The effect of D-(+)-glucosamine, N-acetyl-D-glucosamine and tetraethylene glycol on the stability of oxytocin in aqueous solution.

The aim of the present study was to identify the effect of D-(+)-glucosamine, N-acetyl-D-glucosamine, tetraethyleneglycol, and the mixture of these additives on the stability of oxytocin in phosphate and acetate buffer solutions, at pH 4.5. Our findings demonstrate that tetraethyleneglycol has a destabilizing effect on oxytocin in both phosphate buffer and acetate buffer. D-(+)-Glucosamine hydrochloride had small to negligible effect at low concentrations, yielding a slight improvement lower concentrations of the additive in the presence of the buffers used, but at higher concentrations it increased the rate of degradation. N-Acetyl-D-glucosamine showed a possibly slight improvement to the stability of oxytocin. It is hypothesized that the different effect of N-acetyl-D-glucosamine compared to D-(+)-glucosamine is a consequence of the free amine group in D-(+)-glucosamine promoting a faster degradation, while the amino group is acetylated in N-acetyl-D-glucosamine and therefore no longer reactive in the same way. While it remains unclear why tetraethyleneglycol has a destabilizing effect on oxytocin, the D-(+)-glucosamine results aid in deepening our understanding of the degradation mechanism of oxytocin.

Evaluation of in vitro mucoadhesiveness and texture profile analysis of doxycycline in situ hydrogels.

Delivery of active ingredients to the oral mucosa from topically applied formulations reduces side effects from systemic administration and enhances the treatment efficiency. The challenge however, is to maintain the formulation at the administration site due to rapid salivary flow and mechanical movements of the mouth. Therefore, addition of mucoadhesive polymers could aid in enhancing the formulation residence time by increasing the mucoadhesion capacity but this effect is negligible especially if low ratio of mucoadhesive polymers are added to the formulation. Different mucoadhesive polymers at 0.5% w/w (either single or combination of two polymers) were added to the hydrogels and tested for mucoadhesion capacity, tensile strengths, adhesiveness, cohesiveness, compressibility and hardness. 0.5% povidone showed significantly highest work of mucoadhesion, 0.5% Carbopol formulation showed least cohesiveness and 0.5% HPMC showed highest adhesiveness, but a formulation containing a combination of 0.25% HPMC and 0.25% povidone showed the ideal parameters among all the mucoadhesive polymers tested. The effect of increase in concentration of HPMC (0.5, 1, 1.5, 2%) showed linear relationship for work of mucoadhesion and tensile strengths whereas for TPA the values were non-linear. The drug release from the optimized polymer matrices was found to follow zero-order release profile and the mechanism was found to be super case-II transport relaxation release. The results of this study indicate the mucoadhesive polymers do not impact the tensile strengths (p =0.05), but the texture properties and work of mucoadhesion of the formulations can be significantly (p <0.05) altered by the choice of mucoadhesive component at 0.5%w/w, though not for all the polymers tested. The study provides scope to predict in vivo performance and helps optimize for localized delivery.

Impact of changes to reimbursement of fixed combinations of inhaled corticosteroids and long-acting ß2 -agonists in obstructive lung diseases: a population-based, observational study.

BACKGROUND: In 2010, the Icelandic government introduced a new cost-saving policy that limited reimbursement of fixed inhaled corticosteroid/long-acting ß2 -agonist (ICS/LABA) combinations. METHODS: This population-based, retrospective, observational study assessed the effects of this policy change by linking specialist/primary care medical records with data from the Icelandic Pharmaceutical Database. The policy change took effect on 1 January 2010 (index date); data for the year preceding and following this date were analysed in 8241 patients with controlled/partly controlled asthma and/or chronic obstructive pulmonary disease (COPD) who had been dispensed an ICS/LABA during 2009. Oral corticosteroid (OCS) and short-acting ß2 -agonist (SABA) use, and healthcare visits, were assessed pre- and post-index. RESULTS: The ICS/LABA reimbursement policy change led to 47.8% fewer fixed ICS/LABA combinations being dispensed during the post-index period among patients whose asthma and/or COPD was controlled/partly controlled during the pre-index period. Fewer ICS monocomponents were also dispensed. A total of 48.6% of patients were no longer receiving any respiratory medications after the policy change. This was associated with reduced disease control, as demonstrated by more healthcare visits (44.0%), and more OCS (76.3%) and SABA (51.2%) dispensations. CONCLUSIONS: Overall, these findings demonstrate that changes in healthcare policy and medication reimbursement can directly impact medication use and, consequently, clinical outcomes and should, therefore, be made cautiously.

