Showing papers in "Journal of Pharmacy and Pharmacology in 2012"

Doxorubicin: an update on anticancer molecular action, toxicity and novel drug delivery systems

Abstract: Objectives The frontline drug doxorubicin has been used for treating cancer for over 30 years. While providing a cure in select cases, doxorubicin causes toxicity to most major organs, especially life-threatening cardiotoxicity, which forces the treatment to become dose-limiting. Key findings Doxorubicin is known to bind to DNA-associated enzymes, intercalate with DNA base pairs, and target multiple molecular targets to produce a range of cytotoxic effects. For instance, it causes the activation of various molecular signals from AMPK (AMP-activated protein kinase inducing apoptosis) to influence the Bcl-2/Bax apoptosis pathway. By altering the Bcl-2/Bax ratio, downstream activation of different caspases can occur resulting in apoptosis. Doxorubicin also induces apoptosis and necrosis in healthy tissue causing toxicity in the brain, liver, kidney and heart. Over the years, many studies have been conducted to devise a drug delivery system that would eliminate these adverse affects including liposomes, hydrogel and nanoparticulate systems, and we highlight the pros and cons of these drug delivery systems. Summary Overall the future for the continued use of doxorubicin clinically against cancer looks set to be prolonged, provided certain enhancements as listed above are made to its chemistry, delivery and toxicity. Increased efficacy depends on these three aims being met satisfactorily as discussed in turn in this review.

Ethnobotanical and scientific aspects of malva sylvestris l.: a millennial herbal medicine

Abstract: Objectives Malva sylvestris L., known as common mallow, is native to Europe, North Africa and Asia. In the Mediterranean region, this species has a long history of use as food, and due to its therapeutic relevance, some parts of this plant have been employed in traditional and ethnoveterinary medicines. The leaves in particular have been reported to have potent anti-inflammatory, antioxidant, anti-complementary, anticancer and skin tissue integrity activity. Additionally, an anti-ulcerogenic effect was recently proven, demonstrating that the aqueous extract was more effective than cimetidine, a potent medicine used to treat gastric ulcers. Due to its wide use and medicinal importance, many studies have been conducted; however, the information in the literature is very extensive and disseminated, making it difficult to use. Key findings A complete review involving the ethnobotanical and scientific aspects of M. sylvestris has been made. The research has provided evidence that M. sylvestris has potential use as a medicinal plant and has highlighted a need for more studies involving clinical and toxicological aspects of its use. Summary This review can contribute to the field with its historical context, and by describing the progress made, new ideas for researchers can arise.

Engineered PLGA nano- and micro-carriers for pulmonary delivery: challenges and promises.

Abstract: Objectives The aim of this review is to summarize the current state-of-the-art in poly(lactic-co-glycolic acid) (PLGA) carriers for inhalation. It presents the rational of use,thepotentialandtherecentadvancesindevelopingPLGAmicroparticlesand nanoparticles for pulmonary delivery. The most promising particle engineering strategiesarediscussed,highlightingtheadvantagesalongwiththemajorchallenges for researchers working in thisfield. Key findings Biodegradable polymer carriers, such as PLGA particles, may permit effective protection and long-term delivery of the inhaled drug and, when adequately engineered, its efficient transport to the target. The carrier can be designed for inhalation on the basis of several strategies through the adequate combinationof availableparticletechnologiesandexcipients.Insodoing,theproperties of PLGA particles can befinely tuned at micro-size and nano-size level to fulfill specific therapeutic needs. This means not only to realize optimal in vitro/in vivo lung depositionof theformulation,whichisstillcrucial,butalsotocontrolthefateof the drug in the lung after particle landing. Summary Although many challenges still exist, PLGA carriers may be highly beneficial and present a new scenario for patients suffering from chronic lung diseases and for pharmaceutical companies working to develop novel inhaled products.

Everted gut sac model as a tool in pharmaceutical research: limitations and applications

Abstract: Objectives This review discusses the limitations and applications of the everted gut sac model in studying drug absorption, metabolism, and interaction. Key findings The mechanism of drug absorption, interaction and the effect of factors such as age, sex, species, chronic therapy, and disease state on drug absorption have been summarized. The experimental conditions and their effects on the outcomes of trials have been discussed also. Summary The everted sac model is an efficient tool for studying in-vitro drug absorption mechanisms, intestinal metabolism of drugs, role of transporter in drug absorption, and for investigating the role of intestinal enzymes during drug transport through the intestine.

Overcoming sink limitations in dissolution testing: a review of traditional methods and the potential utility of biphasic systems.

