Pharmacokinetics and Histotoxic Profile of a Novel Azithromycin-Loaded Lipid-Based Nanoformulation.

Azithromycin traditional formulations possesses poor oral bioavailability which necessitates development of new formulation with enhanced bioavailability of the drug. The objective of current research was to explore the kinetics and safety profile of the newly developed azithromycin lipid-based nanoformulation (AZM-NF). In the in-vitro study of kinetics profiling, azithromycin (AZM) release was assessed using dialysis membrane enclosing equal quantity of either AZM-NF, oral suspension of azithromycin commercial product (AZM-CP), or azithromycin pure drug (AZM-PD) in simulated intestinal fluid. The ex-vivo study was performed using rabbit intestinal segments in physiological salts solution in a tissue bath. The in-vivo study was investigated by oral administration of AZM to rabbits while taking blood samples at predetermined time-intervals, followed by HPLC analysis. The toxicity study was conducted in rats to observe histopathological changes in rat's internal organs. In the in-vitro study, maximum release was 95.38 ± 4.58% for AZM-NF, 72.79 ± 8.85% for AZM-CP, and 46.13 ± 8.19% for AZM-PD (p < 0.0001). The ex-vivo investigation revealed maximum permeation of 85.68 ± 5.87 for AZM-NF and 64.88 ± 5.87% for AZM-CP (p < 0.001). The in-vivo kinetics showed Cmax 0.738 ± 0.038, and 0.599 ± 0.082 µg/ml with Tmax of 4 and 2 h for AZM-NF and AZM-CP respectively (p < 0.01). Histopathological examination revealed compromised myocardial fibers integrity by AZM-CP only, liver and kidney showed mild aberrations by both formulations, with no remarkable changes in the rest of studied organs. The results showed that AZM-NF exhibited significantly enhanced bioavailability with comparative safer profile to AZM-CP investigated.

Blood pressure lowering, vasodilator and cardiac-modulatory potential of Carum roxburghianum seed extract.

In current study, we describe blood pressure (BP)-lowering, endothelium-dependent, and independent vasodilator and cardio-modulatory actions of Carum roxburghianum seed. The crude extract of C. roxburghianum seed (Cr.Cr) induced dose-dependent (10-100 mg/kg) fall in arterial BP of anaesthetized rats. In isolated rabbit aorta, Cr.Cr (0.3-10 mg/mL) inhibited high K+ (80 mM) and phenylephrine (PE, 1 µM)-induced contractions, like verapamil and papaverine. In endothelium-intact rat aortic preparations, Nω-nitro-L-arginine methyl ester hydrochloride-sensitive vasodilator activity was observed with Cr.Cr, which also relaxed endothelium-denuded aorta tissues. In guinea-pig atria, Cr.Cr initially caused mild cardiac stimulation, followed by inhibition, as shown by papaverine. These results reveal that cardiovascular effects of C. roxburghianum seed extract are mediated possibly through combination of Ca++ antagonist, nitric oxide modulating and phosphodiesterase inhibitory mechanisms, though further in-depth studies are required for elucidating precise mode of action.

Insight into the bronchodilator activity of Vitex negundo.

CONTEXT: Vitex negundo Linn. (Verbenaceae) is traditionally used in hyperactive respiratory disorders. OBJECTIVE: This study explored the mechanisms underlying the effectiveness of Vitex negundo in hyperactive respiratory disorders. MATERIALS AND METHODS: Crude extract of V. negundo leaves was obtained. For in vivo bronchodilatory activity in anesthetized rats, different doses (1, 3, 10, 30, and 50 mg/kg) of the crude extract of V. negundo (Vn.Cr) were tested. The underlying mechanisms were studied in isolated guinea pig tracheal strips, suspended in organ baths at 37 °C. RESULTS: Intravenous doses of the crude extract of Vn.Cr showed dose-dependent bronchodilatory effect (9-50%) against carbachol (CCh; 100 µg/kg)-induced bronchoconstriction, similar to aminophylline. In isolated guinea-pig tracheal strips, Vn.Crrelaxed CCh (1 µM) and high K(+) pre-contractions with respective EC50 values of 0.72 (0.48-1.10; n = 5) and 3.38 mg/mL (1.84-6.21; n = 4), similar to papaverine. Diltiazem also relaxed both contractions with more potency against high K(+) pre-contraction (p < 0.05). Pre-incubation of the tracheal strips with Vn.Cr potentiated the isoprenaline inhibitory concentration response curves (CRCs), similar to papaverine. DISCUSSION: The inhibitory effect against CCh and high K(+) suggests involvement of phosphodiesterase (PDE) inhibitory pathway(s), in addition to an inhibitory effect on Ca(++) entry. This finding was further strengthened when pre-treatment of the tracheal strips potentiated the isoprenaline CRCs. CONCLUSION: RESULTS suggest Vn.Cr possesses a combination of papaverine-like PDE inhibitor and diltiazem-like Ca(++) entry blocking constituents, which partly explain its bronchodilatory effect, thus validating its medicinal importance in asthma.