Localized rotational activation in the left atrium during human atrial fibrillation: relationship to complex fractionated atrial electrograms and low-voltage zones.

BACKGROUND: In humans, the existence of rotors or reentrant sources maintaining atrial fibrillation (AF) and the underlying electroanatomic substrate has not been well defined. OBJECTIVE: Our aim was to determine the prevalence of localized rotational activation (RotA) in the left atrium (LA) during human AF and whether complex fractionated atrial electrograms (CFAEs) or low-voltage areas colocalize with RotA sites. METHODS: We prospectively studied 32 patients (mean age 57 ± 8 years; 88% with persistent AF) undergoing AF catheter ablation. Bipolar electrograms were recorded for 2.5 seconds during AF using a roving 20-pole circular catheter in the LA. RotA was defined as sequential temporal activation of bipoles around the circular catheter. Bipolar electrogram fractionation index and bipolar voltage were used to define CFAEs and low-voltage areas, respectively. RESULTS: In 21 (66%) patients, 47 RotA sites were identified. Few (9%) lasted 2.5 seconds (cycle length 183 ± 6 ms), while the majority (91%) were nonsustained (duration 610 ± 288 ms; cycle length 149 ± 11 ms). RotA was most common in the pulmonary vein antrum (71%) and posterior LA (25%). CFAEs were recorded from 18% ± 12% of LA area, and most (92% ± 7%) were not associated with RotA sites. However, 85% of RotA sites contained CFAEs. Very low voltage (<0.1 mV) areas comprised 12% ± 10% of LA area and were present in 23% of RotA sites. CONCLUSIONS: In patients with predominantly persistent AF, localized RotA is commonly present but tends to be transient (<1 second). Although most CFAEs do not colocalize with RotA sites, the high prevalence of CFAEs and very low voltages within RotA sites may indicate slow conduction in diseased myocardium necessary for their maintenance.

Potential negative consequences of non-consented switch of inhaled medications and devices in asthma patients.

BACKGROUND: Asthma requires individually tailored and careful management to control and prevent symptoms and exacerbations. Selection of the most appropriate treatment is dependent on both the choice of drugs and inhaler device; however, financial pressures may result in patients being switched to alternative medications and devices in an attempt to reduce costs. AIM: This review aimed to examine the published literature in order to ascertain whether switching a patient's asthma medications or device negatively impacts clinical and economic outcomes. MATERIALS AND METHODS: A literature search of MEDLINE (2001-13 September 2011) was conducted to identify English-language articles focused on the direct impact of switching medications and inhaler devices and switching from fixed-dose combination to monocomponent therapy via separate inhalers in patients with asthma; the indirect impacts of switching were also assessed. RESULTS: Evidence showed that non-consented switching of medications and inhalers in patients with asthma can be associated with a range of negative outcomes, at both individual and organisational levels. Factors that reduce adherence may lead to compromised symptom control resulting in increased healthcare resource utilisation and poorer patient quality of life. DISCUSSION: The consequences of a non-consented switch should be weighed carefully against arguments supporting an inhaler switch without the patient's consent for non-medical/budgetary reasons, such as potential reductions in initial acquisition costs, which may be associated with subsequent additional healthcare needs. CONCLUSION: Given the increasing pressure for reduced costs and efficient allocation of limited healthcare resources, an additional investment in ensuring high medication adherence may lead to greater savings due to a potentially decreased demand for healthcare services. In contrast, savings achieved in acquisition costs may result in a greater net loss due to increased healthcare consumption caused by decreased asthma control.

Effects of complete heart block on myocardial function, morphology, and energy metabolism in the rat.