Abstract: Objectives The conventional dissolution test, particularly the USP apparatus I and II, remains an important tool in the armory of the pharmaceutical development scientist. For realistic dissolution characterization, sink conditions, where saturation solubility of a drug in the dissolution medium is at least three times more than the drug concentration, are critical. These conditions can be problematic to maintain with formulations containing poorly-soluble actives. This review summarizes the role of the dissolution test in the pharmaceutical industry, together with some traditional techniques/additives used to enhance solubility and facilitate the achievement of sink conditions. The biphasic dissolution system, an innovative model for the treatment of poorly-soluble species, will also be discussed. Key findings The biphasic dissolution model utilizes media comprising immiscible aqueous and organic layers whereby the drug, following initial aqueous dissolution, partitions into the organic layer. This step, which acts to remove all dissolved species from the aqueous layer, enables further aqueous dissolution to occur and hence the dissolution-partition cycle continues. Crucially, the aqueous layer does not saturate allowing sink conditions to be maintained and hence the experiment will, in theory, yield complete dissolution. © 2012 The Authors. JPP © 2012 Royal Pharmaceutical Society.

Clove and eugenol in noncytotoxic concentrations exert immunomodulatory/anti-inflammatory action on cytokine production by murine macrophages.

Abstract: Objectives The extract and essential oil of clove (Syzygium aromaticum) are widely used because of their medicinal properties. Eugenol is the most important component of clove, showing several biological properties. Herein we have analysed the immunomodulatory/anti-inflammatory effect of clove and eugenol on cytokine production (interleukin (IL)-1β, IL-6 and IL-10) in vitro. Methods Macrophages were incubated with clove or eugenol (5, 10, 25, 50 or 100 µg/well) for 24 h. Concentrations that inhibited the production of cytokines were used before or after incubation with lipopolysaccharide (LPS), to verify a preventive or therapeutic effect. Culture supernatants were harvested for measurement of cytokines by enzyme-linked immunosorbent assay. Key findings Clove (100 µg/well) inhibited IL-1β, IL-6 and IL-10 production and exerted an efficient action either before or after LPS challenge for all cytokines. Eugenol did not affect IL-1β production but inhibited IL-6 and IL-10 production. The action of eugenol (50 or 100 µg/well) on IL-6 production prevented efficiently effects of LPS either before or after its addition, whereas on IL-10 production it counteracted significantly LPS action when added after LPS incubation. Conclusions Clove exerted immunomodulatory/anti-inflammatory effects by inhibiting LPS action. A possible mechanism of action probably involved the suppression of the nuclear factor-κB pathway by eugenol, since it was the major compound found in clove extract.

Comparative study of liposomes, transfersomes, ethosomes and cubosomes for transcutaneous immunisation: characterisation and in vitro skin penetration

Abstract: Objectives Lipid colloidal vaccines, including liposomes, transfersomes, ethosomes and cubosomes, were formulated, characterised and investigated for their ability to enhance penetration of a peptide vaccine through stillborn piglet skin in vitro. Methods Liposomes and transfersomes were formulated using a film-hydration method, ethosomes using a modified reverse phase method and cubosomes using a lipid precursor method. The size, zeta potential, peptide loading and interfacial behaviour of the formulations were characterised. Skin penetration studies were performed using Franz diffusion cells with piglet skin as the membrane. The localization of peptide in the skin was examined using confocal laser scanning microscopy. Key finding The various formulations contained negatively charged particles of similar size (range: 134–200 nm). Addition of the saponin adjuvant Quil A to the formulations destabilised the monolayers and reduced peptide loading. Cubosomes and ethosomes showed superior skin retention compared with the other systems. Confocal laser scanning microscopy showed greater peptide penetration and accumulation in the skin treated with cubosomes and ethosomes. With the other systems peptide was only located in the vicinity of the hair follicles and within the hair shaft. Conclusions We conclude from the in-vitro studies that cubosomes and ethosomes are promising lipid carriers for transcutaneous immunisation.

Accelerated in-vitro release testing methods for extended-release parenteral dosage forms.

Abstract: Objectives This review highlights current methods and strategies for accelerated in-vitro drug release testing of extended-release parenteral dosage forms such as polymeric microparticulate systems, lipid microparticulate systems, in-situ depot-forming systems and implants. Key findings Extended-release parenteral dosage forms are typically designed to maintain the effective drug concentration over periods of weeks, months or even years. Consequently, ‘real-time’ in-vitro release tests for these dosage forms are often run over a long time period. Accelerated in-vitro release methods can provide rapid evaluation and therefore are desirable for quality control purposes. To this end, different accelerated in-vitro release methods using United States Pharmacopeia (USP) apparatus have been developed. Different mechanisms of accelerating drug release from extended-release parenteral dosage forms, along with the accelerated in-vitro release testing methods currently employed are discussed. Summary Accelerated in-vitro release testing methods with good discriminatory ability are critical for quality control of extended-release parenteral products. Methods that can be used in the development of in-vitro–in-vivo correlation (IVIVC) are desirable; however, for complex parenteral products this may not always be achievable.

Nephroprotective efficacy of chrysin against cisplatin-induced toxicity via attenuation of oxidative stress.