Pharmacological basis for medicinal use of Lens culinaris in gastrointestinal and respiratory disorders.

Crude extract of Lens culinaris (Lc.Cr), which tested positive for presence of anthraquinones, flavonoids, saponins, sterol, tannins, and terpenes exhibited protective effect against castor oil-induced diarrhea in mice at 100-1000 mg/kg. In rabbit jejunum preparations, Lc.Cr caused relaxation of spontaneous contractions at 0.03-5.0 mg/mL. Lc.Cr inhibited carbachol (CCh, 1 µM) and K(+) (80 mM)-induced contractions in a pattern similar to dicyclomine, but different from verapamil and atropine. Lc.Cr shifted the Ca(++) concentration-response curves to the right, like dicyclomine and verapamil. Pretreatment of tissues with Lc.Cr (0.03-0.1 mg/mL) caused leftward shift of isoprenaline-induced inhibitory CRCs, similar to papaverine. In guinea-pig ileum, Lc.Cr produced rightward parallel shift of CCh curves, followed by non-parallel shift at higher concentration with suppression of maximum response, similar to dicyclomine, but different from verapamil and atropine. Lc.Cr (3.0-30 mg/kg) caused suppression of carbachol (CCh, 100 µg/kg)-induced increase in inspiratory pressure of anesthetized rats. In guinea-pig trachea, Lc.Cr relaxed CCh and high K(+) -induced contractions, shifted CCh curves to right and potentiated isoprenaline response. These results suggest that L. culinaris possesses antidiarrheal, antispasmodic, and bronchodilator activities mediated possibly through a combination of Ca(++) antagonist, anticholinergic, and phosphodiesterase inhibitory effects, and this study provides sound mechanistic background to its medicinal use in disorders of gut and airways hyperactivity, like diarrhea and asthma.

Nature cures nature: Hypericum perforatum attenuates physical withdrawal signs in opium dependent rats.

CONTEXT: Hypericum perforatum Linn. (Hypericaceae) (St. John's wort) attenuates opium withdrawal signs. AIM: To explore the therapeutic potential of Hypericum perforatum in the management of opium-induced withdrawal syndrome. MATERIALS AND METHODS: The effect of the Hypericum perforatum hydro-ethanol extract was investigated for potential to reverse naloxone (0.25 mg/kg)-induced opium withdrawal physical signs. Rats received opium extract (80-650 mg/kg) twice daily for 8 days along with Hypericum perforatum (20 mg/kg, orally) twice daily in chronic treatment and the same single dose 1 h before induction of withdrawal syndrome in the acute treated group. RESULTS: Hypericum perforatum reduced stereotype jumps and wet dog shake number in the chronic treatment compared to the saline control group (F(2, 24) = 3.968, p < 0. 05) and (F(2, 24) = 3.689, p < 0.05), respectively. The plant extract in the acutely treated group reduced diarrhea (F(2, 24) = 4.850, p < 0. 05 vs. saline). It decreased rectal temperature by chronic treatment at 30 min (F(2, 24) = 4.88, p < 0.05), 60 min (F(2, 240 = 5.364, p < 0.01) and 120 min (F(2, 24) = 4.907, p < 0.05). DISCUSSION AND CONCLUSION: This study reveals that the extract of Hypericum perforatum attenuates some physical signs of opium withdrawal syndrome possibly through direct or indirect interaction with opioid receptors. Further study is needed to clarify its mechanism.

Cardiovascular effects of Juniperus excelsa are mediated through multiple pathways.