AIMS: Severe sustained bradycardia may cause acute and possibly chronic congestive heart failure (CHF). The aim of this study was to investigate acute and chronic effects of complete heart block (CHB) on cardiac function, morphology, and creatine (Cr) metabolism. METHODS AND RESULTS: CHB was induced in male Sprague-Dawley rats (approximately 250 g, n = 11) by means of electrocautery applied to the region of AV node and were compared with controls (n = 15). The rats were investigated at 1, 3, and 12 weeks after CHB induction with transthoracic echocardiography. Invasive haemodynamic assessment of left and right ventricular pressures was performed at 12 weeks. After the sacrifice, the hearts were freeze-clamped for analysis of myocardial Cr, and high energy phosphometabolites. The efficacy of operative procedure was 54%. The peri-operative mortality rate was 20%. Heart rate (HR) decreased by approximately 50% (P < 0.01) while stroke volume (SV) increased 2.5 times (P < 0.01) in the CHB rats. Cardiac index remained unchanged. The rats with CHB grew normally and were in no apparent distress. Filling pressures in left and right ventricles were normal. The CHB rats developed marked cardiomegaly with biventricular dilatation and eccentric left ventricular hypertrophy (P < 0.01). There was no change in the myocardial content of Cr and high energy phosphometabolites. CONCLUSION: Rats with CHB are compensating for reduction in HR with increased SV without haemodynamic and biochemical characteristics of CHF. This model may be useful to study the effects of CHB and bradycardia on myocardial structure, function, electrophysiology, and metabolism as well as for studies of cell therapy for reparation of AV conductance.

Electroencephalographic effects and serum concentrations after intranasal and intravenous administration of diazepam to healthy volunteers.

AIMS: To evaluate the electroencephalographic (EEG) effects, blood concentrations, vehicle irritation and dose-effect relationships for diazepam administered nasally. METHODS: The study had a cross-over design with eight healthy volunteers (one drop out). It consisted of four legs with four different administrations: intranasal (i.n.) placebo, 4 mg diazepam i.n., 7 mg diazepam i.n. and 5 mg intravenous (i.v.) diazepam. Polyethylene glycol 300 (PEG300) was used as a vehicle in the nasal formulations to solubilize a clinically relevant dose of diazepam. Changes in N100, P200 and P300 brain event-related potentials (ERP) elicited by auditory stimulation and electroencephalographic beta-activity were used to assess effects on neurological activity. RESULTS: The mean [95% confidence intervals] differences between before and after drug administration values of P300-N100 amplitude differences were -0.9 [-6.5, 4.7], -6.4 [-10.1, -2,7], -8.6 [-11.4, -5.8] and -9.6 [-12.1, -7.1] for placebo, 4 mg i.n., 7 mg i.n. and 5 mg i.v. diazepam, respectively, indicating statistically significant drug induced effects. The bioavailabilities of 4 and 7 mg i.n. formulations, were found to be similar, 45% [32, 58] and 42% [22, 62], respectively. CONCLUSION: The present study indicates that it is possible to deliver a clinically effective nasal dose of diazepam for the acute treatment of epilepsy, using PEG300 as a solubilizer.

Serum amyloid P component inhibits influenza A virus infections: in vitro and in vivo studies.

Serum amyloid P component (SAP) binds in vitro Ca(2+)-dependently to several ligands including oligosaccharides with terminal mannose and galactose. We have earlier reported that SAP binds to human influenza A virus strains, inhibiting hemagglutinin (HA) activity and virus infectivity in vitro. These studies were extended to comprise five mouse-adapted influenza A strains, two swine influenza A strains, a mink influenza A virus, a ferret influenza A reassortant virus, a influenza B virus and a parainfluenza 3 virus. The HA activity of all these viruses was inhibited by SAP. Western blotting showed that SAP bound to HA trimers, monomers and HA1 and HA2 subunits of influenza A virus. Binding studies indicated that galactose, mannose and fucose moieties contributed to the SAP reacting site(s). Intranasal administration of human SAP to mice induced no demonstrable toxic reactions, and circulating antibodies against SAP were not detected. Preincubation of virus (A/Japan/57) with SAP prevented primary infection of mice and development of antiviral antibodies. After a single intranasal administration of SAP (40 microg) 1 h before primary infection with virus (2LD(50)), nine out of 10 mice survived on day 10 and these mice approached normal body weight, whereas control mice (one out of five surviving on day 10) died. The data provide evidence of the potential of intranasally administered SAP for prophylactic treatment of influenza A virus infections in humans.

[Attitude of the Icelandic population towards performing cardiopulmonary resuscitation on strangers in the pre-hospital setting.].

