Design, characterization, and evaluation of aceclofenac-loaded Eudragit RS 100 nanoparticulate system for ocular delivery.

The aim of the present study was to develop and evaluate positively charged nanoparticles of aceclofenac for ocular delivery. The nanoparticles were prepared by the nanoprecipitation method using Eudragit RS 100. The optimized nanoparticles were found to have narrow particle size range (238.9 ± 8 nm) with nearly spherical shape, positive zeta potential (40.3 ± 3.8). Higher entrapment efficiency of aceclofenac (94.53 ± 1.0%) with prolonged in vitro drug release profiles was also observed. Powder X-ray diffraction and differential scanning calorimetry studies indicated decrease in crystallinity of drug within the nanoparticulate polymeric matrix. The formulation was found to have higher permeation as compared to aceclofenac aqueous solution. Nanoparticle formulation was found to be quite stable and well tolerated with no signs of corneal damage. The in vivo studies involving the arachidonic acid-induced ocular inflammation in rabbits showed optimal efficacy of the nanoparticles with significantly higher inhibition of polymorphonuclear leukocytes migration (p < 0.05) and lid closure scores.

Aceclofenac oil drops: characterization and evaluation against ocular inflammation.

Ocular inflammatory diseases, such as uveitis, scleritis, episcleritis and dry eye syndrome are commonly treated with eye drop formulations. In the present study, attempts were made to prepare aceclofenac oil formulations to evaluate its transcorneal permeation and anti-inflammatory effect. Ophthalmic solutions of aceclofenac with or without (0.5% v/v) benzyl alcohol were formulated in different vegetable oils and permeation studies were carried out. Aceclofenac ophthalmic solution in linseed oil containing benzyl alcohol exhibited maximum permeation (4.42% in goat, 4.26% in sheep and 3.94% in buffalo) through corneas under study. The partition characteristics of aceclofenac in linseed oil reinforced the results of permeation studies. The optimized formulation (linseed oil containing benzyl alcohol) showed better stability profile. Linseed oil aceclofenac formulation showed significant inhibitory effect on ocular inflammation induced by arachidonic acid in rabbit eyes (p < .05) and hence it can be considered as a potential approach for treatment of ocular inflammatory conditions.

Design and evaluation of acrylate polymeric carriers for fabrication of pH-sensitive microparticles.

Colon-targeted microparticles loaded with a model anti-inflammatory drug were fabricated using especially designed acrylic acid-butyl methacrylate copolymers. Microparticles were prepared by oil-in-oil solvent evaporation method using Span 80 as emulsifier. Microparticles were found to be spherical in shape, hemocompatible and anionic with zeta potential of -27.4 and -29.0 mV. Entrapment of drug in the microparticles was confirmed by Fourier transform infrared (FTIR) spectroscopy. However, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) revealed amorphous nature of microparticles due to the dilution effect of amorphous polymer. The microparticles released less than 5% drug at pH 1.2, while more than 90% of the drug load was released at pH 7.4. This suggested the colon targeting nature of the formulations. In experimentally developed colitis in Wistar rats, the microparticle formulation showed significant reduction (p < .05) in the disease activity score (disease symptoms), the colon-to-body weight ratio (tissue edema) and the myeloperoxidase, tumor necrosis factor (TNF)-α and interleukin (IL)-1ß activities.

Formulation and characterization of clozapine and risperidone co-entrapped spray-dried PLGA nanoparticles.

In the current study, polylactide-co-glycolide (PLGA) nanoparticles entrapping both clozapine (CLZ) and risperidone (RIS) were formulated by spray-drying using Buchi Nano Spray Dryer B-90 (Flawil, Switzerland). Parameters such as inlet temperature, spray mesh diameter, sample flow rate, spray rate and applied pressure were optimized to produce nanoparticles having desired release profile using both low- and high-molecular weight PLGA polymer. Smallest size nanoparticle of size around 248 nm could be prepared using a 4.0 µm mesh diameter with low-molecular weight polymer. The load of CLZ and RIS was 126.3 and 58.2 µg/mg of polymer particles, respectively. Entrapment efficiency of drugs in PLGA nanoparticles was 94.74% for CLZ and 93.12% for RIS. Both the drugs released continuously from the nanoparticle formulations. PLGA nanoparticles formulated using low-molecular weight polymer released around 80% of the entrapped drug over 10 days of time. Nature of drug inside polymer particles was amorphous, and there was no chemical interaction of CLZ and RIS with polymer. Polymeric nanoparticles were found to be non-toxic in nature using PC12 cell line. This nanospray drying process proved to be suitable for developing polymeric nanoformulation delivering dual drugs for the treatment of Schizophrenia.

