated NK cells. These, in vitro results confirm lack of adverse effects of Bortezomib on immune function, and allow us to incorporate of Bortezomib in multimodality therapy that includes immunotherapy.

This study is aimed to develop and evaluate cost-effective cellulose acetate (CA)-polyvinyl pyrrolidone (PVP) film coating that can effectively control the release of freely water soluble drug, metoprolol succinate (MS) and to match that of release profile with its marketed tablet formulation. Simple core tables of MS were compressed and coated with a solution composed of semipermeable rate controlling polymer, CA and water soluble pore forming polymer, PVP. Drug-excipient interaction was investigated by both physical observation and differential scanning calorimetry (DSC). The effect of formulation parameters such as the ratio of CA to PVP, tablet coating weight gain, effect of pH on the in-vitro drug release were evaluated. Surface morphology of the CA coating membrane was examined by scanning electron microscope (SEM). Release profile of the optimized formulation at different pH conditions was determined and the similarity factor (f2) with marketed tablet release profile was calculated. It was observed that drug release rate increased with a decrease in the ratio of cellulose acetate to PVP and decreased with increased weight gain of the coating membrane. Among all the formulations, the formulation with CA and PVP at a ratio of 85:15 %w/w and 9 % weight gain showed matching release profile to the marketed tablet formulation with f2 value of 72.25. Developed MS formulation showed pH independent drug release. This study proved that CA-PVP polymer coating could effectively control the release rate of freely water soluble drugs for up to 24 h. Once a day CR formulation of metoprolol succinate pharmaceutically equivalent to marketed formulation was developed.