Juniperus excelsa Bieb. is used in folk medicine for lowering blood pressure (BP). Its BP-lowering effect, endothelium-dependent and endothelium-independent vasodilator effects, and cardio-modulatory effect are reported here. The crude extract of J. excelsa (Je.Cr) which tested positive for the presence of anthraquinone, flavonoids, saponins, sterols, terpenes, and tannins induced a dose-dependent (10-300 mg/kg) fall in the arterial BP of anesthetized rats. In isolated rabbit aorta, Je.Cr (0.01-5.0 mg/mL) inhibited high K(+) (80 mM)- and phenylephrine (1 µM)-induced contractions, like that caused by verapamil and papaverine. In endothelium-intact rat aortic preparations, N(ω)-nitro-l-arginine methyl ester hydrochloride-sensitive vasodilator activity was noted from Je.Cr, which also relaxed the endothelium-denuded aorta tissues. In guinea pig atria, Je.Cr initially caused mild cardiac stimulation, followed by inhibition, like that exhibited by papaverine. Je.Cr prolonged the R-R interval in electrocardiogram of rats under anesthesia. These results reveal that cardiovascular effects of J. excelsa are mediated possibly through a combination of Ca(++) antagonism, nitric oxide-modulating mechanism, and phosphodiesterase inhibitory mechanism, which explain its medicinal use in hypertension.

Antispasmodic, bronchodilator and blood pressure lowering properties of Hypericum oblongifolium--possible mechanism of action.

The crude extract of Hypericum oblongifolium (Ho.Cr), which tested positive for flavonoids, saponins and tannins caused concentration-dependent (0.1-1.0 mg/mL) relaxation of spontaneous and high K(+) (80 mM)-induced contractions in isolated rabbit jejunum preparations, suggesting a Ca(++) antagonistic effect, which was confirmed when pretreatment of the tissue with Ho.Cr produced a rightward shift in the Ca(++) concentration-response curves, like that caused by verapamil. Ho.Cr relaxed carbachol (1 microM) and high K(+)-induced contractions in guinea pig tracheal preparations. It caused a dose-dependent (3-100 mg/kg) fall in arterial blood pressure of rats under anesthesia. In isolated guinea pig atria, Ho.Cr caused inhibition of both atrial force and rate of spontaneous contractions. When tested in rabbit aortic rings, Ho.Cr exhibited a vasodilator effect against phenylephrine (1 microM) and high K(+)-induced contractions. These results indicate that Ho.Cr possesses gastrointestinal, respiratory and cardiovascular inhibitory effects, mediated via a Ca(++) antagonist mechanism.

Transport of trans-activator of transcription (TAT) peptide in tumour tissue model: evaluation of factors affecting the transport of TAT evidenced by flow cytometry.

OBJECTIVES: Trans-activator of transcription (TAT), a cell penetrating peptide, has been explored to overcome resistance to penetration and transport inside the cell, therefore, suggested to be used as drug delivery vector into drug-resistant tumours. The generosity of this study was to evaluate modifiable factors (concentration, temperature, incubation time and spheroid age) on the penetration of TAT. METHODS: Multicellular tumour spheroids (MCTS) used as tumour tissue models to mimic some characteristics with in-vivo tumors. Cell monolayer and 3-, 5-, 7-day-old MCTS were incubated with TAT and effects of modifiable factors were determined quantitatively through flow cytometry, based on TAT-positive cell count (%) and mean fluorescence intensity. KEY FINDINGS: Enhancing TAT concentration (1, 5 and 25 µm), transport significantly increased (ANOVA, P < 0.0001) in cell monolayer and spheroids. However, rising temperature from 7 to 37°C (t, P > 0.05) and increasing incubation time; 20 min, 1 h and 3 h; (ANOVA, P > 0.05) were statistically non-significant. Moreover, TAT penetration declines as spheroids get older (ANOVA, P < 0.01). CONCLUSION: While exploiting MCTS as tumour tissue model, older spheroids could be preferred to target penetration-resistant cells and mimic the in-vivo microenvironment.

