Effect of γ-cyclodextrin on the in vitro skin permeation of a steroidal drug from nanoemulsions: impact of experimental setup

Numerous reports on the enhancement effect of cyclodextrins (CDs) on the skin permeation of dermally applied drugs exist, the majority of which is based on in vitro diffusion cell studies. The specific experimental setup of such studies may skew the obtained results, which is rarely discussed in the context of CD studies. Thus, the aim of this work was to conduct a systematic in vitro investigation of the permeation enhancement potential of γ-CD on a steroidal drug from a nanoemulsion. The role of critical diffusion cell parameters such as the dose of application, occlusive conditions, the nature of the receptor medium and the skin thickness were investigated. The results showed that significantly enhanced skin permeation rates of fludrocortisone acetate were indeed caused by 1% (w/w) of γ-CD at both finite and infinite dose conditions. At 0.5% (w/w) of γ-CD, significant enhancement was only achieved at infinite dose application. Additional in vitro tape stripping experiments confirmed these tendencies, but the observed effects did not reach statistical significance. It may be concluded that the full permeation enhancement potential of the CD as observed in the franz-cell setup can only be realised at infinite dose conditions while preserving the formulation structure.     

A comparative trial of a new,fast-release iron capsule (‘Eryfer’) and a slow-release tablet (‘Ferro-Gradumet’) in iron-deficiency anaemia

Summary

Sixty hospitalised patients receiving treatment for tuberculosis, diabetes or chronic bronchitis and who had iron-deficiency anaemia (Hb levels less than 12.5g.ll00 ml.) were entered in a between-patient comparative study of a new, fast-release iron capsule (‘Eryfer’) and a standard slow-release iron tablet (‘Ferro-Gradumet’).

Patients were allocated to either drug at random and received either 2 capsules (100?mg. elemental iron) or 1 tablet (105?mg. elemental iron) daily for 30 days. Haemoglobin levels and packed cell volume were measured before and at the end of the trial period. The results, analysed in 57 patients (28 on ‘Eryfer’ and 29 on the slow-release iron) indicate that treatment with ‘Eryfer’ produced a significantly more predictable response in haemoglobin regeneration, the response being dependent on the initial haemoglobin level. Both treatments, however, produced a highly significant increase in haemoglobin levels in the patients (mean increase: ‘Eryfer’ 1.09?g. and slow-release iron 0.76?g.). No side-effects were recorded with either treatment.     

Effect of calculation stress on hemodynamics and plasma catecholamines before and afterβ-blockade with propranolol (inderal®) and mepindolol sulfate (CORINDOLAN®)

Summary The effect of calculation stress on hemodynamic parameters and plasma adrenalin and noradrenalin was studied in two groups of 6 male subjects, before and during-Blockade. One group received propranolol 15 mg i. v. and the other received mepindolol sulphate 0,5 mg i. v. There was an increase in heart rate, cardiac output and blood pressure during mental stress. A significant increase in plasma adrenalin but not in noradrenalin occurred at the same time. The stress-induced rise in HR but not that in blood pressure could be prevented by-receptor blockade with proprandolol and mepindolol sulfate. The peripheral resistance (PR) and diastolic blood pressure in stress were even higher after propranolol than in the control study. Propranolol had no effect on the increased adrenalin concentration during stress, but it was prevented by mepindolol sulfate. There was no correlation between the increase in HR and that in adrenalin during stress, but the HR in stress and the HR reaction to infused isoproterenol were highly correlated.     

