Thermoresponsive gel containing bilirubin nanoparticles exerts anti-inflammatory effects by inhibiting neutrophil infiltration and augmenting interleukin-10 levels in carrageenan-induced rat paw edema.

BACKGROUND: Topical corticosteroids treat cutaneous inflammation but have side effects. In earlier studies, bilirubin exhibited anti-inflammatory effect, but its hydrophobicity and poor absorption limit its potential. AIM: Synthesis of bilirubin nanoparticles (BNP) and bilirubin nanoparticles gels (BNP gel) to study the anti-inflammatory effect of topical BNP gel against carrageenan-induced rat paw edema in Wistar rats. MATERIALS AND METHODS: BNP were synthesized, and BNP gels were prepared by mixing BNP of different concentrations with pluronic F-127 (PF-127). A different group for each formulation was assigned with five rats in each group. After 1 h of carrageenan (1% [w/v]) injection in each group, different gels were applied topically to their respective groups. Paw edema size, percent inflammation, percent edema inhibition, and inhibition time50 were evaluated. Interleukin-10 (IL-10) levels and neutrophil infiltration in rat paw tissue were evaluated by enzyme-linked immunosorbent assay and hematoxylin and eosin, respectively. RESULTS: Synthesized spherical-shaped BNP had negative zeta potential. BNP gels markedly reduced paw edema size and % inflammation as compared to carrageenan and bulk bilirubin gel (Bulk B gel) treated group and significantly increased IL-10 levels and inhibited neutrophil infiltration. CONCLUSION: BNP gels exhibited a better anti-inflammatory effect than bulk B gel and comparable anti-inflammatory potential with clobetasol.

Nanocellulose-gellan cross-linked scaffolds for vaginal delivery of fluconazole.

The objective of this research is to formulate lyophilized fluconazole-loaded nanocellulose-gellan scaffolds cross-linked using trisodium trimetaphosphate as a vaginal drug delivery system. The effect of polymers (nanocellulose and gellan gum) and cross-linking agents on drug release and mucoadhesive strength were determined by approaching a two-factor three-level central composite experimental design. The optimal formulation of the fluconazole-loaded cross-linked rice or wheat nanocellulose-gellan based scaffolds comprised of the concentration of polymers (4.91 % w/v or 4.99 % w/v) and trisodium trimetaphosphate (16.43 % w/v or 15.83 % w/v), respectively. The infrared spectra confirmed the cross-linking of nanocellulose and gellan gum while the thermal graph revealed the higher thermal stability of cross-linked scaffolds. The diffractogram of the scaffolds unveiled their amorphous nature while the electron micrographs depict the porous nature of the fluconazole-loaded nanocellulose-gellan scaffolds. The phosphorylated cross-linked nanocellulose-gellan scaffolds represent more swelling (8-fold higher), porosity (>83 %), tensile strength (>34 MPa), and mucoadhesive strength (>1940 mN), and less enzymatic degradation rate over the non cross-linked scaffolds. The optimal batch of cross-linked nanocellulose-gellan scaffolds provided a sustained release of 99 % of fluconazole over 24 h with 1.19-fold higher ex-vivo vaginal permeation over the native scaffolds. In addition, the phosphorylated nanocellulose-gellan based scaffolds exhibit improved antifungal activity and non-cytotoxicity.

Anti-Inflammatory Therapeutics: Conventional Concepts and Future with Nanotechnology.

Anti-inflammatory therapies currently in use mainly include steroidal and non-steroidal drugs. Contrary to their side effects, the steroid hormones glucocorticoids, which are synthetic versions of natural cortisol, are nevertheless often employed to treat a variety of inflammatory disorders. Other drug class of choice is non-steroidal drugs which mainly target COX-2 and hence the synthesis of prostaglandins, particularly PGE2. To cure both the short-term effects of chronic inflammatory disorders and the long-term symptoms of acute inflammation, pharmaceutical chemists are in continuous search for more potent and less toxic agents. Apart from these two drug classes, phytochemicals are gaining the attention of researchers as source of alternative antiinflammatory agents. However, every drug class has its own advantages or disadvantages thus requiring intervention of newer approaches. Currently, drugs used for anti-inflammatory therapies are costly with low efficacy, high health risk, and socio-economic impact due to the concern issue of their toxicity. Recently, nano-drug delivery system has been experiencing main interest as a new approach for targeting therapeutic agents to the target sites in a controlled, sustained manner and has various advantages as compared to the conventional drug delivery system like, increased solubility, bioavailability, improved pharmacokinetic profile of drugs, surface area and rate of dissolution and additionally, overcomes the problems related to hydrophobicity, toxicity. Present review summarized the intervention of nanotechnology to overcome the limitations/ risk associated with current anti-inflammatory drugs of different classes.

