Manish Nivsarkar

A novel model for NSAID induced gastroenteropathy in rats.

INTRODUCTIONnProgress in management of Nonsteroidal anti-inflammatory drug (NSAID) induced gastrointestinal toxicity requires the availability of appropriate experimental animal models that are as close to humans as feasible. Our objective was to develop a rat model for NSAID-induced gastroenteropathy and also to simulate the common clinical scenario of co-administration of NSAID and proton pump inhibitor (PPI) to explore if PPI contribute to exacerbation of NSAID-enteropathy.nnnMETHODSnRats were treated twice daily with pantoprazole sodium (PTZ; 10mg/kg peroral) or vehicle for a total of 10days. In some experiments, Diclofenac sodium (DCF; 9mg/kg) or vehicle was administered orally twice daily for the final 5days of PTZ/vehicle administration. After the last dose on 9th day, rats in all the groups were fasted but water was provided ad libitum. 12h after the last dose on 10th day, rats in all the groups were euthanized and their gastrointestinal tracts were assessed for haemorrhagic lesions, lipid peroxidation, intestinal permeability and gastrointestinal luminal pH alterations. Changes in haemoglobin, haematocrit and serum levels of albumin, total protein, ALT and bilirubin were calculated.nnnRESULTSnThe macroscopic and histological evidence suggested that administration of DCF resulted in significant gastroenteropathic damage and co-administration of PTZ resulted in significant exacerbation of NSAID enteropathy, while attenuation of NSAID induced gastropathy was observed. Our results were further supported by the significant decrease in haemoglobin and haematocrit levels and serum levels of albumin and total proteins, an increase in oxidative stress and intestinal permeability with the use of DCF either alone or in combination with PTZ.nnnCONCLUSIONSnThis model was developed to simulate the human clinical situation during NSAID therapy and indeed the present DCF regimen caused both gastric and small bowel alterations, such as multiple erosive lesions, together with a decrease in haemoglobin, haematocrit, serum albumin, serum total protein levels and IP alteration, known to occur in patients receiving NSAIDs. Additionally, this paper provides yet another evidence for PPI induced exacerbation of NSAID enteropathy.

Clinical importance of nonsteroidal anti-inflammatory drug enteropathy: the relevance of tumor necrosis factor as a promising target

The pathogenesis of nonsteroidal anti-inflammatory drug (NSAID) enteropathy is still unclear, and consequently, there is no approved therapeutic strategy for ameliorating such damage. On the other hand, molecular treatment strategies targeting tumor necrosis factor (TNF) exerts beneficial effects on NSAID-induced intestinal lesions in rodents and rheumatoid arthritis patients. Thus, TNF appears to be a potential therapeutic target for both the prevention and treatment of NSAID enteropathy. However, the causative relationship between TNF and NSAID enteropathy is largely unknown. Currently approved anti-TNF agents are highly expensive and exhibit numerous side effects. Hence, in this review, the pivotal role of TNF in NSAID enteropathy has been summarized and plant-derived polyphenols have been suggested as useful alternative anti-TNF agents because of their ability to suppress TNF activated inflammatory pathways both inxa0vitro and inxa0vivo.

Equilibrium between anti-oxidants and reactive oxygen species: a requisite for oocyte development and maturation

Reactive oxygen species (ROS) are required for cellular functioning and are controlled by anti‐oxidants. The ROS influence the follicles, oocytes, endometrium, and their environment. The luteinizing hormone surge initiates a massive recruitment of ROS that modulates major reproductive functions namely, oocyte maturation, ovarian steroidogenesis, corpus luteal function, and luteolysis. The anti‐oxidant system balances ROS generation and maintains the cellular functions. Both enzymatic and non‐enzymatic anti‐oxidants namely, vitamins and minerals are present in the follicles and protect the oocytes from the damaging effects of ROS. The overproduction of ROS leads to oxidative stress that affects the quality of oocytes and subsequent anovulation. Although researchers have tried to establish the role of ROS and anti‐oxidants in oocyte development, still this aspect needs to be revisited. This review discusses the importance of the ROS and anti‐oxidant balance that is required for the development and maturation of oocytes. There are increasing data on the activity of ROS and anti‐oxidants in supporting oocyte development and maturation. However, extensive research is required to identify the safe physiological concentration and duration of both the ROS and anti‐oxidants that are required to facilitate oocyte development and maturation during in vitro and in vivo conditions.