Evaluation of IgE Antibodies to Omalizumab (Xolair®) and Their Potential Correlation to Anaphylaxis

Omalizumab (Xolair®) is a recombinant humanized monoclonal antibody that selectively binds to human immunoglobulin E (IgE). Omalizumab is used to treat IgE-mediated diseases such as chronic idiopathic urticaria (CIU) and moderate to severe allergic asthma. In pre-marketing clinical trials in patients with asthma, anaphylaxis was reported in 3 of 3,507 (0.1%) patients. In post-marketing spontaneous reports, the frequency of anaphylaxis attributed to omalizumab use was estimated to be at least 0.2% of patients based on an estimated exposure of about 57,300 patients from June 2003 through December 2006. To better understand the risk of anaphylaxis in patients with allergic asthma receiving omalizumab, a post-marketing pharmacosurveillance study was initiated in 2009. As part of this study, an assay was developed to detect antibodies of IgE isotype to omalizumab. Serum samples from patients in the study were evaluated using this assay. Our results indicated that there was no observable correlation between either anaphylaxis or skin test reactivity and the presence of antibodies of IgE isotype to omalizumab. Here, we discuss the development of this assay as well as the results of the immunogenicity assessment.Key Words: biotin-mutant omalizumab-AAA, DIG-FcεR1-IgG, IgE isotype, omalizumab (Xolair®), omalizumab/total IgE molar ratio     

Effect of thermal processing and γ-irradiation on allergenicity of legume proteins

Legumes are implicated in IgE mediated food allergy in different countries. The present study aimed to investigate the effect of different processing methods on allergenicity of legume proteins. The extracts were processed by boiling, γ-irradiation or by combination of both. The changes in soluble protein content, specific IgE binding and allergenic potential of legume proteins were assessed. Thermal processing resulted in a 3- to 4-fold reduction in soluble protein. Specific IgE binding was reduced 74 ± 6.5%, 83 ± 11.6% and 62 ± 7.2% in the soluble protein of kidney bean, black gram and peanut, respectively, after boiling (p < 0.01) whereas there was 34 ± 5.2%, 74 ± 15.6% and 44 ± 11.1% IgE binding reduction in the insoluble protein fraction of respective legumes. Boiling followed by γ-irradiation reduced IgE binding significantly (p < 0.05). Biopotency of soluble protein of kidney bean, black gram and peanut was reduced 7-, 3- and 26-folds (p < 0.001), respectively, and that of insoluble protein decreased 6-, 4- and 8-folds (p < 0.001), respectively, after boiling. Combination treatment was effective in reducing the potency of both soluble and insoluble protein significantly as compared to boiling alone (p < 0.001). However, γ-irradiation alone did not bring any change in allergenicity. In conclusion, boiling followed by γ-irradiation is effective in attenuating allergenicity of legume proteins.     

Physical and enteric properties of soft gelatin capsules coated with eudragit ® L 30 D-55

The enteric coating of soft gelatin capsules (SGC) containing ibuprofen in either PEG 400 or Miglyol© was investigated. The effects of two plasticizers, triethyl citrate (TEC) and tributyl citrate (TBC), on the physical and enteric properties of SGC coated with Eudragit ® L 30 D-55 were studied. The water soluble plasticizer TEC was found to be a good plasticizing agent for the Eudragit® L 30 D-55 irrespective of the fill liquid, while the TBC provided satisfactory results only for capsules containing the hydrophobic fill liquid, Miglyol ®. The combination of TEC and TBC provided effective plasticization for the acrylic coating regardless of the fill liquid. A subcoat of HPMC showed no effect on the enteric protection of either Miglyol® - and PEG-containing capsules that were stored at room temperature and zero percent relative humidity. The moisture content of the gelatin shell of the film coated SGC stored at room temperature and at 0 or 96% relative humidity was followed as a function of time. The load strength of the capsules was measured during 3 months of storage using an Instron universal testing apparatus, and the physical-mechanical properties of the capsules were correlated with the moisture content of the SGC. As the moisture content of the gelatin decreased, all formulations exhibited an increase in load strength.     