Development and characterization of itraconazole-loaded solid lipid nanoparticles for ocular delivery.

The purpose of this study was to investigate the feasibility of entrapping water-insoluble drug itraconazole into solid lipid nanoparticles (SLNs) for topical ocular delivery. The drug-loaded SLNs were prepared from stearic acid and palmitic acid using different concentrations of polyvinyl alcohol employed as emulsifier. SLNs were prepared by the melt-emulsion sonication and low temperature-solidification method and characterized for particle size, zeta potential, drug loading and drug entrapment efficiency. The mean particle size of SLNs prepared with stearic acid ranged from 139 to 199 nm, while the SLNs prepared with palmitic acid had particle size in the range of 126-160 nm. The SLNs were spherical in shape. Stearic acid-SLNs showed higher entrapment of drug compared with palmitic acid-SLNs. Differential scanning calorimetry (DSC) and X-ray diffraction measurements showed decrease in crystallinity of drug in the SLN formulations. The modified Franz-diffusion cell and freshly excised goat corneas were used to test drug corneal permeability. Permeation of itraconazole from stearic acid-SLNs was higher than that obtained with palmitic acid-SLNs. The SLNs showed clear zone of inhibition against Aspergillus flavus indicating antimicrobial efficacy of formulations.

Development of enteric submicron particles formulation of α-amylase for oral delivery.

Enteric submicron particles (SPs) formulations of α-amylase were prepared by w/o/w emulsion solvent evaporation using hydroxypropyl methylcellulose phthalate (HPMCP) and Eudragit L 100, to avoid gastric inactivation of α-amylase. Smaller internal and external aqueous phase volume provided maximum encapsulation efficiency (71.92-73.40%), least particle size (546.4-595.4 nm) and 23-26% loss of enzyme activity. Release studies in 0.1 N HCl confirmed the gastro-resistance of formulations. The anionic SPs aggregated in 0.1 N HCl (i.e. gastric pH 1.2), due to protonation of carboxylic groups of enteric polymer. The aggregates being < 500 µm size would not impede gastric emptying. However, at pH >5.0 (duodenal pH), SPs showed de-aggregation due to restoration of surface charge. HPMCP and Eudragit L 100 SPs facilitated almost complete release of α-amylase within 30 min at pH 6.0 and 6.8, respectively, following Higuchi kinetics. PXRD and DSC indicated amorphous character and scanning electron microscope showed spherical shape of SPs. In simulated gastro-intestinal pH condition, HPMCP and Eudragit L 100 SPs showed good digestion of cooked rice and could serve as potential carrier for oral enzyme delivery. Stability studies indicated the formulations as quite stable to ensure 2 years shelf life at room temperature.

Soluplus--solubilized citrated camptothecin--a potential drug delivery strategy in colon cancer.

Camptothecin (CPT), a potent antitumor drug, exhibits poor aqueous solubility and rapid conversion from the pharmacologically active lactone form to inactive carboxylate form at physiological pH. Solid dispersion of CPT in Soluplus®, an amphiphilic polymeric solubilizer, was prepared to increase the aqueous solubility of CPT and the resultant solid dispersion along with citric acid was formulated as hard gelatin capsules that were subsequently coated with Eudragit S100 polymer for colonic delivery. FTIR spectrum of the solid dispersion confirmed the presence of CPT. PXRD and DSC revealed the semicrystalline nature of solid dispersion. The solubility of the drug was found to increase ~40 times in the presence of Soluplus and ~75 times in solid dispersion. The capsules showed no drug release in 0.01 N HCl but released 86.4% drug in lactone form in phosphate buffer (pH 7.4) and the result appears to be due to citric acid-induced lowering of pH of buffer from 7.4 to 6.0. Thus the presence of citric acid in the formulation led to stabilization of the drug in its pharmacologically active lactone form. Cytotoxicity studies conducted with the formulation of solid dispersion with citric acid, utilizing cell cytotoxicity test (MTT test) on Caco-2 cells, confirmed cytotoxic nature of the formulation.