Co-administration of quercetin with pantoprazole sodium prevents NSAID-induced severe gastroenteropathic damage efficiently: Evidence from a preclinical study in rats

Management of Nonsteroidal anti-inflammatory drug (NSAID)-induced gastroenteropathy has emerged as a major medical and socioeconomic problem mainly because the highly efficacious gastroprotective drugs i.e. proton pump inhibitors (PPIs) like pantoprazole sodium (PTZ), worsen the NSAID-induced enteropathic damage and lack of approved therapeutic strategies/interventions to prevent this damage. Hence, the primary objective of the current study was to assess whether we can protect the GI mucosa against gastroenteropathic damage caused by diclofenac sodium (DIC) in rats by co-administration of PTZ and quercetin (QCT). Rats were treated twice daily with QCT (35, 50 and 100mgkg-1 peroral) and/or PTZ (4mgkg-1) or vehicle for a total of 10 days. In some experiments, DIC (9mgkg-1) was administered orally twice daily for the final 5days of PTZ/QCT+PTZ/vehicle administration. Rats in all the groups were fasted after the last dose on 9th day, but, water was provided ad libitum. 12h after the last dose on 10th day, rats were euthanized and their GI tracts were assessed for haemorrhagic damage, lipid peroxidation, intestinal permeability and GI luminal pH alterations along with haematological and biochemical estimations. The experimental evidences suggested that co-administration of QCT with PTZ significantly attenuated the exacerbation of NSAID-induced enteropathic damage in a dose dependent manner. The combination of PTZ 4mgkg-1 and QCT at the doses of 50 or 100mgkg-1 was found to effective in preventing the DIC-induced gastroenteropathy. The present report focuses on the gastroenteroprotective ability of QCT and the mechanisms may be related to its ability to prevent GI blood loss, the lipid peroxidation, intestinal permeability alteration and alteration in GI luminal pH.

Formulation and optimization of doxorubicin loaded polymeric nanoparticles using Box-Behnken design: ex-vivo stability and in-vitro activity

&NA; Biodegradable nanoparticles (NPs) have gained tremendous interest for targeting chemotherapeutic drugs to the tumor environment. Inspite of several advances sufficient encapsulation along with the controlled release and desired size range have remained as considerable challenges. Hence, the present study examines the formulation optimization of doxorubicin loaded PLGA NPs (DOX‐PLGA‐NPs), prepared by single emulsion method for cancer targeting. Critical process parameters (CPP) were selected by initial screening. Later, Box‐Behnken design (BBD) was used for analyzing the effect of the selected CPP on critical quality attributes (CQA) and to generate a design space. The optimized formulation was stabilized by lyophilization and was used for in‐vitro drug release and in‐vitro activity on A549 cell line. Moreover, colloidal stability of the NPs in the biological milieu was assessed. Amount of PLGA and PVA, oil:water ratio and sonication time were the selected independent factors for BBD. The statistical data showed that a quadratic model was fitted to the data obtained. Additionally, the lack of fit values for the models was not significant. The delivery system showed sustained release behavior over a period of 120 h and was governed by Fickian diffusion. The multipoint analysis at 24, 48 and 72 h showed gradual reduction in IC50 value of DOX‐PLGA‐NPs (p < 0.05, Fig. 9). DOX‐PLGA‐NPs were found to be stable in the biological fluids indicating their in‐vivo applicability. In conclusion, optimization of the DOX‐PLGA‐NPs by BBD yielded in a promising drug carrier for doxorubicin that could provide a novel treatment modality for cancer. Graphical abstract Figure. No caption available.