Novel preparation of bilirubin-encapsulated pluronic F-127 nanoparticles as a potential biomaterial for wound healing.

Cutaneous wounds deteriorate the health of patients and liable for high economic loss. Previous studies showed promising wound healing potentials of bilirubin, however, this macromolecule constrained with poor water solubility and skin penetration. In this study, Pluronic F-127, a non-ionic copolymer surfactant, was used for the encapsulation of the wound healing agent the bilirubin. With this strategy, spherical shaped bilirubin nanoparticles of ∼100-150 nm with zeta potential ranging from -13.43 ± 0.56 to -17.53 ± 0.43 mV were obtained. Topical applications of bilirubin nanoparticle (0.3%) on cutaneous wounds of rats showed promising wound healing in comparison with other topical treatments. This topical nano-formulation also modulates the cytokine and growth factor responses in the treated group. On day 7 of healing, bilirubin nanoparticles treatment significantly reduced TNF-α and increased IL-10 levels with increased VEGF and TGF-ß1 expressions. Simultaneously, prominent pro-healing activities could be observed histopathologically. These include increased blood vessels, reduced inflammatory cells, more myofibroblasts, increased deposition of collagen fibres, and early re-epithelialization. The changes were prominent in bilirubin nanoparticles (0.3%) treated group indicating better granulation tissue, quality of healing and wound maturity. In conclusion, the proposed new encapsulated bilirubin nanoparticles strategy significantly improved wound healing by modulation of cytokines and growth factors response in comparison with native bulk bilirubin. These observations support its potential as a novel biomaterial for wound healing in the future.

Nanomaterials of Natural Bioactive Compounds for Wound Healing: Novel Drug Delivery Approach.

Wound healing is a biological phenomenon of the body involving sequential biochemical processes that are primarily involved in restoring the cellular integrity of the organ. The market related to wound-care products has extensively been expanded and crossed over fifteen billion US dollars, along with twelve billion US dollars for treating wound scars. Different bioactive compounds have shown their various pharmacological actions including wound healing activity. Natural bioactive agents have gained much attention in wound management due to their beneficial nature of possessing least side effects. Some of the bioactive compounds which have shown pronounced wound healing potentials,such as curcumin, quercetin, lawsone, resveratrol, aloe vera, astragaloside, essential oils, growth factors, andrographolide, bilirubin, etc. Most of the natural bioactive agents have limited applicability in clinical practices due to poor aqueous solubility, fast degradation rate and low bioavailability. These problems have been overcome in last few years by encapsulating them into nano-formulations. The nanomaterials of bioactive agents offer discrete advantages like high surface area to volume ratio and nanoscale size offering alternations in physical and chemical properties. These nanomaterials also have sustained controlled release delivery, which seems to be very effective for the lengthy process of wound healing. Many investigations by the global researchers have focused on the emergence of nanomaterials in wound healing applications. In the present review, different natural bioactive agents in the form of nanoformulations have been discussed for wound healing potentials.

Carboxymethyl modification of Cassia obtusifolia galactomannan and its evaluation as sustained release carrier.

Carboxymethylation of Cassia obtusifolia galactomannan was carried out by Williamsons synthesis. Modification of galactomannan was confirmed by Fourier-transform infrared and 1H-Nuclear magnetic resonance spectroscopy. The degree of carboxymethyl substitution was found to be 1.69. Carboxymethylation was observed to increase the powder flow, solubility and swelling, while decrease the viscosity and alter the compression characteristics from elastic to plastic. The results of X-ray diffraction and scanning electron microscopy studies indicated increase in degree of crystallinity. The modified gum was used for preparing diclofenac sodium-loaded, Ca2+-gelled beads which were coated with gastroresistant Eudragit-L100. The formulation of beads was optimized using central composite experimental design. The optimal formulation of beads contained carboxymethylated Cassia galactomannan-2.85%,w/v and calcium chloride -15%,w/v, which showed yield -185.4%, entrapment-95.41% and release of 93.32% of diclofenac over 24 h. The release of diclofenac followed first-order kinetics by Super case-II transport. Thus, carboxymethyl Cassia galactomannan appears suitable for sustained drug delivery.

