Chondroitin sulfate-based anti-inflammatory macromolecular prodrugs

Design, characterization and pharmaceutical/pharmacological applications of ibuprofen conjugates based on hydroxyethylcellulose

We synthesized polymeric prodrugs of ibuprofen (IBU) based on hydroxyethylcellulose (HEC) which offered extended release and enhanced bioavailability of IBU as well as significant immunomodulatory potential in cytokine release assay.

Synthesis, Bioevaluation and Molecular Dynamic Simulation Studies of Dexibuprofen-Antioxidant Mutual Prodrugs

Dexibuprofen–antioxidant conjugates were synthesized with the aim to reduce its gastrointestinal effects. The esters analogs of dexibuprofen 5a–c were obtained by reacting its –COOH group with chloroacetyl derivatives 3a–c. The in vitro hydrolysis data confirmed that synthesized prodrugs 5a–c were stable in stomach while undergo significant hydrolysis in 80% human plasma and thus release free dexibuprofen. The minimum reversion was observed at pH 1.2 suggesting that prodrugs are less irritating to stomach than dexibuprofen. The anti-inflammatory activity of 5c (p < 0.001) is more significant than the parent dexibuprofen. The prodrug 5c produced maximum inhibition (42.06%) of paw-edema against egg-albumin induced inflammation in mice. Anti-pyretic effects in mice indicated that prodrugs 5a and 5b showed significant inhibition of pyrexia (p < 0.001). The analgesic activity of 5a is more pronounced compared to other synthesized prodrugs. The mean percent inhibition indicated that the prodrug 5a was more active in decreasing the number of writhes induced by acetic acid than standard dexibuprofen. The ulcerogenic activity results assured that synthesized prodrugs produce less gastrointestinal adverse effects than dexibuprofen. The ex vivo antiplatelet aggregation activity results also confirmed that synthesized prodrugs are less irritant to gastrointestinal mucosa than the parent dexibuprofen. Molecular docking analysis showed that the prodrugs 5a–c interacts with the residues present in active binding sites of target protein. The stability of drug–target complexes is verified by molecular dynamic simulation study. It exhibited that synthesized prodrugs formed stable complexes with the COX-2 protein thus support our wet lab results. It is therefore concluded that the synthesized prodrugs have promising pharmacological activities with reduced gastrointestinal adverse effects than the parent drug.

A micelle-like structure of poloxamer-methotrexate conjugates as nanocarrier for methotrexate delivery

The purpose of this study was to develop a novel featured and flexible methotrexate (MTX) formulation, in which MTX was physically entrapped and chemically conjugated in the same drug delivery system. A series of poloxamer-MTX (p-MTX) conjugates was synthesized, wherein MTX was grafted to poloxamer through an ester bond. p-MTX conjugates could self-assemble into micelle-like structures in aqueous environment and the MTX end was in the inner-core of micelles. Moreover, free MTX could be physically entrapped into p-MTX micelles hydrophobic core region to increase the total drug loading. Importantly, the resulting MTX-loaded p-MTX micelles showed a biphasic release of MTX, with a relative fast release of the entrapped MTX (about 6-7h) followed by a sustained release of the conjugated MTX. The pharmacokinetics study showed that the mean residence time (MRT) was extended in the case of MTX-loaded p-MTX micelles, indicating a delayed MTX elimination from the bloodstream and prolonged in vivo residence time. Besides, the area under curve (AUC) of MTX-loaded p-MTX micelles was greater than free MTX, indicating a drug bioavailability improvement. Overall, MTX-loaded p-MTX micelles might be a promising nanosized drug delivery system for the cancer therapy.

A novel NSAID derivative, phospho-ibuprofen, prevents AOM-induced colon cancer in rats

The cancer chemopreventive properties and gastrointestinal toxicity of ibuprofen are well documented. Modification of existing NSAIDs has improved on the chemopreventive efficacy of this agent and reduced its toxicity. In this study, ibuprofen and a modified derivative (phospho-modified ibuprofen or p-ibuprofen) were used in a chemically induced model of colon cancer. Fisher 344 rats were injected with azoxymethane then treated with either ibuprofen (500 ppm) or p-ibuprofen (900 ppm) for 20 weeks to observe aberrant crypt foci (ACF) or 40 weeks to evaluate tumor incidence and multiplicity. β-catenin and p65 were measured in colonic tissues by immunofluorescence staining. Equal molar doses of ibuprofen (75 and 670 mg/kg) and p-ibuprofen (135 and 1,215 mg/kg) were administered to rats for 7 days to assess acute toxicity. The in vitro effect of p-ibuprofen on COX-2 and PGE(2) synthesis, β-catenin expression and NF-κB activity were examined in RAW 264.7 macrophage and HCT 116 colon cancer cells. At week 20, p-ibuprofen and ibuprofen significantly reduced the multiplicity of ACF compared with control (p<0.05); 31.2 and 37.9%, respectively. At week 40, p-ibuprofen and ibuprofen reduced the multiplicity of colon tumors compared with control (p<0.01) by 47.2 and 56.6%, respectively. Equal molar concentrations of ibuprofen (670 mg/kg) and p-ibuprofen (1,215 mg/kg) resulted in stomach ulceration in 85.7% (6 out of 7) and 14.3% (1 out of 7) of rats, respectively, with p<0.01. Immunofluoresence staining and western blot analysis demonstrated that both ibuprofen and p-ibuprofen suppressed β-catenin nuclear translocation in colon cancer cells. In addition, p-ibuprofen but not ibuprofen inhibited NF-κB activation in colon cancer cells. Collectively, these results suggest that p-ibuprofen is a potential effective novel drug for long-term use in colon cancer prevention.