Application of a Novel ‘Make and Test in Parallel’ Strategy to Investigate the Effect of Formulation on the Pharmacokinetics of GDC-0810 in Healthy Subjects

Purpose

GDC-0810, administered orally, was used in Phase I and II clinical studies to treat estrogen receptor positive breast cancers. It contains N-methyl-D-glucamine (NMG) salt of GDC-0810 with 10% sodium lauryl sulfate (SLS) as a surfactant and 15% sodium bicarbonate (NaHCO₃) as an alkalizing agent to aid dissolution. To improve the processability of the formulation and reduce potential mucosal irritation in future Phase III clinical studies, the salt form and the amount of excipient required further optimization. To achieve this, we employed a novel “Make and Test in Parallel” strategy that facilitated selecting formulation in a rapid timeframe.

Methods

RapidFACT®, a streamlined, data-driven drug product optimization platform was used to bridge Phase I/II and Phase III formulations of GDC-0810. Five prototype formulations, varying in either the form of active pharmaceutical ingredient and/or the levels of the excipients SLS and NaHCO₃ were assessed. Uniquely, the specific compositions of formulations manufactured and dosed were selected in real-time from emerging clinical data.

Results

The study successfully identified a Phase III formulation with a reduced SLS content, which when administered following a low-fat meal, gave comparable pharmacokinetic exposure to the Phase I/II formulation administered under the same conditions.

Conclusions

Our novel ‘Make and Test in Parallel’ approach enabled optimization of GDC-0810 formulation in a time- and cost-efficient fashion.

     

Novel γ-secretase modulators: a review of patents from 2008 to 2010

INTRODUCTION: The amyloid precursor protein is first cleaved by β-secretase to generate a 99-residue membrane-bound CTF (C99 or β-CTF), which is subsequently cleaved by γ-secretase to generate amyloid β (Aβ) peptides and the APP intracellular domain. The amyloidogenic Aβ42 has attracted considerable attention because it is thought to be the most pathogenic species associated with Alzheimer's disease progression. New classes of compounds, called γ-secretase modulators (GSMs), have been shown to selectively lower Aβ42 production without shutting down key γ-secretase-dependent signaling pathways. This has become an important therapeutic strategy aimed at modulating Aβ production. AREAS COVERED: The progress on the clinical development of γ-secretase inhibitors is briefly covered in this review, followed by a discussion of the potential differentiating attributes of GSMs. Then, the patent literature covering novel GSMs is reviewed, focusing on patents from 2008 to 2010. EXPERT OPINION: Much progress has been made in the past 2 years on developing GSMs with improved potency for lowering the production of Aβ42. However, many of these chemotypes are in a challenging chemical space and generally possess higher lipophilicity than most CNS drugs. It will be important to gain a better understanding of the specific target(s) that these GSMs interact with in order to facilitate future drug design efforts.     

Novel γ-secretase modulators: a review of patents from 2008 to 2010

Introduction: The amyloid precursor protein is first cleaved by β-secretase to generate a 99-residue membrane-bound CTF (C99 or β-CTF), which is subsequently cleaved by γ-secretase to generate amyloid β (Aβ) peptides and the APP intracellular domain. The amyloidogenic Aβ42 has attracted considerable attention because it is thought to be the most pathogenic species associated with Alzheimer's disease progression. New classes of compounds, called γ-secretase modulators (GSMs), have been shown to selectively lower Aβ42 production without shutting down key γ-secretase-dependent signaling pathways. This has become an important therapeutic strategy aimed at modulating Aβ production.

Areas covered: The progress on the clinical development of γ-secretase inhibitors is briefly covered in this review, followed by a discussion of the potential differentiating attributes of GSMs. Then, the patent literature covering novel GSMs is reviewed, focusing on patents from 2008 to 2010.

Expert opinion: Much progress has been made in the past 2 years on developing GSMs with improved potency for lowering the production of Aβ42. However, many of these chemotypes are in a challenging chemical space and generally possess higher lipophilicity than most CNS drugs. It will be important to gain a better understanding of the specific target(s) that these GSMs interact with in order to facilitate future drug design efforts.     