Abstract: Objectives Cisplatin-induced nephrotoxicity is the main cause for its dose-limited use in the treatment of various cancers and results in acute renal cell injury through generation of reactive oxygen species Chrysin possess antioxidant, anti-inflammatory and anti-cancer properties The aim of this study was to investigate the protective efficacy of chrysin against cisplatin-induced nephrotoxicity Methods Thirty male Wistar rats were divided into five groups with six rats in each group Group I served as control and received corn oil (vehicle of chrysin) for 14 days and 09% saline (vehicle of cisplatin) on day 14 only Group II received a single intraperitoneal injection of cisplatin on day 14 Group III and IV were pretreated with two different doses of chrysin in addition to cisplatin and group V received chrysin only Rats were examined for the effect of chrysin on cisplatin induced depletion of antioxidant enzymes, induction of lipid peroxidation and DNA damage in the kidney, utilizing a well-established model of cisplatin-induced nephropathy Key findings Pretreatment with chrysin significantly attenuated cisplatin-induced renal oxidative damage by diminishing the DNA damage and toxicity markers, such as creatinine and blood urea nitrogen, lipid peroxidation and xanthine oxidase activity, accompanied by increase in enzymatic (catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase) and non-enzymatic (reduced glutathione) antioxidant status Histological findings further substantiated the protective efficacy of chrysin, which reduced cisplatin-induced renal damage Conclusions The data of the present study suggest that chrysin effectively suppress cisplatin-induced renal injury by ameliorating oxidative stress

The inhibition of catecholamine biosynthesis by apomorphine

Abstract: Apomorphine stimulates the dopamine receptors in the striatum (Ernst, 1967; Ernst & Smelik, 1966; AndCn, Rubenson & others, 1967). More recently, apomorphine was also used in the treatment of parkinsonism (Cotzias, Papavasiliou & others, 1970). Biochemical studies have shown that apomorphine retards the depletion of the central dopamine stores, but not noradrenaline stores, in animals pretreated with tyrosine hydroxylase inhibitors (AndCn & others, 1967). Apomorphine reduces the impulse flow of the dopamine neurons, probably by a negative feedback mechanism arising from dopamine receptor stimulation. But no evidence exists on whether apomorphine has a direct effect on tyrosine hydroxylase activity. Apomorphine contains a catecho1 group and catechols are known to be inhibitors of tyrosine hydroxylase (Nagatsu, Levitt & Udenfriend 1964; Goldstein, Gang & Anagoste, 1967). We have now investigated the effects of apomorphine on tyrosine hydroxylase activity and on dopamine biosynthesis in vitro and in vivo. Male Sprague-Dawley rats, 250-300 g, were decapitated and the striata immediately dissected, sliced and incubated at 37\" in Krebs-Henseleit medium. The incubation procedure and the determination of [14C]catecholamines was done as previously described (Goldstein, Ohi & Backstrom, 1970). In some experiments the animals were treated with apomorphine 25 mg/kg subcutaneously and 30 min later [14C]~-tyrosine (U) (6.25 @/rat ; specific activity 450 mCi/mol) was administered intracisternally. Haloperidol (2mg/kg, i.p.) was given 30 min before the apomorphine. Tyrosine hydroxylase activity was measured according to Nagatsu & others (1964). The effects of apomorphine on tyrosine hydroxylase activity at different concentrations of the substrate 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine (DMPH,) are in Table 1. Apomorphine 10\"'~ significantly inhibits tyrosine hydroxylase activity. At lower concentrations of the pteridine the inhibition by apomorphine is more effective. However, at 10-6~, apomorphine does not inhibit significantly tyrosine hydrolyase activity even at low DMPH, concentrations. Apomorphine inhibits effectively the biosynthesis of [14C]dopamine from [14C] tyrosine in slices of rat striatum (Table 2) even at and ~O-'M. Thus, striatal slices are more sensitive to the inhibition of [14C]dopamine biosynthesis by apomorphine than tyrosine hydroxylase preparations obtained either from bovine adrenal glands or from the striatum of rats. The addition of haloperidol to the media in which the striatal slices were incubated did not affect the inhibitory activity of apomorphine. In separate experiments the effects of apomorphine on [14C]catecholamines were investigated after intraventricular injection of [14C]tyrosine. Treatment with apomor-

Berberine suppresses amyloid-beta-induced inflammatory response in microglia by inhibiting nuclear factor-kappaB and mitogen-activated protein kinase signalling pathways

