Mutual Prodrug Research Articles

Synthesis of new Conjugates of some NSAIDs with Sulfonamide as Possible Mutual Prodrugs using Tyrosine Spacer for Colon Targeted Drug Delivery

The purpose of this research work is to synthesize conjugates of some NSAIDs with sulfamethoxazole as possible mutual prodrugs to overcome the local gastric irritation of NSAID with free carboxyl group by formation of ester linkage that supposed to remain intact in stomach and may hydrolyze in intestine chemically or enzymatically; in addition to that attempting to target the synthesized derivative to the colon by formation of azo group that undergo reduction only by colonic bacterial azo reductaze enzyme to liberate the parent compound to act locally (treatment of inflammation and infections in colon).
 Key words: Mutual prodrug, Ester linkage, Azo bond, Colon targeting

Design, Synthesis and Kinetic Study of Coumarin-Based Mutual Prodrug of 5-Fluorouracil and Dichloroacetic acid

On the basis of known coumarin-based prodrug system, a novel coumarin-based mutual prodrug of 5-fluorouracil and dichloroacetic acid was designed, synthesized and evaluated as a promising oral chemotherapeutic agent basing on in vitro stability study in HCl buffer (pH 1.2) and in phosphate buffer (pH 7.4), as well as in vitro release study in human serum. The chemical structure of prodrug was confirmed by analyzing its FTIR, 1H NMR, 13C NMR and MS-ESI spectra. The results of in vitro kinetic study indicated that the prodrug was significantly stable in HCl and in phosphate buffers, and was hydrolyzed in human serum followed pseudo first order kinetics.
 Keywords: Coumarin-based prodrug, 5-fluorouracil, Dichloroacetate, kinetics.

Synthesis and evaluation of novel mutual prodrugs of Piroxicam

Therapeutic efficacy of piroxicam can be improved by retarding gastrointestinal side effects by means of temporarily modification of enolic hydroxyl group chemically. The NSAIDs such as aceclofenac, ibuprofen, mefenamic acid and naproxen were selected as promoities with the aim of getting synergistic effect through these well known pharmaco-counter parts. The targeted prodrugs are synthesized successfully and confirmed by characterization. Synthesis involved chlorination of NSAIDs and coupling of this acid chloride with piroxicam through enolic hydroxyl group to get ester derivatives. Mutual prodrugs were evaluated by hydrolysis study at different pH (acidic, neutral, alkaline) using phosphate buffer. Prodrug derivatives were found to be stable at acidic and neutral pH but prone to hydrolysis at alkaline pH. Thus the objective of the presented study was to overcome the undesirable side effects of NSAIDs. Thus, current studies confirms that the mutual prodrug approach can be applied effectively in order to achieve the purpose of raising effectiveness of piroxicam under two lines; firstly, masking of enolic hydroxyl group through acids and converting them to esters and secondly, utilizing the known NSAIDs for achieving the synergistic effect.

Design, Synthesis and Hydrolysis Study of Gatifloxacin-NSAIDs as Mutual Prodrugs

Design, Synthesis and Hydrolysis Study of Gatifloxacin-NSAIDs as Mutual Prodrugs

Discovery of a novel chimeric ubenimex–gemcitabine with potent oral antitumor activity

Herein, a novel mutual prodrug BC-A1 was discovered by integrating ubenimex and gemcitabine into one molecule. Biological characterization revealed that compound BC-A1 could maintain both the anti-CD13 activity of ubenimex and the cytotoxic activity of gemcitabine in vitro. Further characterization also demonstrated that compound BC-A1 exhibited significant anti-invasion and anti-angiogenesis effects in vitro. The preliminary stability test of BC-A1 revealed that it could release gemcitabine in vitro. The in vivo anti-tumor results in liver cancer showed that at the same dosage, oral administration of BC-A1 was as potent as intraperitoneal administration of gemcitabine. This warranted the further research and development of the orally active prodrug BC-A1 because gemcitabine can not be orally administrated in clinic.

Flurbiprofen-antioxidant mutual prodrugs as safer nonsteroidal anti-inflammatory drugs: synthesis, pharmacological investigation, and computational molecular modeling.