Evaluation of Paeonia emodi for its cardioprotective potentials: An investigative study towards possible mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Paeonia emodi Wall. ex Royle (peony) is an important member of family Paeoniaceae. Different parts of the plant have been folklorically used for treatment of different diseases. Infusion of dried flowers is used to treat diarrhea, the seeds are emetic and cathartic while the rhizome has been indicated for the treatment of hysteria, abdominal spasm, nervine tonic and headache. Besides these, peony has also been used in different respiratory and cardiovascular diseases (CVDs) like hypertension, palpitations, congestive heart failure and atherosclerosis. Being a folkloric remedy for the treatment of CVDs, Paeonia emodi (P. emodi) requires to be explored scientifically for MI management. AIM: The current research work was designed to explore the possible cardioprotective mechanism of P. emodi in Isoproterenol hydrochloride (ISO) induced MI in mice. MATERIALS AND METHODS: Experimental animals randomly divided in different groups, received methanolic extract of P. emodi (Pe.ME) and its subsequent fractions for 15 days followed by ISO (100 mg/kg s.c) at 24 h interval for two days. The cardioprotective potential of the test samples were investigated by determining the serum levels of Alanine Amino Transferase (ALT), Aspartate Amino Transferase (AST), Lactate Dehydrogenase (LDH) and Creatine Phosphokinase (CPK). The ethyl acetate fraction (Pe.EA) was found potent among all the tested samples of P. emodi. Based on its high potency, Pe.EA was subjected to GC-MS analysis and further relevant experiments including anti-hyperlipidemic, antioxidant, lipid peroxidation, membrane stabilization, thrombolytic, DNA ladder assay and histopathological study. RESULTS: Pe.EA exhibited significant cardioprotective activity through reduction in levels of serum biomarkers responsible for MI. It significantly reduced serum levels of ALT (p < 0.001), AST (p < 0.001), CPK (p < 0.05) and LDH (p < 0.001) at a dose of 300 mg/kg as compared to ISO treated group. The GC-MS analysis confirmed the presence of potential compounds (esculetin, methyl eugenol, isovanillic acid) which might play a role in cardioprotection. Further screening confirmed that the effect of Pe.EA is mediated through multiple targets/mechanisms, which include anti-hyperlipidemia, antioxidant, lipid peroxidation inhibition, membrane stabilization, thrombolytic and DNA protective effects. Histopathological studies revealed the palliative effect for the damage caused in myocardial tissues. CONCLUSION: Findings of current study provide evidence that P. emodi is a potential candidate for the treatment and management of MI.

Fabrication of Niclosamide loaded solid lipid nanoparticles: in vitro characterization and comparative in vivo evaluation.

Niclosamide (NCS) is an oral anthelminthic drug having low solubility and hence low bioavailability. Current investigation shows an approach to fabricate solid lipid nanoparticles (SLNs) of NCS and evaluated for pharmaceutical, in vitro and in vivo characterization. NFM-3 showed particle size 204.2 ± 2.2 nm, polydispersity index 0.328 ± 0.02 and zeta potential -33.16 ± 2 mV. Entrapment efficiency and drug loading capacity were 84.4 ± 0.02% and 5.27 ± 0.03%, respectively. Scanning electron microscopy image indicated that particles were nanoranged. DSC and P-XRD results showed change in physicochemical properties of NCS. FT-IR spectra confirmed compatibility between NCS and excipients. The drug release profile showed sustained release (93.21%) of NCS in 12 h. Different kinetic models showed zero-order kinetics and Case-II transport mechanism. Study showed maximum stability at refrigerated temperature. In vivo pharmacokinetic study showed 2.15-fold increase in NCS peak plasma concentration as solid lipid nanoparticle formulation (NFM-3) compared to commercial product while relative bioavailability was 11.08. Results including in vitro and in vivo release studies of NCS confirmed that SLNs system is suitable to improve oral delivery of NCS with increased aqueous solubility, permeability and finally bioavailability.

Antispasmodic and bronchodilator activities of St John's wort are putatively mediated through dual inhibition of calcium influx and phosphodiesterase.

The crude extract of aerial parts of St John's wort (Hypericum perforatum) (Hp.Cr) and its fractions were studied in vitro for its possible spasmolytic and bronchodilator activities to rationalize some of its medicinal uses. In rabbit jejunum preparations, Hp.Cr caused a concentration-dependent relaxation of both spontaneous and K+ (80 mm)-induced contractions at a similar concentration range (0.1-1.0 mg/mL), similar to that produced by papaverine, whereas verapamil was relatively potent against K+-induced contractions. Hp.Cr shifted the Ca2+ concentration-response curves (CRCs) to the right, similar to that caused by papaverine or verapamil and also caused leftward shift of isoprenaline-induced inhibitory CRCs, similar to papaverine. In guinea-pig tracheal preparations, Hp.Cr caused relaxation of carbachol and K+-induced contractions at similar concentrations (0.01-0.3 mg/mL) and also shifted the isoprenaline-induced inhibitory CRCs to the left, similar to that caused by papaverine. In rabbit aorta preparations at rest, Hp.Cr produced a moderate vasoconstriction, while exhibited vasodilator effect against phenylephrine and K+-induced contractions. Papaverine and verapamil also produced similar non-specific vasodilation, but were devoid of any vasoconstrictor effect. Hp.Cr caused suppression of atrial force of contractions at concentrations about 20 times higher than those that produced inhibitory effect in smooth muscle preparations, similar to papaverine. These results suggest that the spasmolytic effects of Hp.Cr are mediated through dual inhibition of calcium influx and phosphodiesterase (PDE)-like mechanisms, which might explain the medicinal use of St John's wort in the disorders of gastrointestinal and respiratory tracts. Furthermore, the presence of Ca2+ antagonist and PDE inhibitory-like constituents might also be contributing to some extent in the well established use of plant in depression.