Abstract: Objectives The neuroinflammation induced by amyloid-beta peptide (Aβ) is one of the key events in Alzheimer's disease (AD) progress in which microglia are the main cells involved. Berberine, one of the major constituents of Chinese herb Rhizoma coptidis, is known for its anti-inflammatory, anti-oxidative and anti-microbial activity. In this study, we examined the effects and possible underlying mechanisms of berberine in Aβ-induced neuroinflammation using murine primary microglia cells and cultured BV2 microglia cells. Methods The effects of berberine on Aβ-stimulated inflammatory factor expression and secretion were examined using RT-PCR and ELISA analysis. The signal pathways involved in berberine's effects were also investigated using Western blot and immunofluorescence analysis. Results In primary microglial and BV2 cells, berberine treatment significantly inhibited Aβ-stimulated production of interleukin-6 and monocyte chemotactic protein-1. Berberine treatment down-regulated the expression of cyclo-oxygenase-2 and induced nitric oxide synthase in these cells. Moreover, berberine strongly inhibited the nuclear factor-kappaB (NF-κB) activation, presumably through blocking the phosphoinositide 3-kinase/protein kinase B and mitogen-activated protein kinase signalling pathways. Conclusions Our data indicated berberine is a potent suppressor of neuroflammation, presumably through inhibition of NF-κB activation, and suggested berberine has therapeutic potential for the treatment of neuroinflammation that is involved in neurological diseases such as AD.

Hesperidin-mediated expression of Nrf2 and upregulation of antioxidant status in senescent rat heart

Abstract: Objectives Oxidative stress is recognized as a key element responsible for the development of age-related pathologies A declining endogenous defence system during senescence dictates the need for supplementation with exogenous antioxidants through diet Hesperidin is a naturally occurring flavonone present in citrus fruits and has been shown to have many biological properties, including antioxidant activity We investigated whether hesperidin supplementation could be valuable in protecting cardiac tissue of aged rats against age-related increase in oxidative stress, as well as the mechanism by which it can boost the antioxidant status of the cell Methods The activity of antioxidant enzymes, mRNA expression of Nrf2, protein levels of superoxide dismutase and catalase were measured using standard protocols Key findings Hesperidin treatment effectively protected aged rat heart by increasing the activity of enzymic antioxidants Hesperidin upregulated the protein levels of nuclear factor erythroid 2-related factor 2, which is responsible for maintaining the antioxidant status of the cell Conclusions Hesperidin could be useful in protecting cardiomyocytes against age-related increase in oxidative stress mediated by Nrf2 upregulation

Intranasal delivery of insulin via the olfactory nerve pathway.

Abstract: Objectives Intranasal delivery has been shown to target peptide therapeutics to the central nervous system (CNS) of animal models and induce specific neurological responses.In an investigation into the pathways by which intranasal administration delivers insulin to the CNS, this study has focused on the direct delivery of insulin from the olfactory mucosa to the olfactory bulbs via the olfactory nerve pathway. Methods Nasalandolfactorytissuesof micewereimagedwithfluorescentandelectron microscopy 30 min following intranasal administration. Keyfindings Macroscopicanalysisconfirmeddeliverytotheanteriorregionsof the olfactory bulbs. Confocal microscopy captured delivery along the olfactory nerve bundles exiting the nasal mucosa, traversing the cribriform plate and entering the bulbs. With electron microscopy, insulin was found within cells of the olfactory nerve layer and glomerular layer of the olfactory bulbs. Conclusions Theseresultsdemonstratedthatintranasaladministrationof labelled insulin targeted the CNS through the olfactory nerve pathway in mice.

Role of Bcl‐2 in tumour cell survival and implications for pharmacotherapy

Abstract: Bcl-2 is a protein that inhibits apoptosis, leading to cell survival. The Bcl-2 family has six different anti-apoptotic proteins, three pro-apoptotic proteins that are similar in structure, and other integrating proteins that function as promotors or inhibitors in the progression of apoptosis. In this discussion paper, we provide an overview of apoptosis, the role of Bcl-2 in normal cellular and molecular processes, and the role of Bcl-2 in tumour cell survival. It focuses primarily on anti-apoptotic Bcl-2, its activation in cancer, the manner in which it regulates the intrinsic and extrinsic mechanisms of apoptosis, and its broad molecular interactions with other critical proteins in the cell. Certain cancer treatments are reviewed and related directions for the future are presented.

Antinociceptive activity of carvacrol (5-isopropyl-2-methylphenol) in mice.

Abstract: Objectives Carvacrol (5-isopropyl-2-methylphenol) is a monoterpenic phenol which is present in the essential oil of oregano and thyme.We have investigated the behavioural effects of carvacrol in animal models of pain, such as acetic acidinduced abdominal constriction, formalin and hot-plate tests in mice. The spontaneous motor activity of animals treated with carvacrol was investigated using open-field and rotarod tests. Methods Carvacrol was administered orally, at single doses of 50 and 100 mg/kg whileindometacin(5 mg/kg),morphine(7.5 mg/kg)anddiazepam(2 mg/kg)were used as standard drugs.Naloxone (1 mg/kg) and l-arginine (150 mg/kg) were used to elucidate the possible antinociceptive mechanism of carvacrol on acetic acidinduced abdominal constriction and formalin tests. Keyfindings Theresultsshowedthatcarvacrolproducedsignificantinhibitionson nociception in the acetic acid-induced abdominal constriction, formalin and hotplate tests.In the open-field and rotarod tests carvacrol did not significantly impair the motor performance. The effect of the highest dose of carvacrol in mice in the acetic acid-induced abdominal constriction and formalin tests were not reversed by naloxone orl-arginine. Conclusions Based on these results, it has been suggested that carvacrol presents antinociceptive activity that may not act through the opioid system nor through inhibition of the nitric oxide pathway.