Overcoming the exacerbating effects of ranitidine on NSAID-induced small intestinal toxicity with quercetin: Providing a complete GI solution

There is a need to find/discover novel leads to treat complex and/or multi-factorial-pathogenic disease(s) like Nonsteroidal anti-inflammatory drugs (NSAID)-induced gastroenteropathy or gastrointestinal (GI) toxicity as it has emerged as an important medical and socioeconomic problem. There is no approved therapeutic strategy to prevent NSAID-induced enteropathic damage and highly effective gastro-protective drugs such as ranitidine hydrochloride (RAN) exacerbate it. In this purview, the multi target drug discovery approach (MTDD), combination approach and hit to lead strategies based on the foundation of ethnopharmacology and/or reverse pharmacology holds strong potential. Hence, the primary objectives of the current study were to explore the mechanism behind the preventative/curative effects of quercetin (QCT) on RAN exacerbated diclofenac sodium (DIC)-induced enteropathic damage and to assess the effects of co-administration of QCT and RAN on DIC-induced gastropathic damage in rats. Rats were treated twice daily with QCT (35, 50 and 100xa0mgxa0kg-1 PO) and/or RAN (15xa0mgxa0kg-1 PO) or vehicle for a total of 10 days. In some experiments, DIC (9xa0mgxa0kg-1) was administered orally twice daily for the final 5 days of RAN/QCTxa0+xa0RAN/vehicle administration. Rats in all the groups were fasted after the last dose on 9th day (free access to water). 12 h after the last dose on 10th day, rats were euthanized and their GI tracts were assessed for haemorrhagic damage, alteration in xanthine oxidase (XO) activity, lipid peroxidation, intestinal permeability and GI luminal pH alterations along with haematological and biochemical estimations. The macroscopic, haematological, biochemical and histological evidences suggested that, though, RAN prevented the DIC-induced gastric injury, it exacerbated enteropathic damage. However, QCT not only significantly attenuated the RAN-induced exacerbation of enteropathic damage caused by DIC at the doses of 50 and 100xa0mgxa0kg-1, but, this combination provided complete GI safety against the toxic effects of DIC too. The mechanisms behind the gastro-enteroprotective ability of QCT may be related to its ability to inhibit XO activity thus, preventing enhanced oxidative stress on GI tissues, prevent lipid peroxidation, IP alteration and alteration in GI luminal pH. The preventative effects of QCT on NSAID-induced gastroenteropathy were ably supported by the QCT induced prevention of GI blood loss and serum protein loss. These pharmaco-mechanistic results of QCT are aligning to combination based MTDD approach and hence we propose it as a promising lead to treat NSAID-gastroenteropahty and related complications.

In vitro - In vivo metabolism and pharmacokinetics of picroside I and II using LC-ESI-MS method.

Picroside I and II, iridoid glycosides, are the major active markers of roots and rhizomes of Picrorhiza kurroa (family: Scrophulariaceae). The rhizomes of P.xa0kurroa have been traditionally used to treat worms, constipation, low fever, scorpion sting, asthma and ailments affecting the liver. Various Ayurvedic and herbal preparations are available in the market which contains P.xa0kurroa e.g. Arogyavadhini vati, Tiktadi kwath, Picrolax capsules and suspension. These preparations are used without any significant pharmacokinetics data. Previously, we have reported that oral bioavailability of picroside I and II is low. Most of the iridoid glycosides are primarily metabolized by intestinal microbial flora. So, it is necessary to determine the metabolic profile of picroside I and II and check the correlation with lower bioavailability. Therefore, this study was designed to check metabolic (inxa0vitro and inxa0vivo) profile along with pharmacokinetic profile of picroside I and II. For this, a sensitive and selective LC-ESI-MS method was developed and validated for simultaneous determination of picroside I and II in rat plasma. Chromatographic separations were performed on C18 column. The mobile phase consisted of acetonitrile: 10xa0mM ammonium acetate buffer [90:10 v/v], pH 3.5. In-vitro Metabolic study was performed on rat liver microsomes and primary hepatocytes. In-vivo pharmacokinetic and metabolic profile of picroside I and II was generated after oral administration of Kutkin (mixture of picroside I and II) to Sprague-Dawley rats. Various pharmacokinetic parameters viz. Cmax, Tmax, AUC(0-t) were determined. In metabolic study, eight metabolites of picroside I and six metabolites of picroside II were identified inxa0vitro, out of which four metabolites for each picroside I and picroside II were identified inxa0vivo.