Effect of sulfobutyl ether-β-cyclodextrin on bioavailability of insulin glargine and blood glucose level after subcutaneous injection to rats

Insulin glargine is the first long-acting basal insulin analogue used for subcutaneous administration once daily in patients with type 1 or type 2 diabetes mellitus. To obtain the further bioavailability and the sustained glucose lowering effect of insulin glargine, in the present study, we investigated the effect of sulfobutyl ether-β-cyclodextrin (SBE4-β-CyD), with the degree of substitution of sulfobutyl ether group of 3.9, on pharmaceutical properties of insulin glargine and the release of insulin glargine after subcutaneous injection to rats. SBE4-β-CyD increased the solubility and suppressed aggregation of insulin glargine in phosphate buffer at pH 9.5, probably due to the interaction of SBE4-β-CyD with aromatic amino acid residues such as tyrosine of insulin glargine. In addition, SBE4-β-CyD accelerated the dissolution rate of insulin glargine from its precipitates, compared to that of insulin glargine alone. Furthermore, we revealed that subcutaneous administration of an insulin glargine solution with SBE4-β-CyD to rats enhanced the bioavailability of insulin glargine and sustained the glucose lowering effect, possibly due to the inhibitory effects of SBE4-β-CyD on the enzymatic degradation at the injection site. These results suggest that SBE4-β-CyD can be a useful excipient for sustained release of insulin glargine.     

The inclusion of fluoxetine into γ-cyclodextrin increases its bioavailability: behavioural, electrophysiological and pharmacokinetic studies

The inclusion of a drug into cyclodextrin generally results in the modification of its physical and chemical properties and sometimes can increase its oral bioavailability. The aim of this study was to compare the effects of the fluoxetine HCl/gamma-cyclodextrin complex to that of traditional fluoxetine HCl. In the forced swimming test in mice, fluoxetine HCl/gamma-cyclodextrin was more effective than fluoxetine HCl, the ED30s being, respectively, 9.5 and 16.9 mg/kg PO. Both compounds (10 mg/kg PO) were able to reduce the firing rate of dorsal raphe neurons in the rat. However, between-groups comparisons showed no significant differences between fluoxetine HCl treated animals and the vehicle group, while fluoxetine HCl/gamma-cyclodextrin appeared significantly more effective than vehicle from minute 25 of the measurement period. In healthy volunteers, the relative oral bioavailability, calculated as the ratio AUC 0-infinity fluoxetine HCl/gamma-cyclodextrin on AUC 0-infinity fluoxetine HCl (20 mg PO), was equal to 249.9%. The three experiments taken together suggest that the complexation of fluoxetine HCl into gamma-cyclodextrin increases its pharmacological efficacy in animals, this effect being related to an enhancement of its oral bioavailability as demonstrated in human healthy subjects.     

Effect of sulfobutyl ether-β-cyclodextrin and propylene glycol alginate on the solubility of clozapine

Clozapine (CLZ) is an atypical antipsychotic medication used in the treatment of schizophrenia and is poorly soluble in water (0.05?mM). In this study, we have investigated the effect of β-cyclodextrin (CD) and its derivatives on the solubility of CLZ. The solubility of the CLZ was measured to generate a phase solubility diagram, and the interaction between CLZ and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) in aqueous solution was observed by ¹H- and 2D rotating-frame Overhauser enhancement spectroscopy (ROESY)-NMR methods. Moreover, the synergistic effect of SBE-β-CD and water-soluble polymers, including polyvinylpyrrolidone, hydroxypropyl methylcellulose, carboxymethylcellulose sodium salt, polyvinyl alcohol, sodium alginate, and propylene glycol alginate (PGA), on the solubility of CLZ was investigated. The results show that the solubility of CLZ with 1 w/v% PGA was 7.6?mM, which was almost four times greater than that of CLZ without PGA in a 15?mM SBE-β-CD solution. In contrast, the solubility of CLZ with 1 w/v % PGA in an aqueous solution decreased by one-third relative to that of CLZ in a 15?mM SBE-β-CD solution. 2D ROESY-NMR indicated that a CLZ/SBE-β-CD/PGA ternary complex formed. It was found that the combination of PGA and SBE-β-CD enhanced the solubility of CLZ.     