Silica coating of carboxymethyl tamarind kernel polysaccharide beads to modify the release characteristics.

In present study, the release characteristics of ibuprofen-loaded carboxymethyl tamarind kernel polysaccharide beads were modified by coating with silica. The influence of concentrations of carboxymethyl tamarind kernel polysaccharide, calcium chloride and tetraethoxysilane on the % entrapment and in vitro release of ibuprofen was optimized using response surface methodology. The coating of beads with silica restricted the drug release from the beads but at the same time the ethanol formed as by-product of the sol gel process leached out the drug. The optimized batch of beads were prepared using carboxymethyl tamarind kernel powder-12.5 (%, w/v), calcium chloride-10.12 (%, w/v) and coated with tetraethoxysilane-0.25 M, entrapped 89.2% and released 92% of drug over 24 h. Energy dispersive X-ray analysis confirmed the coating of silica on the beads. The coating with silica shielded the crevices on the surface of beads but it did not elicit any significant change in thermal stability of beads. Further, in vitro release was found to be in good agreement with the swelling study. Modeling analysis revealed that ibuprofen was released from the beads following zero-order kinetics with erosion of the matrix as the main mechanism of drug release. Thus, silica coating provides a facile strategy to formulate sustained release formulations.

Optimization of the Interaction between Diclofenac and Ibuprofen with Benzalkonium Chloride to Prepare Ocular Nanosuspension.

BACKGROUND: Non-steroidal anti-inflammatory drugs are most commonly used in the management of ocular inflammations. These drugs have poorly aqueous solubility and weakly acidic nature. They interact with cationic quaternary ammonium compound benzalkonium chloride, used as a preservative in ophthalmic formulations, to form insoluble complexes. To overcome this incompatibility solubilizers like polysorbate 80, lysine salts, tocopheryl polyethylene glycol succinate etc. are used which are quite irritating and affect the corneal integrity. OBJECTIVE: The objective of the present study is to formulate nonirritating, compatible, microbiologically stable ophthalmic formulation with good corneal permeation characteristics. The interaction between diclofenac sodium or ibuprofen with benzalkonium chloride was optimized using a central composite experimental design to prepare nanosuspensions by nanoprecipitation. METHODS: The optimized batches of nanosuspensions were evaluated for ex vivo corneal permeation study, preservative challenge test and physical stability. The optimal concentrations of benzalkonium chloride for diclofenac sodium (0.1%, w/v) and ibuprofen (0.1% w/v) nanosuspensions were determined to be 0.002%(w/v), which had a respective average particle size of 440 nm and 331 nm, respectively. The nanosuspensions of diclofenac sodium and ibuprofen provided 1.6 and 2.1- fold higher ex vivo corneal permeation than their respective conventional aqueous solution dosage forms. Further, the concentration of benzalkonium chloride used in the formulations showed adequate preservative efficacy. RESULTS: The optimized nanosuspension formulations of diclofenac and ibuprofen were found to be physically stable and microbiologically safe with greater corneal penetration than the conventional solution dosage forms.

Improved antioxidant, antimicrobial and anticancer activity of naringenin on conjugation with pectin.

