Enhancing oral bioavailability of Ca-DTPA by self double emulsifying drug delivery system (SDEDDS).

OBJECTIVE: BCS class III drug (highly soluble, poorly permeable) possesses low oral bioavailability. The research work highlights the utility of self-double emulsifying drug delivery system (SDEDDS) which are stable isotropic mixture of w/o primary emulsion and hydrophilic surfactants for improving oral bioavailability of Ca-DTPA (Calcium diethylenetriamine pentaacetate). Upon oral administration, SDEDDS rapidly emulsifies into w/o/w double emulsions in the aqueous gastrointestinal environment, with hydrophilic drugs entrapped inside oil reservoirs. METHODS: SDEDDS formulation was successfully developed using excipients, that is, medium chain triglycerides, oleic acid, phospholipids, Span 80, Tween 80 using double emulsification technique. RESULTS: The optimized formulation F4 (Aq. phase: 11.6%w,w; MCT & oleic acid: 70.9%w/w; Span 80:17.5%w/w; Lecithin:16%w/w and Tween 80 (10%w/w)) appeared bright yellow liquid which upon dilution appeared milky white within 2 min, droplet size (501.7 nm), pdi value (0.044), zeta potential (-52 mV), entrapment efficiency (79.6 ± 1.63), viscosity (72.2 ± 1.8 mpA.s), significant high cumulative in vitro drug permeation (CDP) and 2.17-fold increase in apparent permeability coefficient. Pharmacokinetic studies in rats showed 1.17-fold increases in AUC of F4 and comparatively higher plasma levels (Cmax) compared with pure drug administered orally. The Absolute (OF4, OD) and Relative bioavailability was found to be 14.52%, 12.35%, and 117.47%, respectively. CONCLUSION: The present studies have clearly demonstrated that SDEDDS could readily form w/o/w double emulsions in vivo with enhanced in vitro and in vivo oral bioavailability. Therefore, considerable augmentation in the rate and extent of oral drug absorption ratified the better performance of the SDEDDS in enhancing the bioavailability of Ca-DTPA.

Challenges in development and management of orphan drugs-a case study of Prussian blue insoluble.

Prussian blue insoluble (PB) is an antidote for decorporation of radioactive and non-radioactive isotopes of thallium and cesium. Its dosage in the form of capsules, Radiogardase-Cs, is a United States Food and Drug Administration approved formulation since 2003. In India and many other countries, this drug is not available and in case of requirement it is imported from US or Europe. The author has worked extensively to make PB capsules available in India. The drug was recently approved by the Indian drug regulatory agency, Central Drugs Standard Control Organisation and is now available commercially in India. However this drug needs special attention as it is an orphan drug with limited requirement. The post-approval phase of this drug poses a different set of challenges and the author has highlighted some key issues with probable approaches for post-approval product management.

In vitro and in vivo removal efficacy of insoluble Prussian blue in combination with calcium polystyrene sulfonate for thallium.

The similarities between thallium and potassium have suggested the use of calcium polystyrene sulfonate (CPS), an oral ion exchange resin, as a potential agent against thallium intoxication. Therefore, the study was an attempt to evaluate the efficacy of CPS and Prussian blue when given alone or in combination against thallium toxicity. The effect on binding capacity was investigated in terms of contact time, amount of CPS, influence of pH, simulated physiological solutions and interference of potassium ions. Also, rats were given single dose of thallium chloride (20 mg kg-1) and the treatment with PB and CPS was given for 28 days as CPS 30 g kg-1, orally, twice a day, PB 3 g kg-1, orally, twice a day and their combination. The effect of antidotal treatment was evaluated by calculating the thallium levels in various organs, blood, urine and feces. The results of the in vitro study indicated exceedingly quick binding in the combination of CPS and PB as compared to PB alone. Also, it was found that the binding capacity at pH 2.0 was considerably increased for PB with CPS (184.656 mg g-1) as compared to PB (37.771 mg g-1). Furthermore, statistically significant results were obtained in the in vivo study as after 7th day, thallium levels in blood of rats treated with combination were reduced by 64% as compared to control group and 52% as compared to alone PB treated group. Also, Tl retention in liver, kidney, stomach, colon and small intestine of combination treated rats was significantly reduced to 46%, 28%, 41%, 32% and 33% respectively, as compared to alone PB treated group. These findings demonstrate this as a good antidotal option against thallium intoxication.