Hyaluronic acid (Supartz®): a review of its use in osteoarthritis of the knee

Hyaluronic acid (Supartz?; molecular weight 620-1170?kDa) is a sterile, viscoelastic, non-pyogenic solution that is indicated as a medical device for the treatment of pain in patients with osteoarthritis of the knee who have failed to respond adequately to conservative nonpharmacological therapy and simple analgesics. Intra-articular injections of Supartz? were significantly more effective than control injections, according to an integrated longitudinal analysis of pooled data from five randomized, double-blind, vehicle-controlled, multicentre trials in patients with osteoarthritis of the knee. Supartz?, compared with the phosphate-buffered saline control, significantly reduced the total Lesquésne Index score in the post-injection period. Data from the individual trials demonstrated that the reduction in the total Lesquésne Index score was significantly greater than the control in two of the five studies. According to another efficacy endpoint (the mean reduction in the Western Ontario and McMaster Universities Osteoarthritis Index), which was assessed in only one of these trials, Supartz? was significantly more effective than the control in reducing the pain and stiffness subscale scores. Clinical scores of pain/inflammation and visual analogue scale (VAS) scores of pain during walking improved from baseline values for up to 6 months after treatment with Supartz? or a corticosteroid, with no significant between-group differences, in a small, randomized, open-label, multicentre trial in patients with osteoarthritis of the knee. Intra-articular injections of both Supartz? and Synvisc?, as well as a phosphate-buffered saline control, significantly reduced VAS scores of weight-bearing pain versus baseline after 26 weeks of therapy in a well designed trial; however, there were no significant differences between the three treatment groups. Neither hyaluronic acid formulation had a longer duration of clinical benefit than the saline control. Supartz? was well tolerated in patients with osteoarthritis of the knee. An integrated analysis of the five, well designed clinical trials demonstrated no significant difference between the Supartz? or control groups in the incidence of adverse events. The most common adverse events reported in Supartz? recipients were arthralgia, arthropathy/arthrosis/arthritis, back pain, nonspecific pain, injection-site reaction, headache and injection-site pain.     

Identification and Control of a Degradation Product in Avapro™ Film-Coated Tablet: Low Dose Formulation

A degradation product was formed during the long-term stability studies (LTSS) of the low dose formulation of Avapro? film-coated tablet. The degradant was identified as the hydroxymethyl derivative (formaldehyde adduct) of the drug substance, irbesartan, based upon analysis with LC/MS, LC/MS/MS, and chromatographic comparison to the synthetic hydroxymethyl degradation product. Laboratory studies demonstrated that the interaction of individual excipients with the drug substance at elevated temperature and polyethylene glycol (PEG) used in the coating material, Opadry? II White, leads to the generation of this formaldehyde adduct. Spiking of formaldehyde to the solution of drug substance gradually produced this impurity and the kinetics studies demonstrated that the reaction between formaldehyde and irbesartan is a second order reaction with a rate constant of 2.6?×?10^?4 M^?1min^?1 at 25°C in an aqueous media. The redevelopment of the formulation by eliminating PEG from the Opadry? II White dry-blend system was enabled by understanding the formaldehyde adduct formation.     