Inhibitory effects of Zataria multiflora essential oil and its main components on nitric oxide and hydrogen peroxide production in lipopolysaccharide-stimulated macrophages.

Abstract: Objectives Zataria multiflora is an aromatic plant that is used in flavouring and preserving foods and also used as an antispasmodic, anaesthetic and antinociceptive agent. In this study, the effects of Z. multiflora essential oil on nitric oxide (NO) and hydrogen peroxide (H2O2) production in lipopolysaccharide (LPS)-stimulated macrophages was investigated. Methods Z. multiflora essential oil was extracted by water-distillation, analysed by GC-MS and then the effect of the essential oil on NO and H2O2 production was investigated. Key findings Carvacrol (52%), thymol (16%) and p-cymene (10%) were the main components of the oil. The IC50 (concentration providing 50% inhibition) for reactive oxygen scavenging was estimated to be 5.7, 3 and 4.2 µg/ml for the essential oil, thymol and carvacrol, respectively, while the corresponding IC50 values for reactive nitrogen scavenging were estimated to be 8.6, 4.7 and 6.6 µg/ml. Z. multiflora essential oil, thymol, and carvacrol significantly reduced NO and H2O2 production as well as NO synthase and NADH oxidase activity in LPS-stimulated murine macrophages while p-cymene did not show any antioxidant activity. Conclusions Z. multiflora essential oil has the potential to be used in the therapy of oxidative damage.

Dissolution testing of oral modified-release dosage forms

Abstract: Objectives The in-vivo performance of oral modified-release dosage forms is determined by the interplay of various physiological- and dosage-form-derived parameters. Thus it is often a challenge to predict the in-vivo drug-release behaviour from modified-release dosage forms based solely on in-vitro release rates. Key findings For a long time the most common procedure to obtain in-vitro/in-vivo correlations for modified-release formulations was to apply test conditions typically used for quality control on a retrospective basis. Such so-called ‘compendial approaches’ are typically not biorelevant with respect to volumes, composition and physicochemical properties of the test media and also do not take into consideration the mechanical and hydrodynamic forces that may influence dosage-form behaviour during passage through the gastrointestinal tract. Summary This review provides an overview of physiological conditions relevant to in-vivo drug release and of dissolution models which, based on current scientific findings on human gastrointestinal physiology, have been developed to enable a better prediction of the in-vivo performance of oral MR dosage forms.

Role of fetuin-A in atherosclerosis associated with diabetic patients.

Abstract: Objectives Fetuin-A is a circulating glycoprotein, formed in the liver. It regulates bone remodelling and calcium metabolism. Fetuin-A has adipogenic properties, so fat accumulation in the liver may be associated with higher levels of fetuin-A. Fetuin-A is an inhibitor of the phosphorylation of the insulin receptor tyrosine kinase. Key findings High concentrations of fetuin-A in humans causes insulin resistance. Insulin sensitivity is also found to be increased in fetuin-A knockout mice. Fetuin-A has been shown to cause insulin resistivity in type-2 diabetes mellitus and worsens the pro-atherogenic milieu. Summary Fetuin-A should be considered as a hepatic bio-marker. Vascular diseases like atherosclerosis are major causes of disability in patients with diabetes mellitus.

Antinociceptive activity of the monoterpene α-phellandrene in rodents: possible mechanisms of action.

Abstract: Objectives The aim of this work was to investigate the antinociceptive property of α-phellandrene (α-PHE) in experimental nociception models and possible mechanisms involved. Methods Mass spectrometry was used to evaluate the purity and molecular mass of α-PHE. Macrophages from mice peritoneal cavity were used in an MTT test. Rodents were used in tests of chemical and mechanical nociception. In the study of the mechanisms, the animals were treated with pharmacological tools and then submitted to the glutamate test. Key findings α-PHE purity was 98.2% and molecular mass 136.1 Da. α-PHE did not show cytotoxicity. In the writhing and capsaicin tests, α-PHE promoted the antinociceptive effect in all evaluated doses (minimum dose 3.125 mg/kg). In the formalin test, α-PHE (50 mg/kg) was effective in inhibiting both phases. In the glutamate test, the monoterpene (12.5 mg/kg) decreased the nociceptive response. In carrageenan-induced hyperalgesia, α-PHE (50 mg/kg) decreased the hypernociception index. In the study of the mechanisms involved, pretreatment with naloxone reversed the α-PHE antinociceptive effect, the same occurred with glibenclamide, l-arginine, atropine and yohimbine. α-PHE did not show muscle relaxant activity or central depressant effects in open field and rota rod tests. Conclusions α-PHE has an antinociceptive effect and it possibly involves the glutamatergic, opioid, nitrergic, cholinergic and adrenergic systems.