Flurbiprofen–antioxidant mutual prodrugs were synthesized to reduce the gastrointestinal (GI) effects associated with flurbiprofen. For reducing the GI toxicity, the free carboxylic group (–COOH) was temporarily masked by esterification with phenolic –OH of natural antioxidants vanillin, thymol, umbelliferone, and sesamol. The in vitro hydrolysis of synthesized prodrugs showed that they were stable in buffer solution at pH 1.2, indicating their stability in the stomach. The synthesized prodrugs undergo significant hydrolysis in 80% human plasma and thus release free flurbiprofen. The minimum reversion was observed at pH 1.2, suggesting that prodrugs are less irritating to the stomach than flurbiprofen. The anti-inflammatory, analgesic, antipyretic, and ulcerogenic activities of prodrugs were evaluated. All the synthesized prodrugs significantly (P<0.001) reduced the inflammation against carrageenan and egg albumin-induced paw edema at 4 hours of study. The reduction in the size of the inflamed paw showed that most of the compounds inhibited the later phase of inflammation. The prodrug 2-oxo-2H-chromen-7-yl-2-(2-fluorobiphenyl-4-yl)propanoate (4b) showed significant reduction in paw licking with percentage inhibition of 58%. It also exhibited higher analgesic activity, reducing the number of writhes with a percentage of 75%, whereas flurbiprofen showed 69% inhibition. Antipyretic activity was investigated using brewer’s yeast-induced pyrexia model, and significant (P<0.001) reduction in rectal temperature was shown by all prodrugs at all times of assessment. The results of ulcerogenic activity showed that all prodrugs produced less GI irritation than flurbiprofen. Molecular docking and simulation studies were carried out with cyclooxygenase (COX-1 and COX-2) proteins, and it was observed that our prodrugs have more potential to selectively bind to COX-2 than to COX-1. It is concluded that the synthesized prodrugs have promising pharmacological activities with reduced GI adverse effects than the parent drug.

Discovery of BC-01, a novel mutual prodrug (hybrid drug) of ubenimex and fluorouracil as anticancer agent

We designed and synthesized a novel mutual prodrug, named BC-01 (3), by integrating ubenimex and Fluorouracil (5-FU) into one molecule based on prior research results that showed that a combination of the aminopeptidase N (CD13) inhibitor, ubenimex, and the cytotoxic antitumor agent, 5-FU, exhibited improved in vitro and in vivo antitumor efficiency. 3 showed potent inhibitory activity against CD13 enzymatic activity. Compared with ubenimex, 3 exhibited more potent anti-angiogenesis effects, and compared with the approved 5-FU prodrug, capecitabine, 3 exhibited more potent tumor growth inhibitory and anti-metastasis effects. Additionally, compared with 5-FU or 5-FU plus ubenimex, 3 also exhibited a superior antitumor efficiency even in our 5-FU-resistant mice model. Other antitumor agents could be conjugated with ubenimex using this strategy to obtain novel mutual prodrugs with promising antitumor potency.

5-Aminosalicylic Acid Azo-Linked to Procainamide Acts as an Anticolitic Mutual Prodrug via Additive Inhibition of Nuclear Factor kappaB.

To improve the anticolitic efficacy of 5-aminosalicylic acid (5-ASA), a colon-specific mutual prodrug of 5-ASA was designed. 5-ASA was coupled to procainamide (PA), a local anesthetic, via an azo bond to prepare 5-(4-{[2-(diethylamino)ethyl]carbamoyl}phenylazo)salicylic acid (5-ASA-azo-PA). 5-ASA-azo-PA was cleaved to 5-ASA and PA up to about 76% at 10 h in the cecal contents while remaining stable in the small intestinal contents. Oral gavage of 5-ASA-azo-PA and sulfasalazine, a colon-specific prodrug currently used in clinic, to rats showed similar efficiency in delivery of 5-ASA to the large intestine, and PA was not detectable in the blood after 5-ASA-azo-PA administration. Oral gavage of 5-ASA-azo-PA alleviated 2,4,6-trinitrobenzenesulfonic acid-induced rat colitis. Moreover, combined intracolonic treatment with 5-ASA and PA elicited an additive ameliorative effect. Furthermore, combined treatment with 5-ASA and PA additively inhibited nuclear factor-kappaB (NFκB) activity in human colon carcinoma cells and inflamed colonic tissues. Finally, 5-ASA-azo-PA administered orally was able to reduce inflammatory mediators, NFκB target gene products, in the inflamed colon. 5-ASA-azo-PA may be a colon-specific mutual prodrug acting against colitis, and the mutual anticolitic effects occurred at least partly through the cooperative inhibition of NFκB activity.