OBJECTIVE: Initiation of bystander cardiopulmonary resuscitation (CPR) is directly linked to the outcome of cardiac arrest in the community. Recent reports have indicated a reluctance among witnesses to perform CPR on strangers especially mouth to mouth ventilation. The status of this in Iceland is unknown. The objective of this study was to assess the attitude of Icelanders towards bystander CPR. MATERIAL AND METHODS: A telephone survey was conducted on 1200 randomly selected Icelanders, aged 16-75 years, with regard to their attitude towards pre-hospital CPR on strangers. A total of 804 (70.1%) chose to participate. RESULTS: A large number had received some kind of training in CPR (73%), wheras only 6% had actually participated in CPR. In accordance, 50% thought they would be able to perform chest compressions adequately and 55% mouth to mouth ventilation. A total of 491 (65%) would likely volunteer to perform chest compressions on a stranger, while 178 (24%) would not and 84 (11%) were undecided. Similarly, 473 (64%) would likely volunteer to perform mouth to mouth ventilation on a stranger. One hundred seventy seven (24%) would not and 93 (12%) were unsure. An overwhelming majority, 620 (81%) said it would not make any difference regarding their participation in CPR if the procedure was simplified and included only chest compressions but not mouth to mouth ventilation. CONCLUSIONS: Icelanders have a very positive attitude towards bystander CPR, over two thirds have had some kind of CPR instruction and a large majority has no aversion towards performing mouth to mouth ventilation on strangers. These results are in contrast to similar data from the United States.

Intranasal absorption of buprenorphine--in vivo bioavailability study in sheep.

The bioavailability of buprenorphine, HCl (BPP) in sheep after nasal administration of two formulations has been studied. 0.9 mg BPP in 150 microl was administered nasally and compared to 0.6 mg i.v. The test solutions were formulated with 30% polyethylene glycol 300 (PEG 300) and 5% dextrose, respectively. The bioavailability for PEG 300 was 70% (S.D.+/-27%, n=6), whereas the bioavailability for 5% dextrose was 89% (S.D.+/-23%, n=6). A two-compartment model with initial and terminal serum half-lives of 10 and 23 min, respectively, may describe the pharmacokinetics. The rate of absorption for both nasal formulations was very fast (t(max)=10 min). The C(max) was 37 ng/ml (S.D.+/-17) and 48 (S.D.+/-10) for PEG 300 and dextrose, respectively. No significant difference was found between the two formulations, but PEG 300 has advantages in relation to freezing point depression and solubility, which may be considered if further studies are going to be initiated. The high nasal bioavailability and short time to maximal plasma concentration suggests that it is possible to make a clinically relevant nasal formulation of BPP for the treatment of pain.

Intranasal immunization with pneumococcal polysaccharide conjugate vaccines protects mice against invasive pneumococcal infections.

Host defenses against Streptococcus pneumoniae depend largely on opsonophagocytosis mediated by antibodies and complement. Since pneumococcus is a respiratory pathogen, mucosal immune responses may play a significant role in the defense against pneumococcal infections. Thus, mucosal vaccination may be an alternative approach to current immunization strategies, but effective adjuvants are required. Protein antigens induce significant mucosal immunoglobulin A (IgA) and systemic IgG responses when administered intranasally (i. n.) with the glyceride-polysorbate based adjuvant RhinoVax (RV) both in experimental animals and humans. The immunogenicity and efficacy of pneumococcal polysaccharide conjugate vaccines (PNC) of serotypes 1 and 3 was studied in mice after i.n. immunization with RV. Antibodies were measured in serum (IgM, IgG, and IgA) and saliva (IgA) and compared to antibody titers induced by parenteral immunization. The PNCs induced significant systemic IgG and IgA antibodies after i.n. immunization only when given with RV and, for serotype 1, serum IgG titers were comparable to titers induced by subcutaneous immunization. In addition, i.n. immunization with PNC-1 in RV elicited detectable mucosal IgA. These results demonstrate that RV is a potent mucosal adjuvant for polysaccharides conjugated to proteins. A majority of the PNC-1-immunized mice were protected against both bacteremia and pneumonia after i.n. challenge with a lethal dose of serotype 1 pneumococci, and protection correlated significantly with the serum IgG titers. Similarly, the survival of mice immunized i.n. with PNC-3 in RV was significantly prolonged. These results indicate that mucosal vaccination with PNC and adjuvants may be an alternative strategy for prevention against pneumococcal infections.

Single- and repeated-dose local toxicity in the nasal cavity of rabbits after intranasal administration of different glycols for formulations containing benzodiazepines.