Oral formulation of Prussian blue with improved efficacy for prophylactic use against thallium.

OBJECTIVE: The present study is aimed to enhance the efficacy of Insoluble Prussian blue (PB) in the stomach. PB formulation was developed comprising of PB in combination with pH modifying agents particularly magnesium hydroxide, calcium carbonate, sodium carbonate, and sodium bicarbonate. pH profile and the binding efficacy of the final formulation was evaluated in simulated gastric fluid (SGF). METHODS: The capsule formulation was optimized with desired in vitro characteristics. The final formulations (FF1-FF4) were evaluated for drug release, pH profile, and binding efficacy for thallium (Tl). The stability studies were performed in terms of drug assay, Fourier-transformed infrared (FTIR) spectroscopy and Thermo-gravimetric analysis (TGA). The in vivo study was performed in rats to determine the removal efficacy of optimized formulation (FF4) for Tl. RESULTS: The PB formulation consisting of optimized PB granules and pH modifying agents showed a significant increase in the binding efficacy for Tl in SGF at an equilibrium time of 24 h. The Maximum Binding Capacity (MBC) of FF1-FF4 was found to be higher than commercially available Radiogardase®-Cs capsules and PB granules alone in SGF. The blood Tl level in rats treated with FF4 showed three-fold decreases in the level of Tl in the blood (Cmax) and Area under Curve (AUC) as compared to the control. CONCLUSION: The results revealed that the developed oral PB formulation has a significantly higher efficiency of binding Tl at the acidic pH of the stomach thereby reducing its absorption into the systemic circulation. Thus, the optimized formulation of PB with pH-modifying agents is a better drug for prophylactic use in thallium ingestion.

Fabrication, characterization and efficacy evaluation of natural gum-based bioactive haemostatic gauzes with antibacterial properties.

Management of uncontrolled bleeding due to traumatic injuries occurring in battlefields and road traffic accidents is a major healthcare concern, especially in developing countries like India. Since natural coagulation mechanism alone is insufficient to achieve haemostasis quickly in such cases, application of an external haemostatic product is generally required to accelerate the coagulation process. We had recently reported preliminary comparison of four natural absorbent gums, which indicated towards haemostatic potential of gum tragacanth (GT) and xanthan gum (XG). Present study involves fabrication of haemostatic dressings incorporated with different concentrations of GT or XG, along with ciprofloxacin (a broad-spectrum antibiotic) and other excipients over woven cotton gauze. Prepared gauzes were investigated for physico-chemical characteristics, in-vitro blood interaction studies, antibacterial effect and in-vivo haemostatic efficacy in Sprague Dawley rats using two bleeding models. Acute dermal toxicity studies were also carried out as per OECD guidelines. SEM studies showed that gauzes coated with XG had thin, uniform layer of coating, while in case of GT; coating was comparatively rough with insoluble particles of GT adhering over gauze surface, forming voids on the fibers. Coated gauzes exhibited optimum mechanical properties in terms of tensile strength and percent extension at break. GT coated dressings showed good fluid uptake and retention ability in-vitro. Test gauzes were non-hemolytic in nature, did not elicit any dermal toxicity on animals' skin and had the ability to protect against E. coli infection. In-vivo efficacy studies in rat femoral artery and liver laceration bleeding models indicated that gauzes coated with 4% GT were able to clot blood in least time (36.67 ± 3.33s and 40 ± 2.58s respectively) as compared to other gum combinations and commercially available dressing 'Surgispon® (103.3 ± 4.22s and 85 ± 5.62s respectively). Results of this study validate our initial findings of the potential of gum tragacanth to be developed into a suitable haemostatic product.

Quantitative evaluation of mercury adsorption and removal efficacy of Spirulina (Arthrospira platensis) powder in mice.