The Protective Effect of Inhaled Levomepromazine (Nozinan®) on Histamine-induced Bronchial Constriction

Summary: The effect of inhaled levomepromazine (Nozinan®, Veractil®) on bronchial responsiveness to inhaled histamine was investigated in asthmatics. In a double blind, randomized controlled study, 12 asthmatics (FEV₁% pred 52-96%, and PC₂₀ histamine 1.01 mg/ml (geometric mean)) were challenged before and after inhalation of levomepromazine in three different doses. Before and after each inhalation of levomepromazine, PC₂₀, FEV₁, the continuous reaction time (CRT) and the subjective sedation score (VAS) were determined. A dose-dependent increase in PC₂₀ was observed after inhalation of levomepromazine. PC₂₀ was increased by up to 4.02 two-fold concentration differences (doubling), i.e. up to a 38-fold increase from the basic values. Inhalation of the two higher doses of levomepromazine had a small sedative effect evaluated from an increase in CRT and the VAS-score and corresponding to the plasma concentrations. We conclude that inhaled levomepromazine has a dose-dependent protective effect on histamine-induced bronchial hyperresponsiveness in asthmatics and that inhalation of levomepromazine was well tolerated. The mechanism by which levomepromazine acts on histamine-induced bronchial hyperresponsiveness is not known but it could be partly explained by the antihistaminic effect. In this respect levomepromazine bears comparison with the most potent second generation antihistamines. The plasma concentrations of levomepromazine measured corresponded to those seen after oral intake of 5-10 mg levomepromazine.     

Effectiveness of a substituted β-cyclodextrin to prevent cyclosarin toxicity in vivo

Standard treatment of poisoning by organophosphorus (OP) nerve agents with atropine and an oxime has a limited efficacy. An alternative approach is the development of stoichiometric or catalytic (bio-)scavengers which should be able to prevent systemic toxicity. Recently, a β-cyclodextrin derivative, 6-OxP-CD, bearing a pyridinium oximate in 6-position of one glucose unit was synthetized and shown to possess a promising detoxification potential against a variety of alkyl methylfluorophosphonates in vitro. In order to investigate the suitability of 6-OxP-CD as a small molecule scavenger an in vivo guinea pig model was established to determine the protective effect of 6-OxP-CD against the highly toxic nerve agent cyclosarin. Prophylactic i.v. injection of 6-OxP-CD (100 mg/kg) prevented systemic toxicity in cyclosarin (∼2LD₅₀) poisoned guinea pigs, preserved brain acetylcholinesterase (AChE) activity but did not protect erythrocyte AChE activity. A lower 6-OxP-CD dose (50 mg/kg) reduced systemic toxicity and prevented mortality in all animals. Thus, the results of this proof of concept study indicate that 6-OxP-CD may be considered as a potential small molecule scavenger to protect against the toxic effects of a range of highly toxic OP nerve agents.     

Comparative bioavailability study of cefuroxime axetil (equivalent to 500 mg cefuroxime/tablet) tablets (Zednad® versus Zinnat®) in healthy male volunteers

This study was performed to investigate the bioequivalence of cefuroxime axetil tablets between a generic test product (A) Zednad? Tablet (500 mg cefuroxime/ tablet, Diamond Pharma, Syria), and the Reference Product (B) Zinnat? Tablet (500 mg cefuroxime/tablet, GlaxoSmithKline, Saudi Arabia). The bioavailability study was carried out for 24 healthy male volunteers. The subjects received 1 Zednad? Tablet (500 mg/ tablet) and 1 Zinnat? Tablet (500 mg/tablet) in a randomized, two-way crossover design fashion on 2 treatment days, after an overnight fast of at least 10 h, with a washout period of 7 days. 24 volunteers plus 2 alternatives completed the crossover. The bioanalysis of clinical plasma samples was accomplished by HPLC method, which was developed and validated in accordance with international guidelines. Pharmacokinetic parameters, determined by standard non-compartmental methods, and ANOVA statistics were calculated using SAS Statistical Software. The significance of a sequence effect was tested using the subjects nested in sequence as the error term. The 90% confidence intervals for the ratio between the test and reference product pharmacokinetic parameters of AUC0→t, AUC0→∞, and Cmax were calculated and found to be within the confidence limits of 80.00 - 125.00% for AUC0→t, AUC0→∞ and Cmax. The study demonstrated that the test product (A) was found bioequivalent to the reference product (B) following an oral dose of 500 mg tablet. Therefore, the two formulations were considered to be bioequivalent.