Condensational growth of combination drug-excipient submicrometer particles for targeted high-efficiency pulmonary delivery: evaluation of formulation and delivery device

Abstract: Objectives The objective of this study was to investigate the in vitro particle size growth of combination drug and excipient submicrometer aerosols generated from a series of formulations and two aerosol delivery devices.

Mucus thickness in the gastrointestinal tract of laboratory animals

Abstract: Objectives The objective of this study was to systematically assess the mucus thickness in the gastrointestinal tract of laboratory animals commonly used in preclinical studies. Methods Mucus thickness was studied post-mortem in the rat, rabbit and pig, using cryosections stained by the modified periodic acid Schiff/Alcian blue method. Key findings The mucus thickness in the fundus region of the stomach was higher in the pig (190.7 ± 80.7 µm) than in the rabbit (155.1 ± 85.8 µm) and the rat (31.3 ± 11.4 µm). However, along the small intestine (ileum), mucus was thicker in the rabbit (147.8 ± 115.6 µm), followed by the pig (53.8 ± 22.1 µm) and the rat (34.1 ± 14.9 µm). This rank order was also observed in the ascending colon. Conclusions Inter-species variability in mucus thickness along the gut was demonstrated and suggests that the pig resembles more closely the mucus pattern of humans. This may be highly relevant when preclinical animal models are used in drug absorption studies or in the development of oral mucoadhesive drug delivery systems.

Dissolution testing of orally disintegrating tablets.

Abstract: For industrially manufactured pharmaceutical dosage forms, product quality tests and performance tests are required to ascertain the quality of the final product. Current compendial requirements specify a disintegration and/or a dissolution test to check the quality of oral solid dosage forms. These requirements led to a number of compendial monographs for individual products and, at times, the results obtained may not be reflective of the dosage form performance. Although a general product performance test is desirable for orally disintegrating tablets (ODTs), the complexity of the release controlling mechanisms and short time-frame of release make such tests difficult to establish. For conventional oral solid dosage forms (COSDFs), disintegration is often considered to be the prerequisite for subsequent dissolution. Hence, disintegration testing is usually insufficient to judge product performance of COSDFs. Given the very fast disintegration of ODTs, the relationship between disintegration and dissolution is worthy of closer scrutiny. This article reviews the current status of dissolution testing of ODTs to establish the product quality standards. Based on experimental results, it appears that it may be feasible to rely on the dissolution test without a need for disintegration studies for selected ODTs on the market.

Reversal of P‐glycoprotein‐mediated multidrug resistance of human hepatic cancer cells by Astragaloside II

Abstract: Objectives Chemoresistance is the main obstacle encountered in cancer treatment and is frequently associated with multidrug resistance (MDR). Astragaloside is a saponin which is widely used in traditional Chinese medicine. It has been reported that Astragaloside has antitumour effects on hepatocellular carcinoma Bel-7402 cells in vitro and in vivo. The purpose of this study was to examine the effects of Astragaloside II on the reversal of MDR and its molecular mechanism in vitro. Methods In this study, Bel-7402 and Bel-7402/FU cell lines were used as the experimental model. Drug sensitivity was determined using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, accumulation and efflux of Rh123 were analyzed by flow cytometer, the mRNA level of mdr1 was determined by RT-PCR and the protein levels of P-glycoprotein (P-gp) and mitogen-activated protein kinase were determined by Western blot. Key findings Astragaloside II (0.08 mg/ml) showed strong potency to increase 5-fluorouracil cytotoxicity toward 5-fluorouracil-resistant human hepatic cancer cells Bel-7402/FU. The mechanism of Astragaloside II on P-gp-mediated MDR demonstrated that Astragaloside II significantly increased the intracellular accumulation of rhodamine 123 via inhibition of P-gp transport function. Based on the analysis of P-gp and mdr1 gene expression using Western blot and RT-PCR, the results revealed that Astragaloside II could downregulate the expression of the P-gp and mdr1 gene. In addition, Astragaloside II suppressed phosphorylation of extracellular signal regulated kinase 1/2, p38 and c-Jun N-terminal kinase. Conclusions The results suggested that Astragaloside II is a potent MDR reversal agent and may be a potential adjunctive agent for hepatic cancer chemotherapy.