Synthesis and biological evaluation of a mutual prodrug of norfloxacin and fenbufen

Abstract Objectives The study aimed to synthesize a mutual prodrug of norfloxacin and fenbufen with an objective of obtaining an effective and safer anti-inflammatory drug with useful antimicrobial actions. Methods An amide-based mutual prodrug ( NF-FN ) was prepared following a single-step synthesis by condensing norfloxacin with fenbufen under appropriate laboratory conditions. Its structure was established on the basis of IR, NMR, Mass spectral data and elemental analysis. The prodrug ( NF-FN ) was evaluated for in-vitro antibacterial activity against two gram positive ( Staphylococcus aureus & Bacillus subtilis ) and two gram negative bacterial strains ( Escherichia coli & Klebsiella pneumonia ). The in-vivo anti-inflammatory activity and ulcerogenicity of the synthesized prodrug were investigated in Wistar albino rats at the doses of 10 and 30 mg/kg body weight, respectively. Results The synthesized prodrug ( NF-FN ) showed very good activity against S. aureus & E. coli with MIC -6.25 μg/mL, and good activity against B. subtilis & K. pneumonia with MIC -12.5 μg/mL. Its anti-inflammatory activity was found to be better than that of the parent drug fenbufen. It was also observed to less severe on gastric mucosa in comparison to reference drug, fenbufen. Conclusion The prodrug showed promising results as anti-inflammatory agent however, its antibacterial action was found to be slightly weaker than the other parent drug norfloxacin.

Synthesis of codeine derivative as –a prod rug and study its effect on some biochemical parameters on rabbits

The codeine was used as carrier of alcohol to attach with non-steroidal anti-inflammatory Drug (aspirin ). The present work is aimed to synthesize the esterification reaction of (OH) group of codeine with aspirin as (acid chloride) which yielded the corresponding aspirin ester . The purity of the synthesized compounds were established by (TLC) and column chromatography , while the structures of their mutual prod rug was confirmed by (FTIR, 1HNMR,13CNMR) The results obtained give a good evidence for proposed structures to their compounds. The study included 30 rabbits with the same weights thy divided into three groups(ten rabbits for each group). First was a control group which did not have any dose, the second group has aspirin (0.099gm/kg) and codiene (0.07 gm/kg) dose ,and the third group contained the prepared derivative (0.159gm/kg)dose that equivalent with the dose of the second group. samples of blood have been takes from each rabbit, after three hours and serum has been separated to use in the study of the following parameter . The measured parameters include :the activity of (Lactate dehydrogenase(LDH) , Cholenestrase, creatinkinase (MB) ,Alkaline phosphatase(ALP) , alamine amino transaminase (ALT) , aspartae amino transaminase (AST) , cholinesterase and peroxidase) , and the concentrations of ( Cholestrol ,try clysride (T.G) , albumin and total protein ) and in addition to lipoproteins ( HDL , LDL, vLDL ) .and the concentration of total focus ,protein bounding focus and protein bounding hexsose. To ensure the release of pro drugs (Aspirin, codiene) a hydrolytic study of their esters were done at different pH [ 2 , 4 , 8 ,10 ] at constant temperature (25 C0) ,The results indicated that the hydrolysis at basic pH were faster than acidic pH which means that the most hydrolysis will be obtained at intestine and not in the stomach