Acrylic acid-methyl methacrylate (2.5:7.5/2:8) enteric copolymer for colon targeted drug delivery.

Enteric copolymers of acrylic acid and methyl methacrylate (2.5:7.5 and 2:8) were prepared using tetrahydrofuran as solvent and AIBN as free radical initiator for colon targeting. FTIR and (1)H NMR spectra of the copolymers showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. Flurbiprofen sodium microspheres (M1 and M2) made with the copolymers, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -57.8 and -53.7 mV) and contained 5.47 and 5.89% drug. FTIR spectrum of microspheres showed peaks for aromatic C = C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. PXRD revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26°C against broad endotherms of copolymers and microspheres. The microspheres released 43 and 36% drug at pH 6.8 in 2 h and 99 and 96% at pH 7.4 in next 3-4 h.The microspheres did not adhere on gastric-mucosa at pH 1.2 but showed mucoadhesion time of 18 min and 9 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in colon, suggesting the potential of the hemocompatible copolymers for pH dependent colon targeted drug delivery system.

Diclofenac-loaded Eudragit S100 nanosuspension for ophthalmic delivery.

In this study, diclofenac-loaded Eudragit S100-based nanosuspension was prepared by nanoprecipitation method and characterised for particle size, morphology, in vitro release, and for its in vivo ocular anti-inflammatory activity. The diclofenac-loaded Eudragit S100 nanosuspension was found to have a particle size of 172 nm, polydispersibility index of 0.14 and zeta potential of -23.7 +/- 6.07 mV, indicating that the nanosuspension is fairly stable. The nanosuspended particles were found to be spherical in shape. The nanosuspension was found to provide a sustained in vitro release, following the Higuchi square-root release kinetics. The results indicated that the nanosuspension released the drug by combination of dissolution and diffusion. The in vivo evaluation of nanosuspension in PGE(2)-induced ocular inflammation in rabbit model revealed a significantly (p < 0.05) higher inhibition of PGE(2)-induced polymorphonuclear leukocytes migration and lid-closure scores as compared with the aqueous solution of diclofenac.

Linum usitatissimum (linseed/flaxseed) fixed oil: antimicrobial activity and efficacy in bovine mastitis.

PURPOSE: In vitro antimicrobial activity and in vivo therapeutic efficacy of L. usitatissimum (linseed/flaxseed) fixed oil in bovine mastitis were investigated. METHOD: In vitro antimicrobial activity of L. usitatissimum fixed oil was evaluated against a number of microorganisms by disc diffusion method and MIC determination. The in vivo efficacy of the oil was evaluated in nine mastitis-affected cows divided into three groups (three in each group), following once-a-day intramammary infusion of oil, cefoperazone or an oil-cefoperazone combination for 7 days and by monitoring the California mastitis test score, somatic cell count and microbial count in milk samples. RESULTS: The in vitro antimicrobial activity of the oil against Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli was comparable to that of cefoperazone while the antimicrobial activity against Enterococcus faecalis, Micrococcus luteus and Candida albicans, was greater than that of cefoperazone. In the in vivo study, the oil exhibited significant reduction in the California mastitis test score and somatic cell count in milk samples from infected udders following 7 days of intramammary administration suggesting its anti-inflammatory effect. The microbial count in milk samples was also reduced significantly following oil treatment. The effects were comparable to the treatment by cefoperazone (Mastiwock) alone or in combination with the oil. Apparently, the anti-inflammatory and antimicrobial properties of the oil contribute to its therapeutic efficacy in mastitis; the oil could be used as an alternative treatment for bovine mastitis CONCLUSION: The results suggest possible therapeutic potential of L. usitatissimum fixed oil in bovine mastitis.