The purpose of the present study was to improve the aqueous solubility of naringenin by conjugating with water-soluble polysaccharide carrier, pectin. The pectin-naringenin conjugate was synthesized employing dicyclohexylcarbodiimide and dimethylaminopyridine. The conjugation was confirmed by various physicochemical characterizations. The results of differential scanning calorimetry, X-ray diffraction and morphological analyses revealed semi-crystalline nature of the conjugate. The chromatographic analysis showed 37.069 µg naringenin/mg of conjugate. The conjugate was determined to have molecular weight of 6.22 × 104 kDa by static light scattering. In silico molecular mechanistic simulations performed for pectin and naringenin revealed the energetic and geometrical stability within the polysaccharide-polyphenol conjugate. The critical aggregation concentration was in the range of 44.67-56.23 µg/mL as determined by dynamic light scattering and fluorescence spectroscopy. On in vitro release, 99.4% (pH 1.2) and 57.62% (pH 7.4) of naringenin were found to be released over a period of 30 h and 48 h, respectively. Further, the release of naringenin followed Higuchi's square-root kinetics with diffusion as the possible release mechanism. A comparative evaluation for antioxidant activity revealed a significantly higher radical scavenging activity of conjugate over the naringenin. Further, the conjugate exhibited significantly higher antimicrobial action against Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa while a comparable antimicrobial activity was observed against Escherichia coli and Bacillus subtilis. The cytotoxicity studies of the synthesized conjugate showed anti-cancer activity against NIH: OVCAR-5 cells. In conclusion, the pectin-naringenin conjugate presented hydrocolloidal properties with improved therapeutic efficacy and delivery over the native polyphenol.

Thiol modified Moringa gum - A potential bioadhesive polymer.

In the present study Moringa gum was modified by thiolation to enhance its mucoadhesive potential. Thiolation was accomplished by esterification with thioglycolic acid. Thiolated Moringa gum was characterized by FT-IR, TGA, DSC, XRD and SEM-EDX studies. Modified gum was found to have 0.956 ± 0.024 mM of thiol groups/g as determined by Ellman's method. The greater force of detachment of polymer compacts of modified gum from the mucin discs as compared to native gum indicates its enhanced mucoadhesive potential. The thiolated Moringa gum was formulated into buccal tablets using metronidazole benzoate as the test drug. A comparative evaluation of buccal tablets revealed 1.5-fold higher ex vivo bioadhesion time of buccal tablets of modified gum than the native gum. The results of in vitro release studies showed that modified gum tablets provided a sustained release of metronidazole over 24 h of the study following First-order kinetics with diffusion mechanism of release.

Moringa gum-g-poly(N-vinyl-2-pyrrolidone) - a potential buccoadhesive polymer.

In the present study, MG-g-poly(NVP) was synthesized using microwave-assisted graft co-polymerization reaction. Synthesis of graft co-polymer was optimized using response surface methodology. The influence of concentration of Moringa gum, N-vinyl-2-pyrrolidone and ammonium persulfate on grafting efficiency of graft copolymer was studied using 3-factor, 3-level central composite experimental design. The optimal calculated parameters were found to be concentration of Moringa gum-1% (w/v), N-vinyl-2-pyrrolidone-2% (w/v), and ammonium persulfate-10 mMol/L, which yielded a graft co-polymer of% grafting efficiency (24.23%). The graft co-polymer were further characterized by Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy studies. The results of characterization revealed that grafting of N-vinyl-2-pyrrolidone on Moringa gum decreases its crystallinity and makes its surface smoother. Graft copolymer was further evaluated for pharmaceutical application by formulating clotrimazole-loaded buccal discs. A comparative evaluation of buccal discs of graft co-polymer with native gum revealed higher ex-vivo bioadhesion time and greater sustained release effect of the graft copolymer than of native gum.

Polyelectrolyte complex of carboxymethyl gum katira-chitosan: Preparation and characterization.

In the present study polyelectrolyte complex between carboxymethyl gum katira and chitosan were prepared and evaluated for drug delivery using ofloxacin as model drug. The carboxymethyl gum katira-chitosan polyelectrolyte complex was characterized by FTIR, DSC, TGA, DTG, XRD and SEM. The influence of concentration of CMGK/CH and drug loading (%) on yield (%) and drug entrapment (%) was studied using response surface methodology. The result of the study revealed that increasing the relative proportion of CMGK/CH in carboxymethyl gum katira-chitosan polyelectrolyte complex decreases the % yield and increases the % drug entrapment. The optimal calculated parameters were polymer ratio (CMGK/CH) 2.13 and drug loading 50 (%w/w). The optimized batch of carboxymethyl gum katira-chitosan polyelectrolyte complex had yield of 69.04%, entrapment efficiency of ofloxacin 84.86%. Further, the optimized batch of carboxymethyl gum katira-chitosan polyelectrolyte complex releases ofloxacin 84.32% following Higuchi's square-root kinetics.