Design, Synthesis and In Vitro Release Studies of Co-Drugs for Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease that results in a chronic, systemic inflammation that may affect many tissues and organs, but principally the synovial joints. The tendency for joint destruction is greatest in the early stages of disease hence current trend is to introduce a disease-modifying anti-rheumatic drug (DMARD) immediately after the diagnosis of RA in a step- up approach which is generally followed by its combination with a corticosteroid or NSAID. Hydroxychloroquine (HCQ) is a slow acting DMARD used in the early stage of RA. NSAIDs if given in combination with HCQ would provide immediate symptomatic relief from pain and inflammation even before HCQ starts showing its disease modifying effects. Long half life of HCQ results in its accumulation in the body while frequent intake of NSAIDs results in severe GI side effects. Present project aims at minimizing these shortcomings by designing co-drugs of HCQ and NSAIDs as a potential combination RA therapy. Synthesis of two co-drugs was achieved by CDI coupling, followed by their spectral characterization. In vitro release kinetics was studied by HPTLC in aqueous buffers and tissue homogenates of upper GIT. Prodrugs were resistant to hydrolysis in buffers (pH 1.2 and 7.4) and stomach homogenates of Wistar rat but 32- 65% hydrolysis was observed in small intestinal homogenates. We propose that the mutual prodrug strategy of a DMARD with NSAID could be useful in initial management of RA wherein NSAIDs would produce their anti-inflammatory effect and simultaneously the process of joint reconstruction by hydroxychloroquine could be initiated.

Formulation and evaluation of co-prodrug of flurbiprofen and methocarbamol

The current work envisages synthesis of an ester prodrug of flurbiprofen whereby its carboxylic group was condensed with a skeletal muscle relaxant methocarbamol, with the aim of synergistic activity of two drugs, avoid flurbiprofen mediated gastro-intestinal damage and minimize the ulceration tendency of flurbiprofen. The synthesized prodrug was characterized and confirmed by physicochemical and spectroscopic studies. Solubility and partition coefficient studies indicated an increased lipophilicity and thus better suitability for oral administration than the parent drugs and the protein binding studies revealed a low protein binding capacity of the mutual prodrug. Subsequently, in-vitro hydrolysis was studied in different pH, simulated gastric fluid, simulated intestinal fluid and plasma and quantitative evaluation was performed by high performance liquid chromatography. It was found that the prodrug remained unhydrolyzed in the stomach after absorption however, underwent rapid cleavage by the esterases in blood to give the parent drug. Furthermore, the mutual ester prodrug was evaluated for its anti-inflammatory, analgesic, skeletal muscle relaxation, ulcerogenic and total acid content activity and was found to possess comparable activity with that of the parent drugs. Microscopic structures of the stomach tissues revealed significant reduction in gastric ulcer formation of mice gastric mucosa as compared to parent carboxylic acid drug.

Mono- and combined antimicrobial agents efficiency in experimental wound infection

Modern problems of antibiotic therapy are shown by wide range of side effects, both on organism and microbiological levels: the spread of allergies, toxic for organ systems reactions, dysbiosis development, and resistant pathogens formation and dissemination. Therefore the necessity of search for new effective drugs with significant antimicrobial activity applied for the wounds treatment arises. Development of combined remedies on the background of different origin antimicrobial agents’ derivatives is one of the fight directions against infectious diseases in the skin pathology. Recently among the existing antimicrobial agents one should focus on antiseptic drugs, due to degenerative and dysfunctional effect on microbial cell.Aim of research. The comparison of mono- and combined antimicrobial agents chemotherapeutic efficiency in the treatment of localized purulent infection under experimental conditions.Metods. The study of chemotherapeutic efficiency was carried out on the model of localized purulent Staphylococcus infection on albino mice weighting 14 – 16 g. S.aureus ATCC 25923 strains were used as infectious agents. The contamination was performed subcutaneously to the right side of mice’s skin after depilation. The animals were randomly divided into 4 groups: the 1st group – infected mice without treatment (control); the 2nd group – infected mice treated with a ciprofloxacin; the 3rd group – infected mice treated with a Ciprofloxacin and Decamethoxin combination; the 4th group – infected mice treated with a combined drug on the base of mutual prodrugs (Hexamethylenetetramine and Phenyl salicylate).Results. The efficiency of mono- and combined antimicrobial agents under experimental Staphylococcus wound infection conditions was studied. It was found that localized purulent staph center was formed more slowly in comparison with control and mono preparation use (2nd group of animals). The average index of skin lesions in comparison with control and 2nd groups’ data (33 and 24) amounted to 6,4 in the 3rd group and 6,2 in the 4th group per animal respectively. The use of combined remedies №1 and №2 accelerated the recovery periods at 2,2 and 2,8 times in comparison with control group.Conclusion. It was found that the most effective treatment of animals with localized Staphylococcus infection was when used in Ciprofloxacin and Decamethoxin combination, and antiseptics with Salol-dependent principle of action combination.It was proved that on the pre-clinical modeling of localized purulent infection level suggested combinations show satisfactory therapeutic and preventive properties