Anti-inflammatory, analgesic and antipyretic activities of Linum usitatissimum L. (flaxseed/linseed) fixed oil.

The fixed oil of L. usitatissimum (flaxseed/linseed) inhibited PGE2-, leukotriene-, histamine- and bradykinin-induced inflammation. The oil also inhibited arachidonic acid-induced inflammation, suggesting its capacity to inhibit both cyclooxygenase and lipoxygenase pathways of arachidonate metabolism. In tail immersion model, the oil raised the pain threshold to a lesser extent than morphine but showed excellent peripherally acting, analgesic activity comparable to aspirin, against acetic acid-induced writhing in mouse. In typhoid paratyphoid A/B vaccine-induced pyrexia, the oil showed antipyretic activity comparable to aspirin. The oil contains 57.38% alpha-linolenic acid. Dual inhibition of arachidonic acid metabolism, antihistaminic and antibradykinin activities of the oil could account for the biological activity and the active principle could be alpha-linolenic acid an omega-3 (18:3, n-3) fatty acid.

Acrylic acid-methyl methacrylate copolymer for oral prolonged drug release.

Acrylic acid (AA)-methyl methacrylate (MMA) based copolymers, in different molar ratios (3:7, 4:6, 5:5, 6:4, and 7:3) were synthesized using tetrahydrofuran as solvent and AIBN as free radical initiator. Increase in acrylic acid concentration promoted pH-dependent swelling of copolymer and copolymer AA:MMA (3:7) was selected due to minimum swelling. ATR/FTIR and (1)H NMR spectra of the copolymer showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. The copolymer was hemocompatible. Flurbiprofen sodium microspheres made with the copolymer, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -59.0 mV) and contained 4.53% drug. ATR spectrum of microspheres showed peaks for aromatic C=C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. XRD analysis revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26 degrees C against broad endotherms of copolymer and microspheres having peaks at 82.24 and 86.59 degrees C, respectively. The thermogram of microspheres did not show the melting peak of flurbiprofen. The microspheres exhibited no drug release at pH <6.8 and released 83.4 and 99% drug at pH 6.8 and 7.4 in 3 h. The microspheres did not adhere on gastric mucosa at pH 1.2 but showed mucoadhesion time of 28 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in distal ileum, suggesting the potential of the hemocompatible copolymer for enteric coating for prolonged drug release.

Eudragit S-100 entrapped chitosan microspheres of valdecoxib for colon cancer.

COX-2 inhibitors have demonstrated beneficial effects in colorectal cancer. The purpose of this study was to prepare and evaluate the colon specific microspheres of COX-2 inhibitors using valdecoxib as a model drug. Mucoadhesive core microspheres were prepared using chitosan as polymer and entrapped within Eudragit S 100 for colon targeting. FTIR spectrum of selected, coated microspheres showed peaks of valdecoxib at 3377, 3250, 1334 and 1155 cm(-1). XRD showed amorphous character and DSC showed depressed broad endotherm of valdecoxib at 169.07 degrees C, which may be attributed to dilution effect by the amorphous polymer. The coated microspheres were spherical with an average size of 90 mum. Storage of the microspheres at 40 degrees C/75% relative humidity for 6 months indicated no significant drug degradation. The coated microspheres did neither release the drug in acidic pH of stomach (pH 1.2) nor in small intestinal pH between 5 to 6.8, and the release started at pH 7.4, indicting perfect colonic delivery. The coated microspheres pretreated with phosphate buffer pH 7.4 for 30 min, when applied to mucosal surface of freshly excised goat colon, showed good mucoadhesion. The drug release at pH 7.4 and good mucoadhesive property of the microspheres make the system ideal for colonic delivery.

Abattoir-sourced isolated ileum from Gallus gallus domesticus as an experimental tool.