Spirulina is a blue-green alga, grown in alkaline water and used for detoxification of several toxic metal ions. Apart from its nutritional value, it is also used for the decontamination of toxic metal ions. Therefore, present study was envisaged to evaluate the adsorption and removal efficiency of Spirulina powder for mercury. The adsorption efficiency of Spirulina was evaluated in terms of weight of adsorbent, contact time, simulated gastric (SGF) and intestinal (SIF) fluid, and mercury concentration. In vivo removal efficacy of Spirulina for mercury was evaluated in mice. The mercury content in major tissues, urine and feces was estimated. The whole tissue retention and excretion of mercury after treatment with Spirulina were taken as a measure of its metal ions removal efficacy. Activated charcoal was taken as a standard adsorbent for comparative study. The maximum adsorption capacity of Spirulina and charcoal for mercury was found to be 66.667 and 158.730 mg g-1 in water, 83.33 and 94.340 mg g-1 in SGF and 125.0 and 133.33 mg g-1 in SIF, respectively. In mice, Spirulina and activated charcoal were significantly reduced the mercury deposition in tissues and facilitated their excretion through feces. Spirulina has shown good adsorption and removal efficacy like activated charcoal. Therefore, Spirulina can be used as a potential adsorbent to remove mercury from the body.

Cellular and physiological approaches to evaluate the chelating effect of Chlorella on metal ion stressed lymphocytes.

Chlorella is a green alga consumed as dietary food supplement in pulverized form. In addition to its high nutritional value, it is reported as an excellent detoxifying agent. The pulverized Chlorella is partially soluble in water and insoluble portion has been reported for removal of mercury, cadmium and radioactive strontium from body. Chlorella contains a variety of metal-binding functional groups such as carboxyl, amino, phosphoryl, hydroxyl and carbonyl groups, which has high affinity towards various metal ions. The present study was envisaged to evaluate the chelating effect of water soluble fraction of Chlorella powder (AqCH) on metal ions. Fura-2 fluorescence ratio (F340/F380) was measured by fluorescence spectrometer (FS) after the exposure of chloride salt of metals viz., strontium, cobalt, barium, cesium, thallium and mercury to lymphocytes. Pretreatment of AqCH (0.1-20 mg mL-1) was given to evaluate the attenuating effect on fura-2 fluorescence ratio induced by metal ions. The intracellular levels of these metal ions were analyzed by atomic absorption spectrophotometer (AAS) and fluorescence microscopy (FM). Pretreatment with AqCH significantly attenuated the metal induced fluorescence ratio in dose-dependent manner. The results of AAS and FM were found in coherence with fura-2 fluorescence ratio which emphasized that AqCH significantly prevented the metal ions internalization. The present study suggests AqCH chelates with these metal ions and prevents its interaction with cells thereby reducing the intracellular mobilization of Ca2+.

pH-dependent Release Matrix Oral Formulation of Prussian Blue to Improve its Efficacy as an Internal Decorporation Agent.

BACKGROUND: Prussian Blue (PB) is available as conventional release dosage form "Radiogardase" with effective daily dose of 3-10 g (very high). The target site is the duodenum, where it inhibits the enterohepatic circulation of Cs & Tl ions, enhancing their fecal excretion. OBJECTIVE: To enhance efficacy, target release, reduce the dose and side effects, oral pH-dependent matrix formulation of PB based on in-situ gelation of sodium alginate along with calcium salts was formulated and evaluated. METHODS: Different combinations of matrix granules were formulated and optimized. The optimized one was compressed using Polyvinylpyrrolidone K30 (Pvp K30) in different batches and optimized. Langmuir adsorption isotherm was used to assess in-vitro binding efficacy of formulation to thallium using atomic absorption spectroscopy. The proof of concept i.e., drug release in the duodenum was studied through pharmacoscintigraphy using radiolabeled formulation in rabbits. RESULTS: The optimized granules showed no drug release in an acidic medium for 2 h whereas complete empty of the basket in a basic medium within 30-60 minutes. The matrix tablet formulation with Pvp K30 (10% w/w) was optimized with desired hardness and optimum in-vitro release profile. The release data fitted to various linear kinetic models, Hixson-Crowell r2 (0.9906) best fit, confirmed the erosion-based release mechanism. The maximum binding capacity (MBC) was found significantly higher (89.60 mg Tl/g formulation) than that of PB API (65.90 mg Tl /g PB API). Pharmacoscintigraphic images confirmed intact formulation in the stomach up to 2h and burst release in intestine thereafter. CONCLUSION: The results exemplify oral pH-dependent PB matrix formulation which achieved desirable target release at the duodenum and in-vitro binding efficacy towards Tl ion was appreciable.

Hyaluronate-functionalized hydroxyapatite nanoparticles laden with methotrexate and teriflunomide for the treatment of rheumatoid arthritis.