Pharmacological explanation for the medicinal use of Juniperus excelsa in hyperactive gastrointestinal and respiratory disorders.

Crude extract of Juniperus excelsa (JeExt), which tested positive for the presence of anthraquinone, flavonoids, saponins, sterols, terpenes and tannin, exhibited a protective effect against castor oil-induced diarrhoea in mice at 100-1000 mg/kg. In rabbit jejunum preparations, JeExt (0.01-1.0 mg/mL) caused relaxation of spontaneous and K(+) (80 mM)-induced contractions at similar concentrations to papaverine, whereas verapamil was relatively more potent against K(+). JeExt (0.03-0.3 mg/mL) shifted Ca(2+) concentration-response curves to the right, like papaverine or verapamil. JeExt (0.003-0.01 mg/mL) caused a leftward shift of isoprenaline-induced inhibitory concentration-response curves, similar to papaverine. JeExt (1.0-30 mg/kg) caused suppression of carbachol (CCh, 100 µg/kg)-induced increase in inspiratory pressure of anaesthetized rats. In guinea-pig trachea, JeExt (0.001-3.0 mg/mL) relaxed CCh (1 µM)- and high K(+)-induced contractions and shifted isoprenaline-induced inhibitory curves to the left. This study suggests that Juniperus excelsa possibly exhibits a combination of Ca(2+) antagonist and phosphodiesterase inhibitory effects, which provides a pharmacological basis for its traditional use in disorders of gut and airways hyperactivity, such as diarrhoea, colic and asthma.

Gut and airways relaxant effects of Carum roxburghianum.

ETHNOPHARMACOLOGICAL RELEVANCE: Carum roxburghianum is traditionally used in hyperactive gastrointestinal and respiratory disorders. The present study was carried out to investigate the possible gut and airways relaxant potential of Carum roxburghianum to rationalize its folk uses. MATERIALS AND METHODS: Crude extract of Carum roxburghianum (Cr.Cr) was studied in in vivo and in vitro techniques. RESULTS: Cr.Cr exhibited protective effect against castor oil-induced diarrhea in mice at 100-1000 mg/kg. In rabbit jejunum preparations, Cr.Cr (0.03-3.0 mg/mL) caused relaxation of spontaneous and K(+) (80 mM)-induced contractions at similar concentrations, like papaverine. Pretreatment of tissues with Cr.Cr (0.1-1.0 mg/mL) shifted Ca(++) concentration-response curves (CRCs) to right, like verapamil. Cr.Cr (0.03 and 0.1 mg/mL) caused leftward shift of isoprenaline-induced inhibitory CRCs, similar to papaverine. In isolated guinea-pig ileum, Cr.Cr (0.01 and 0.03 mg/mL) produced rightward parallel shift of acetylcholine-curves, like atropine. Cr.Cr (1.0-30 mg/kg) caused suppression of carbachol (CCh, 100 µg/kg)-induced increase in inspiratory pressure of anaesthetized rats. In guinea-pig trachea, Cr.Cr (0.03-1.0 mg/mL) relaxed CCh and high K(+)-induced contractions, shifted isoprenaline-induced inhibitory CRCs to left at 0.1 and 0.3 mg/mL and CCh-curves parallel to right (0.01 and 0.03 mg/mL). Cr.Cr did not cause any mortality of mice up to 10 g/kg dose. CONCLUSION: These results indicate that Carum roxburghianum possess combination of antidiarrheal, antispasmodic and bronchodilatory effects, which provides pharmacological basis to its traditional use in the disorders of gut and airways hyperactivity, like diarrhea, colic and asthma.