Synthesis and pharmacological evaluation of mutual prodrugs of aceclofenac with quercetin, vanillin and l-tryptophan as gastrosparing NSAIDS

Synthesis, physicochemical characterization and pharmacological evaluation of mutual prodrugs of aceclofenac with quercetin, vanillin and l-tryptophan have been attempted to develop novel gastrosparing NSAIDs, devoid of ulcerogenic side effects. The structures of synthesized prodrugs were confirmed by IR, 1H NMR, 13C NMR and mass spectroscopy. The hydrolysis kinetics studies were performed in simulated gastric fluid, simulated intestinal fluid and rat fecal matter. Its anti-inflammatory and ulcer index were analyzed along with estimation of biochemical parameters (GWM and Hexosamine), oxidative parameters (LPO, GSH, CAT, and SOD) and protein estimation. The results indicated that the synthesized prodrugs are chemically stable, biolabile and possesses optimum lipophilicity. They also exhibited retention of anti-inflammatory activity with reduced ulcerogenicity. The study showed that the mutual prodrugs are better in action compared to the parent drug and have fewer gastrointestinal side effects.

Synthesis and Biological Evaluation of Novel Cholesterol Lowering Agents

Propitious hypolipidemic activity has been reported in droves of 2- substitutedthieno(2,3-d)pyrimidines. Earlier 2-(chloromethyl)-5,6,7,8-tetrahydro(1) benzothieno(2,3-d)pyrimidin-4(3H)-one (I, LM-1554, CAS89567-03-3) have been extensively evaluated pharmacologically and toxicologically for hypolipidemic activities. Its 4-chloro analog (II) recently revealed much supercilious activity to it. Scientific exploration and clinical studies have already archieved the importance of Niacin (Vitamin B3) in reducing blood cholesterol levels and other consequential risk factors in the blood. Further, it also documented to contribute in the repair of artery wall. With this rationalization, the synthesis & biological evaluation of novel mutual prodrugs composing the LM 1554 nucleus and vitamin B3 molecule was ventured through the consecutive synthetic routes.

Evaluation of glycine-bearing celecoxib derivatives as a colon-specific mutual prodrug acting on nuclear factor-κB, an anti-inflammatory target.

In an inflammatory state where HOCl is generated, glycine readily reacts with HOCl to produce glycine chloramine, an anti-inflammatory oxidant. Colonic delivery of celecoxib elicits anticolitic effects in a trinitrobenzene sulfonic acid-induced rat colitis model. Glycine-bearing celecoxib derivatives were prepared and evaluated as a colon-specific mutual prodrug acting on nuclear factor-κB (NFκB), an anticolitic target. Glycylcelecoxib (GC), N-glycylaspart-1-ylcelecoxib (N-GA1C), and C-glycylaspart-1-ylcelecoxib (C-GA1C) were synthesized and their structures identified using infrared and proton nuclear magnetic resonance spectrometer. The celecoxib derivatives were chemically stable in pH 6.8 and 1.2 buffers. GC and C-GA1C were resistant to degradation in the small intestinal contents, while N-GA1C was substantially cleaved to release celecoxib. In contrast, all the celecoxib derivatives were degraded to liberate celecoxib in the cecal content. These results suggest that GC and C-GA1C could be delivered to and liberate celecoxib and glycine in the large intestine. In human colon carcinoma HCT116 and murine macrophage RAW264.7 cells, combined celecoxib–glycine chloramine treatment additively suppressed the production of proinflammatory NFκB target gene products. Collectively, our data suggest that C-GA1C is a potential colon-specific mutual prodrug acting against NFκB.

Diacerein-thymol prodrug: in vivo release and pharmacological screening in experimental models of osteoarthritis in Wistar rats.