A study was undertaken to determine the longevity of active muscarinic receptors on abattoir-sourced isolated ileum preparations from Gallus gallus domesticus, with a view to using the tissue as an experimental tool for functional response assays in laboratory experiments. A concentration-response curve for acetylcholine (1-256 µM) was plotted, in the presence and absence of 1, 3 and 6 nM atropine. In a second experiment, unknown concentrations of acetylcholine samples were determined by using an interpolation method. In this experiment, four sample concentrations were used and the calculated values were found to be almost equal to the actual values. Finally, an experiment was carried out to elucidate the effects of post-sacrifice time on the contractile response of the tissue. The results showed that the tissue maintained considerable contractile response at the 6-hour post-sacrifice time-point. Competitive antagonistic activity was observed between acetylcholine and atropine on the chicken ileum, and the pA2 value was calculated to be 9.21 by using an Arunlakshana-Schild plot. The results suggest that isolated ileum preparations of Gallus gallus domesticus, obtained from a meat abattoir, can be used as a basic experimental tool for bioassays in routine laboratory experiments. However, its potential as a research tool still needs to be confirmed.

Therapeutic effect of Linum usitatissimum (flaxseed/linseed) fixed oil on acute and chronic arthritic models in albino rats.

The present study was undertaken to assess the activity/anti-inflammatory potential of Linum usitatissimum fixed oil against castor oil-induced diarrhoea, turpentine oil-induced joint oedema, formaldehyde and Complete Freund's Adjuvant (CFA)-induced arthritis in Wistar albino rats. The oil intraperitoneally, significantly inhibited the castor oil-induced diarrhoea and turpentine oil-induced exudative joint oedema in a dose-dependent manner. Significant inhibitory effect of L. usitatissimum fixed oil was observed in formaldehyde-induced proliferative global oedematous arthritis when given intraperitoneally, with significant checking of the serum glutamic oxaloacetic acid transaminase and serum glutamic pyruvic acid transaminase. Further, L. usitatissimum fixed oil showed a significant dose-dependent protective effect against CFA-induced arthritis as well. Secondary lesions produced by CFA due to a delayed hypersensitivity reaction were also reduced in a significant manner. Anti-inflammatory activity of L. usitatissimum fixed oil can be attributed to the presence of alpha linolenic acid (57.38%, an omega-3 fatty acid, 18:3, n-3) having dual inhibitory effect on arachidonate metabolism resulting in suppressed production of proinflammatory n-6 eicosanoids (PGE(2), LTB(4)) and diminished vascular permeability. These observations suggest possible therapeutic potential of L. usitatissimum fixed oil in inflammatory disorders like rheumatoid arthritis.

Evaluation of antiulcer and antisecretory potential of Linum usitatissimum fixed oil and possible mechanism of action.

The aim of the study was to evaluate the antiulcer activity of Linum usitatissimum fixed oil against aspirin-, indomethacin-, ethanol-, reserpine-, serotonin- and stress-induced gastric ulceration in rats and histamine-induced gastric ulceration in guinea pigs. Attempts were also made to evaluate the in vitro anticholinergic and antihistaminic activity and in vivo antisecretary and antiulcer activity of oil following pylorus ligation in rats. L. usitatissimum fixed oil exhibited significant antiulcer activity against different ulcerogens in experimental animal models. The fixed oil significantly inhibited acetylcholine- and histamine-induced contraction of guinea pig and rat ileums, respectively, suggesting its anticholinergic and antihistaminic activity. The oil also exhibited significant inhibitory effect on gastric secretion/total acidity and aspirin-induced gastric ulceration in pylorus-ligated rats. The lipoxygenase inhibitory, histamine antagonistic and antisecretory (anticholinergic) effects of the oil could probably have contributed towards antiulcer activity. L. usitatissimum fixed oil may be considered to be a drug of natural origin which possesses significant antiulcer activity. The present observation is the first experimental data showing antiulcer activity of L. usitatissimum fixed oil.

Is relief from diabetes just a breath away?