Curcumin, a component of turmeric, efficiently prevents diclofenac sodium-induced gastroenteropathic damage in rats: A step towards translational medicine

There is a need to find/discover novel leads to treat complex and/or multi-factorial disease(s). Curcumin (CUR) is one of the promising lead molecules which need its further evaluation against NSAID-induced gastroenteropathy. Hence, the aim of the present study was to explore the pharmaco-mechanistic efficacy of CUR against NSAID-induced gastroenteropathy. Rats were treated twice daily with CUR (25, 50 and 100xa0mgxa0kg-1 peroral) or vehicle for 10 days. In some experiments, diclofenac sodium (DIC; 9xa0mgxa0kg-1) was administered orally twice daily for the final 5 days of CUR/vehicle administration. After the last dose on 9th day, rats were fasted. 12 h after the last dose on 10th day, rats were euthanized and their GI tracts were assessed for haemorrhagic lesions, lipid peroxidation, intestinal permeability and GI luminal pH alterations along with haemato-biochemical estimations. The macroscopic, biochemical, haematological and histological evidences suggested that co-administration of CUR resulted in dose dependent attenuation of the NSAID-induced gastroenteropathic damage and the mechanisms may be related to its ability to prevent the NSAID-induced alterations in the GI luminal pH, lipid peroxidation/oxidative stress, GI blood loss and intestinal permeability alteration. Based on these pharmaco-mechanistic results we propose it as a promising lead to treat NSAID-gastroenteropahty.

Development and Optimization of an Ex Vivo Colloidal Stability Model for Nanoformulations

Nanotechnology is having a significant impact in the drug delivery systems and diagnostic devices. As most of the nanosystems are intended to be administered in vivo, there is a need for stability models, which could simulate the biological environment. Instability issues could lead to particle aggregation and in turn could affect the release of the drug from the nanosystems and even lead to clogging of the systemic blood circulation leading to life-threatening situation. We have developed an ex vivo colloidal stability model for testing the stability of nanosystems over a period of 48xa0h, which is the typical residence time of the nanoparticles in vivo. Tissue homogenates of rat spleen, brain, kidney, and liver were stabilized and optimized for the study; additionally, plasma and serum were used for the same. Poly (lactide-co-glycolic acid) nanoparticles were used as model nanosystem, and no significant change was found in the size and polydispersity index of the nanoparticles in the biological solutions. Moreover, no change in morphology was observed after 48xa0h as observed by TEM microscopy. Hence, the developed model could prevent the failure of the developed nanosystem during clinical and preclinical application by serving as an initial checkpoint to study their interaction with the complex milieu.

D-limonene possesses cytotoxicity to tumor cells but not to hepatocytes

Resu l t s and d i scuss ion: In vitro dose dependent and time dependent studies of D-limonene shows significant reduction in viability of K562 cells. Dose dependent studies of doxorubicin and D-limonene treatment for 48 h shows significant reduction in viability of primary hepatocytes with doxorubicin whereas, the reduction was non significant with D-limonene. D-limonene treatment for 14 days also shows dose dependent reduction in tumor volume in K562 tumor xenograft C57BL/6 mice.