We have reported the synthesis, characterization, in vitro release profile and preliminary pharmacological investigations of an antioxidant mutual prodrug of diacerein with thymol in our earlier communication. The present work reports the results of in vivo release studies and extensive pharmacological evaluation of this prodrug in collagenase- induced osteoarthritis and monosodium iodoacetate- induced hyperalgesia in Wistar rats. In vivo release was thoroughly studied in Wistar rats upon oral administration of the prodrug. In rat blood, release of 92.7% of diacerein and 20.5% of thymol was observed. From these studies we hypothesized that activation of prodrug could be mediated by physiological pH of blood (7.4) and serum esterases. Pharmacological screening of prodrug in collagenase and monoiodoacetate-induced osteoarthritis at a dose of 6.8 mg/kg, (BID) exhibited significant reduction in knee diameter (p<0.001), increase in paw withdrawal latency (p<0.001), and locomotor activity (p<0.001) with significantly higher anti-inflammatory and anti-osteoarthritic activities as compared to parent drug. The biochemical studies indicated a significant step-up in glucosaminoglycan level (p<0.001) and reduction in the C-reactive protein (p<0.001) and sulfated alkaline phosphatase levels (p<0.001). The histopathological and radiological studies confirmed the additive anti-osteoarthritic effect of prodrug as compared to plain diacerein. Antioxidant potential of prodrug was significantly more (p<0.001) while ulcer index was significantly lower (p<0.01) than diacerein. Interestingly, the diarrhea observed in diacerein- treated animals was not evident in animalstreated with prodrug, thymol and their physical mixture. Our findings indicate promising potential of this antioxidant prodrug to be used for long-term and safer management of OA.

Synthesis, hydrolysis kinetics and pharmacological evaluation of aceclofenac prodrugs.

The mutual prodrugs of aceclofenac with various naturally available antioxidants; menthol, thymol, eugenol, guiacol and vanillin have been synthesized by the DCC coupling method, purified and characterized by spectral data, as well as, partition coefficient, solubility and hydrolytic studies. The title compounds have more lipophilic character as compared to the parent moieties and good stability in acidic environment, which is prerequisite for the oral absorption of the drug. Under gastric as well as intestinal pH conditions these prodrugs showed variable susceptibility towards hydrolysis. The synthesized derivatives were evaluated for antiinflammatory, analgesic activities and ulcerogenic potential. Prodrug showed improved solubility in organic solvents, which implies lipophilic character of ester prodrugs and were also found to be chemically stable in acidic environment. The aceclofenac mutual prodrugs showed improved analgesic and anti-inflammatory activities with reduced ulcerogenicity.

NALIDIXIC ACID MUTUAL PRODRUG: SYNTHESIS AND EVALUATION

The aim of this study has been to design a useful drug, which may act with effectiveness both on the gram-positive and gram-negative bacteria (broad-spectrum). An amide-based mutual prodrug (NA-SN) was been prepared following a single-step synthesis by condensing sulfanilamide with nalidixic acid. The compound (NA-SN) was evaluated for in-vitro antibacterial activity against some selected bacteria with significant results. Hydrolysis kinetics of the mutual prodrug were also studied in acidic and basic buffers. The present study reveals the pharmaceutical potential of mutual prodrugs.

Synthesis, Kinetics and Pharmacological Comparison of a Mutual Prodrug of Mefenamic Acid to Related Physical Mixture

A gastrosparing NSAID devoid of ulcerogenic side effects has been designed, synthesized and evaluated. This novel mutual prodrug consists of mefenamic acid and salicylamide. The structure was confirmed by IR, 1H NMR, and mass spectroscopy. The kinetics of ester hydrolysis was studied at pH 2 and 7.4 and in human plasma by HPLC. The pharmacological activities (anti-inflammatory, analgesic and ulcerogenic) were evaluated and compared with data for the related physical mixture (mefenamic acid and salicylamide). Then, oxidative stress parameters (LPO, GSH, CAT and SOD) were also measured and the results were compared with those for the physical mixture. The obtained results indicate that the synthesized ester is chemically stable, biolabile, and possesses optimum lipophilicity.