Therapeutic properties of quercetin on monosodium urate crystal-induced inflammation in rat

Abstract: Objectives Gouty arthritis is characterized by intense, acute inflammatory reactions that occur in response to articular deposits of monosodium urate crystals. In this study we have assessed the effects of the flavonoid, quercetin, on monosodium urate crystal-induced inflammation in rats, an experimental model for gouty arthritis. Methods Gouty arthritis was induced by intra-articular injection of monosodium urate crystal suspension inside the ankle joint of the rat right hind limb. Circumference was assessed at 2, 4, 8, 12, 24, and 48 h after monosodium urate crystal injection. Histopathological analysis of joint synovial tissue, inflammatory mediator levels, lipid peroxidation, and antioxidant status in serum, liver and joint synovial tissue were determined in control and monosodium urate crystal-treated rats at the end of experiment. Key findings Quercetin treatment attenuated oedema in a dose-dependent manner and decreased histological signs of acute inflammation in the treated animals. In addition, quercetin treatment suppressed leucocyte recruitment, decreased chemokine levels, decreased levels of the lipid peroxidation end-product malondialdehyde, and increased antioxidant enzyme activity in treated rats. Conclusions These results indicated that quercetin exerted a strong anti-inflammatory effect that may be useful for the treatment of acute gouty arthritis.

Anti-tumour effects of elatol, a marine derivative compound obtained from red algae Laurencia microcladia.

Abstract: Objectives This paper aims to evaluate the anti-tumour properties of elatol, a compound (sesquiterpene) isolated from algae Laurencia microcladia. Methods In-vitro and in-vivo anti-tumour properties of elatol were investigated using: MTT assays to assess the cytotoxic effects; flow cytometry analysis to examine the cell cycle and apoptosis; Western blot analysis for determination of the expression of cell cycle and apoptosis proteins; and study of in-vivo tumour growth in mice (C57Bl6 mice bearing B16F10 cells). Key findings Elatol exhibited a cytotoxic effect, at least in part, by inducing cell cycle arrest in the G1 and the sub-G1 phases, leading cells to apoptosis. Western blot analysis demonstrated that elatol reduced the expression of cyclin-D1, cyclin-E, cyclin-dependent kinase (cdk)2 and cdk4. A decrease in bcl-xl and an increase in bak, caspase-9 and p53 expression was also observed. In the in-vivo experiment, treatment with elatol was able to reduce tumour growth in C57Bl6 mice. Conclusions Elatol promotes a delay in the cell cycle, probably in the G1/S transition, activating the apoptotic process and this could be responsible, at least in part, for the in-vivo effects observed. Taken together, the in-vitro and in-vivo experiments suggested that elatol has anti-tumour properties. Further studies should be conducted to clarify the mechanism of action.

Osteoarthritis of the knee and hip. Part I: aetiology and pathogenesis as a basis for pharmacotherapy.

Abstract: Objectives: Osteoarthritis (OA) of the knee and hip is among the most frequent and debilitating arthritic conditions. Aside from surgical intervention in severe cases, conventional treatment involves relieving painful symptoms with non-steroidal anti-inflammatory drugs (NSAIDs), narcotic and non-narcotic (weak) analgesics and physical therapy. To obtain insight into the extent of pathological changes in hip and knee OA we reviewed current literature on the pathogenesis of this state as a basis for current pharmacotherapy options. Key findings: Key features of the pathological joint changes in OA include: cartilage destruction by pro-inflammatory cytokines, matrix metalloproteinases and prostaglandins, which promote a catabolic environment; subchondral bone remodelling and resorption; hypertrophic differentiation of chondrocytes; neovascularisation of synovial tissue; and focal calcification of joint cartilage. Despite the central involvement of hyaline cartilage in OA pathogenesis, the source of pain likely stems from the richly innervated synovium, subchondral bone and periosteum components of the joint. Tissue damage during joint degeneration generates nociceptive stimuli. The presence of inflammatory mediators, including bradykinin, prostaglandins and leukotrienes, lowers the threshold of the Aδ and C pain fibres, resulting in a heightened response to painful stimuli. Summary: It is our opinion that it is important to base and centre the management of OA patients on the severity of patient-important outcomes, rather than purely an assessment of damage to the joint. The joint damage, as interpreted from radiographs, is not necessarily representative of the symptoms experienced. The management of OA primarily comprises pharmacological therapy, surgical interventions and various non-pharmacological interventions.

Cultivation of RPMI 2650 cells as an in-vitro model for human transmucosal nasal drug absorption studies: optimization of selected culture conditions

Abstract: Objectives The kinetics of drug absorption for nasally administered drugs are often studied using excised mucosal tissue. To avoid the disadvantages of animal experiments, cellular in-vitro models have been established. This study describes the optimization of culture conditions for a model based on the RPMI 2650 cell line, and an evaluation of this model's value for drug absorption studies. Methods The cells were cultured in two serum-free media, serum-reduced variants or minimum essential medium (MEM) containing 5–20% serum. Cell seeding efficiency and proliferation behavior were evaluated in addition to viability and attachment following cryopreservation and thawing. Cells were cultured on different filter inserts for varying cultivation times. The epithelial barrier properties were determined by measuring transepithelial electrical resistance (TEER). Permeability was assessed using marker substances. Key findings Serum supplementation of medium was necessary for cultivation, whereas the serum concentration showed little impact on proliferation and attachment following cryopreservation. A pronounced dependence of TEER on medium and filter material was observed. An optimized model cultured with MEM containing 10% serum on polyethylene terephthalate exhibited permeability that was similar to excised nasal mucosa. Conclusions These data indicate that this model could be an appropriate alternative to excised mucosa for the in-vitro evaluation of nasal drug absorption.