Rheumatoid arthritis (RA), an autoimmune inflammatory disorder is currently incurable. Methotrexate and Teriflunomide are routinely prescribed drugs but their uses are limited due to severe hepatotoxicity. Hyaluronic acid (HYA) is a targeting ligand for CD44 receptors overexpressed on inflamed macrophages. The present investigation aimed at design and fabrication of HYA coated hydroxyapatite nanoparticles (HA-NPs) loaded with Methotrexate (MTX) and Teriflunomide (TEF) (HAMT-NPs) to form HYA-HAMT-NPs for the treatment of RA. HYA-HAMT-NPs showed the nanoscale size of 274.9 ± 64 nm along with a zeta potential value of -26.80 ± 6.08 mV. FTIR spectra of HYA and HYA-HAMT-NPs proved the coating of HYA on HYA-HAMT-NPs. HYA-HAMT-NPs showed less cell viability compared to drugs on RAW 264.7 macrophage cells. A biodistribution study by gamma scintigraphy imaging further strengthened the results by revealing significantly higher (p<0.05) percentage radioactivity (76.76%) of HYA-HAMT-NPs in the synovial region. The results obtained by pharmacodynamic studies ensured the better efficacy of HYA-HAMT-NPs in preventing disease progression and promoting articular regeneration. Under hepatotoxicity evaluation, liver histopathology and liver enzyme assay revealed ~29% hepatotoxicity was reduced by HYA-HAMT-NPs when compared to conventional FOLITRAX-10 and AUBAGIO oral treatments. Overall, the results suggest that HYA-HAMT-NP is a promising delivery system to avoid drug-induced hepatotoxicity in RA.

Facile functionalization of Teriflunomide-loaded nanoliposomes with Chondroitin sulphate for the treatment of Rheumatoid arthritis.

This research aims to coat Teriflunomide (TEF) loaded conventional nanoliposomes (CON-TEF-LIPO) with Chondroitin sulphate (CS) to produce CS-TEF-LIPO for the effective treatment of Rheumatoid arthritis (RA). Both CON-TEF-LIPO and CS-TEF-LIPO were produced, characterized and evaluated for their active targeting potential towards CD44 receptors. Cell cytotoxicity, cell viability and intracellular uptake study on differentiated U937 and MG-63 cells demonstrated the active targeting of CS-TEF-LIPO towards CD44 receptors. Furthermore, in vivo pharmacodynamic, biochemical, radiological and histopathological studies performed in adjuvant induced arthritic (AIA) rat model showed a significant (P < 0.05) reduction in inflammation in arthritic rat paw in CS-TEF-LIPO group compared to TEF and CON-TEF-LIPO groups. Moreover, liver toxicity study revealed that CS-TEF-LIPO showed no signs of toxicity and biodistribution study revealed the accumulation of CS-TEF-LIPO in synovial region of arthritic rat. Taken together, results suggest that CS-TEF-LIPO could provide a new insight for an effective treatment of RA.

Preparation, Characterization, and In Vivo Pharmacoscintigraphy Evaluation of an Intestinal Release Delivery System of Prussian Blue for Decorporation of Cesium and Thallium.

BACKGROUND: Prussian blue (PB, ferric hexacyanoferrate) is approved by US-FDA for internal decorporation of Cesium-137 (137Cs) and Thallium-201 (201Tl). AIM: Since PB is a costly drug, pH-dependent oral delivery system of PB was developed using calcium alginate matrix system. METHODS: Alginate (Alg) beads containing PB were optimized by gelation of sodium alginate with calcium ions and effect of varying polymer concentration on encapsulation efficiency and release profile was investigated. Scanning electron microscopy (SEM) was carried out to study surface morphology. Adsorption efficacy of Alg-PB beads for 201Tl was evaluated and compared with native PB. In vivo pH-dependent release of the formulation was studied in humans using gamma scintigraphy. RESULTS: Encapsulation efficiencies of Alg-PB beads with 0.5, 1.0, 1.5, and 2.0% polymer solution were 99.9, 91, 92, and 93%, respectively. SEM and particle size analysis revealed differences between formulations in their appearance and size distribution. No drug release was seen in acidic media (pH of 1-2) while complete release was observed at pH of 6.8. Dissolution data was fitted to various mathematical models and beads were found to follow Hixson-Crowell mechanism of release. The pH-dependent release of beads was confirmed in vivo by pharmacoscintigraphy in humans.