Evaluation of carboxymethyl moringa gum as nanometric carrier.

In the present study, carboxymethylation of Moringa oleifera gum was carried out by reacting with monochloroacetic acid. Modified gum was characterised employing Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and Rheology study. The carboxymethyl modification of moringa gum was found to increase its degree of crystallinity, reduce viscosity and swelling, increase the surface roughness and render its more anionic. The interaction between carboxymethyl moringa gum and chitosan was optimised by 2-factor, 3-level central composite experimental design to prepare polyelectrolyte nanoparticle using ofloxacin, as a model drug. The optimal calculated parameters were found to be carboxymethyl moringa gum- 0.016% (w/v), chitosan- 0.012% (w/v) which provided polyelectrolyte nanoparticle of average particle size 231nm and zeta potential 28mV. Carboxymethyl moringa gum-chitosan polyelectrolyte nanoparticles show sustained in vitro release of ofloxacin upto 6h which followed first order kinetics with mechanism of release being erosion of polymer matrix.

Carboxymethylation of Lepidium sativum polyuronide, its characterization and evaluation as a nanometric carrier.

Carboxymethylation of Lepidium sativum polyuronide was carried out to improve its functionality. Carboxymethyl modification was accomplished by reacting it with monochloroacetic acid under alkaline conditions, which yielded a product with degree of carboxymethyl substitution of 1.75. The results of characterization studies revealed that carboxymethylation of L. sativum polyuronide improves its flow property, changes compression behavior from elastic to plastic, diminishes its viscosity and swelling, and increases its crystallinity. The interaction between the anionic carboxymethyl lepidium polyuronide and Mg2+ ions was utilized to prepare ionically gelled nanoparticles employing ofloxacin as a model drug. A selected nanoparticulate formulation prepared by interaction between solutions of ofloxacin (0.1%, w/v) containing carboxymethyl lepidium polyuronide (0.15%, w/v) and magnesium chloride (0.05%, w/v) had particle size of 405nm and drug entrapment of 90.41%. On comparative evaluation, no significant difference was observed between the antibacterial activity of selected nanoformulation and conventional aqueous solution of ofloxacin. Further, the nanoparticulate formulation was observed to sustain the release of ofloxacin with 97% of the drug getting released over 12h. The release of ofloxacin from nanoformulation was found to follow first order kinetics with the mechanism of release being erosion of polymer matrix.

Carboxymethyl sesbania gum: Synthesis, characterization and evaluation for drug delivery.

In the present study, carboxymethyl Sesbania gum was synthesized and evaluated for drug delivery. Carboxymethylation was carried out by reacting with monochloroacetic acid under alkaline conditions. Modification of the gum was confirmed by Fourier-transform infrared spectroscopy. The degree of carboxymethyl substitution was determined to be 1.3. Carboxymethylation improved the flow properties, increased the degree of crystallinity and changed the compression behaviour from elastic to plastic. Further, the interaction between the modified gum and Ca2+-ions was optimized employing a 3-factor, 3-level central composite experimental design to prepare mucoadhesive sustained release beads using metformin hydrochloride as the model drug. The optimal calculated parameters were- concentrations of carboxymethyl Sesbania gum-2.5%(w/v), metformin hydrochloride- 50%(w/w) and calcium chloride- 15%(w/v), which provided beads with%yield of 160 and entrapment efficiency of 39.3%. The optimized batch of beads released, 68% of metformin over 12h, following the Higuchi's release kinetics with the mechanism of release being diffusion through the matrix.

Enhancement of anti-inflammatory activity of glycyrrhizic acid by encapsulation in chitosan-katira gum nanoparticles.