A mechanistic pharmacokinetic model to assess modified oral drug bioavailability post bariatric surgery in morbidly obese patients: interplay between CYP3A gut wall metabolism, permeability and dissolution.

Abstract: Objectives Due to the multi-factorial physiological implications of bariatric surgery, attempts to explain trends in oral bioavailability following bariatric surgery using singular attributes of drugs or simplified categorisations such as the biopharmaceutics classification system have been unsuccessful. So we have attempted to use mechanistic models to assess changes to bioavailability of model drugs. Methods Pharmacokinetic post bariatric surgery models were created for Roux-en-Y gastric bypass, biliopancreatic diversion with duodenal switch, sleeve gastrectomy and jejunoileal bypass, through altering the ‘Advanced Dissolution Absorption and Metabolism’ (ADAM) model incorporated into the Simcyp® Simulator. Post to pre surgical simulations were carried out for five drugs with varying characteristics regarding their gut wall metabolism, dissolution and permeability (simvastatin, omeprazole, diclofenac, fluconazole and ciprofloxacin). Key findings The trends in oral bioavailability pre to post surgery were found to be dependent on a combination of drug parameters, including solubility, permeability and gastrointestinal metabolism as well as the surgical procedure carried out. Conclusions In the absence of clinical studies, the ability to project the direction and the magnitude of changes in bioavailability of drug therapy, using evidence-based mechanistic pharmacokinetic in silico models would be of significant value in guiding prescribers to make the necessary adjustments to dosage regimens for an increasing population of patients who are undergoing bariatric surgery.

Understanding the molecular pharmacology of the serotonergic system: using fluoxetine as a model

Abstract: Objectives Serotonin is a monoamine neurotransmitter that is widely distributed in the body and plays an important role in a variety of psychological and other body functions such as mood, sexual desire and function, appetite, sleep, memory and learning, temperature regulation and social behaviour. This review will assess the use of fluoxetine, one of the most commonly used selective serotonin reuptake inhibitors, as a model for understanding the molecular pharmacology of the serotoninergic system. Key findings Seven serotonin receptor families have been discovered to date. All serotonin receptors, except 5-HT3, are G-protein coupled, seven transmembrane receptors that activate an intracellular second messenger cascade. The 5-HT3 receptor is a ligand-gated ion channel. Furthermore, 5-HT1A receptors are known as autoreceptors since their stimulation inhibits the release serotonin in nerve terminals. A transporter protein found in the plasma membrane of serotonergic neurones is responsible for the reuptake of this neurotransmitter. Selective serotonin reuptake inhibitors, such as fluoxetine, act primarily at the serotonin transporter protein and have limited, if any, reaction with other neurotransmitter systems. Selective serotonin reuptake inhibitors appear to bind with the serotonin transporter with different rates of occupancy, duration and potency. Summary The following review focuses on the interaction of serotonin with this membrane transporter in the body and assesses the use of fluoxetine as a reference drug in the understanding of this interaction.

Anti-depressant effects of Xiaoyaosan on rat model of chronic unpredictable mild stress: a plasma metabonomics study based on NMR spectroscopy

Abstract: Objectives To investigate the antidepressant effects of Xiaoyaosan (XYS) in a chronic unpredictable mild stress (CUMS) depression model. Methods The changes in behaviour and plasma metabolic profiles were investigated after four-week CUMS exposure and treatment. Drugs were administered during the four-week period of CUMS, with the healthy group serving as negative controls, and the fluoxetine and venlafaxine groups serving as positive controls. Plasma samples were collected at 28th day, and the plasma metabolic profiling was measured using NMR, followed by multivariate analysis. Key findings Exposure to CUMS for four weeks caused depression-like behaviour in rats, as indicated by significant decreases in weight gain, sucrose consumption and locomotor activity. Eleven potential biomarkers, including seven in the Carr–Purcell–Meiboom–Gill spectra, five in the diffusion-edited spectra, and one in both were identified. It was found that trimethylamine-N-oxide, alanine, β-hydroxybutyrate, valine, leucine/isoleucine, low-density lipoprotein/very low-density lipoprotein and lipids were lower and phosphatidylcholine, high-density lipoprotein, choline and N-acetyl glycoproteins were higher in CUMS-treated rats, as compared with controls. XYS significantly suppressed behavioural changes and attenuated plasma metabolite changes. Conclusions XYS produced an obvious antidepressant effect, and the metabonomic approach benefits estimation of the pharmacodynamic action of traditional Chinese medicine prescriptions.