Pulmonary insulin delivery is steadily emerging as a promising solution for the treatment of diabetes mellitus. The large as well as thin absorptive area of the lungs has not been explored until now for the treatment of systemic disease like diabetes. With an understanding of the lung anatomy and physiology and the transport mechanism of insulin through lungs, diabetic treatment through the pulmonary route may well become the reality of the 21(st) century. Though the transport of insulin through the lungs itself appears quite encouraging, potential problems concerning the formulation of a peptide like insulin in the form of an aerosol seem to be the most challenging. Stability aspects, stringent control of Mass Median Aerodynamic Diameter, antigenicity, insulin losses due to the device and impaction, sedimentation and diffusion in the nonabsorptive areas of the airway system (especially in the oropharynx) emerge as major concerns. This is in addition to the problems of lack of reproducibility of dose delivery by an inhaler where individual variations due to inspiratory differences and method of use of device come into play. Lung diseases and smoking may alter lung mechanisms and dose alterations are to be studied in such cases. Though almost equally effective, if not more, than the subcutaneous insulin route, even with proved short-term efficacy, insulin delivery through lungs is a potential but not a wholly proven means for blood glucose control.

Biological activities of Ocimum sanctum L. fixed oil--an overview.

Seeds of Ocimum sanctum L. (Labiatae; popularly known as 'Tulsi' in Hindi and 'Holy Basil' in English) contain a pale yellow colored fixed oil. The oil possesses antiinflammatory activity due to dual inhibition of arachidonate metabolism supplemented by antihistaminic activity. The antiinflammatory activity is not dependent on the pituitary adrenal axis. The oil possesses antipyretic activity due to prostaglandin inhibition and peripherally acting analgesic activity. The oil has been found to be effective against formaldehyde or adjuvant induced arthritis and turpentine oil induced joint edema in animals. Lipoxygenase inhibitory, histamine antagonistic and antisecretory activities of the oil contribute towards antiulcer activity. The oil can inhibit enhancement of vascular capillary permeability and leucocyte migration following inflammatory stimulus. The LD50 of the oil is 42.5 ml/kg and long-term use of oil at 3 ml/kg dose does not produce any untoward effects in rats. The oil contains a-linolenic acid, an omega-3 fatty acid, which on metabolism produces eicosapentaenoic acid and the same appears to be responsible for the biological activity. The oil has hypotensive, anticoagulant and immunomodulatory activities. Antioxidant property of the oil renders metabolic inhibition, chemoprevention and hypolipidaemic activity. Presence of linolenic acid in the oil imparts antibacterial activity against Staphylococcus aureus. The oil alone or in combination with cloxacillin, a beta-lactamase resistant penicillin, has been found to be beneficial in bovine mastitis, an inflammatory disorder resulting from staphylococcal infection. Existence of anti-inflammatory, analgesic and antibacterial activities in single entity i.e. fixed oil appears to be unique.

Preparation and characterization of polyvinyl alcohol-gelatin hydrogel membranes for biomedical applications.

The purpose of this research was to design and develop hydrogels by esterification of polyvinyl alcohol (PVA) with gelatin. The membranes were characterized by Fourier Transform Infrared (FTIR) spectroscopy, x-ray diffraction (XRD), and differential scanning calorimetry. The viscosity of the esterified product (as solution) was compared with the mixture of PVA and gelatin of the same composition. The mechanical properties of the hydrogels were characterized by tensile tests. Swelling behavior and hemocompatibility of the membrane were also evaluated. The diffusion coefficient of salicylic acid (SA), when the receptor compartment contained Ringer's solution, through the membrane was determined. SA was used as a model drug. FTIR spectra of the membranes indicated complete esterification of the free carboxylic groups of gelatin. XRD studies indicated that the crystallinity of the membranes was mainly due to gelatin. The comparison of viscosity indicated an increase in segment density within the molecular coil. The membrane had sufficient strength and water-holding capacity. Hemocompatibility suggested that the hydrogel could be tried as wound dressing and as an implantable drug delivery system. The diffusion coefficient of SA through the membrane was found to be 1.32 x 10(-5) cm(2)/s. The experimental results indicated that the hydrogel could be tried for various biomedical applications.