Efforts were made to improve the bioavailability and efficacy of Glycyrrhizic acid, a triterpentine saponin obtained from Glycyrrhiza glabra, having several pharmacological properties, by its encapsulation in biocompatible biopolymeric nanoparticles. Polycationic chitosan and polyanionic gum katira were used to prepare nanoparticles by ionic complexation method. Glycyrrhizic acid was loaded into the nanoparticles and was then examined for change in its in vivo anti-inflammatory activity against carrageenan-induced rat hind paw inflammation. The effects of concentrations of glycyrrhizic acid, chitosan and katira gum, upon particle size and encapsulation efficiency of glycyrrhizic acid were studied with the help of response surface methodology employing 3-factor, 3-level central composite experimental design. Particle size and encapsulation efficiency of optimized nanoparticulate formulation were 175.8nm and 84.77%, respectively. Particles were observed in transmission electron microscopy to be spherical in shape and 80nm in size. FTIR analysis indicated electrostatic interactions between carboxyl groups of ammonium glycyrrhizinate and amino groups of chitosan. In vitro drug release studies indicated that glycyrrhizic acid was released from the nanoparticles following zero-order kinetics and that there was a sustained release of the drug with 90.71% of it being released over a 12h period, and that the mechanism of release of glycyrrhizic acid from the nanoparticles was a combination of diffusion and erosion of the polymer matrix. In-vivo anti inflammatory efficacy of glycyrrhizic acid clearly improved upon encapsulation in chitosan-katira gum nanoparticles, by overcoming the limited bioavailability of its other forms.

Enhancement of anti-inflammatory activity of bromelain by its encapsulation in katira gum nanoparticles.

Bromelain-loaded katira gum nanoparticles were synthesized using 3 level optimization process and desirability approach. Nanoparticles of the optimized batch were characterized using particle size analysis, zeta potential, transmission electron microscopy and Fourier-transform infrared spectroscopy. Investigation of their in vivo anti-inflammatory activity by employing carrageenan induced rat-paw oedema method showed that encapsulation of bromelain in katira gum nanoparticles substantially enhanced its anti-inflammatory potential. This may be attributed to enhanced absorption owing to reduced particle size or to protection of bromelain from acid proteases.

Cubic liquid crystalline nanoparticles: optimization and evaluation for ocular delivery of tropicamide.

The purpose of this study was to investigate the potential of cubic liquid crystalline nanoparticles for ocular delivery of tropicamide. Ultrasound-assisted fragmentation of cubic liquid crystalline bulk phases resulted in cubic liquid crystalline nanoparticles employing Pluronic F127 as dispersant. The effects of process variables such as sonication time, sonication amplitude, sonication depth, and pre-mixing time on particle size and polydispersity index was investigated using central composite design. The morphology of tropicamide-loaded nanoparticles was found to be nearly cubical in shape by transmission electron microscopy observation. Further, small angle X-ray scattering experiment confirmed the presence of D and P phase cubic structures in coexistence. The optimized tropicamide-loaded cubic nanoparticles showed in vitro corneal permeation of tropicamide across isolated porcine cornea comparable to its commercial preparation, Tropicacyl®. Ocular tolerance was evaluated by Hen's egg-chorioallantoic membrane test and histological studies. The results of in vivo mydriatic response study demonstrated a remarkably higher area under mydriatic response curve (AUC0→1440 min) values of cubic nanoparticles over Tropicacyl® indicating better therapeutic value of cubic nanoparticles. Furthermore, tropicamide-loaded cubic nanoparticles exhibited prolonged mydriatic effect on rabbits as compared to commercial conventional aqueous ophthalmic solution.

Thiol derivatization of Xanthan gum and its evaluation as a mucoadhesive polymer.

Thiol-derivatization of xanthan gum polysaccharide was carried out by esterification with mercaptopropionic acid and thioglycolic acid. Thiol-derivatization was confirmed by Fourier-transformed infra-red spectroscopy. Xanthan-mercaptopropionic acid conjugate and xanthan-thioglycolic acid conjugate were found to possess 432.68mM and 465.02mM of thiol groups as determined by Ellman's method respectively. Comparative evaluation of mucoadhesive property of metronidazole loaded buccal pellets of xanthan and thiolated xanthan gum using chicken buccal pouch membrane revealed higher ex vivo bioadhesion time of thiolated xanthan gum as compared to xanthan gum. Improved mucoadhesive property of thiolated xanthan gum over the xanthan gum can be attributed to the formation of disulfide bond between mucus and thiolated xanthan gum. In vitro release study conducted using phosphate buffer (pH 6.8) revealed a sustained release profile of metronidazole from thiolated xanthan pellets as compared to xanthan pellets. In conclusion, thiolation of xanthan improves its mucoadhesive property and sustained the release of metronidazole over a prolonged period.