To furnish a systemic effect after intranasal administration, a formulation must contain the therapeutic dose in no more than 150 L, the maximum volume that can be applied as a single administration in one nostril in man. The objectives of these studies were to examine the local toxicity of formulations containing benzodiazepines and to document the effects to support clinical trials in man. After stability, pharmacological and pharmacokinetic studies of several benzodiazepine formulations, we studied nasal toxicity after single and repeated administration to rabbits of poly(ethylene glycol) 200, tetra(ethylene glycol), glycofurolum and mixtures of these vehicles both with and without benzodiazepines. Single-dose studies with examinations 5 or 10min after application were undertaken with poly(ethylene glycol), tetra(ethylene glycol), glycofurolum and tetra(ethylene glycol)-glycofurolum in the ratio 95:5; the reactions were similar to that after physiological saline. A 14-day repeated-dose study was conducted with diazepam, lorazepam and flunitrazepam formulations in poly(ethylene glycol), and flunitrazepam in poly(ethylene glycol)-glycofurolum in the ratio 70:30; the two vehicles without any benzodiazepine were also examined. Microscopic study revealed mild changes only in the treated groups. A final four-week study was conducted with repeated administration of clonazepam formulated in tetra(ethylene glycol)-glycofurolum in the ratio 95:5; microscopy revealed mild changes after three 150-microL doses daily, but no abnormalities after one or three 100-microL doses daily. It was concluded that these three solvents individually or as mixtures resulted in only mild local toxicity and might be acceptable as vehicles in nasal preparations of benzodiazepines and other non-irritating drugs for short-term use in man.

Intranasal administration of diazepam aiming at the treatment of acute seizures: clinical trials in healthy volunteers.

Intranasal administration of diazepam may be a practical alternative to the conventional acute medication of seizures, such as status epilepticus. Nine healthy students participated in an open crossover study on intranasal versus intravenous administration of diazepam (2 mg). Blood samples were collected, pharmacodynamic tests were performed, and the volunteers filled out questionnaire. Peak concentration was achieved after 18+/-11 min and the bioavailability was 50.4+/-23.3%. A pharmacodynamic effect was observed after about 5 min, but the dose, even for i.v. administration, was too low to generate a strong measurable effect. The results indicate that intranasally administered diazepam may be an effective alternative to i.v. administration in relief of seizures, e.g. in an acute situation when a physician or nurse is not available on location.

Selective augmentation of antibodies in various mucosal regions, after intranasal immunization with diphtheria in mice.

The kinetics of antibody responses were analyzed in various mucosal membranes as well as in the blood and the spleen after intranasal vaccination of mice with diphtheria toxoid. The results show a selective increase in antibody response in the respiratory area and the vagina followed by the gastrointestinal tract, but not in the spleen. IgG and IgM showed an increase 7 days after revaccination, followed by a rapid decline. However, IgA peaked 3 days after revaccination and did not decline throughout the study.

Intranasal vaccination: pharmaceutical evaluation of the vaccine delivery system and immunokinetic characteristics of the immune responses.

The purpose of this study was to analyze the effect of some pharmaceutical excipients when used for mucosal vaccine formulations and to characterize the achieved immune response. After conducting various pharmaceutical evaluations of the formulations, immunokinetic studies were performed in mice, guinea pigs, and rabbits. The kinetics and the characteristics (antibody isotypes, etc.) of the immune response were studied, as well as the induced level of toxin neutralizing IgG antibodies, which are usually used as the only measures of the potency of vaccines. Results in mice show that intranasal vaccination results in a potent and rapid immune response, similar to that seen after subcutaneous immunization. In guinea pigs and rabbits, however, the subcutaneous immunization produced significantly stronger response than did intranasal vaccination. The most promising excipients were found to be either Polysorbate 20 or Cremophor EL in an aqueous mixture together with caprylic/capric glyceride. The results indicate that nontoxic and pharmaceutically acceptable excipients can be used for mucosal vaccination, providing an interesting alternative to parenteral vaccination.

Clinically relevant vaccine-vaccine interactions: a guide for practitioners.

The need for combination vaccines has been recognised for many years. Many children must have 9 or 12 injections in their first year, which places a considerable burden on the child and the health service. Combination vaccines or simultaneously administered vaccines need to generate a protective immune response to all vaccine components that is equivalent to the response when administered separately. This is not always the situation. Many vaccines should not be administered together because of adverse reactions known as vaccine-vaccine interactions, a phenomenon where one vaccine affects another vaccine, thus potentially causing loss of immunogenicity, loss of protective efficacy or induction of adverse reactions. It is important to remember that most vaccine-vaccine interactions are asymptomatic and may only be discovered when the immune status of the vaccine recipient is analysed or when the individual is challenged by the microbe. The interactions may occur because of physical or chemical interactions within the vaccine formulation, interactions between live vaccines or immunological interference. This review summarises known vaccine-vaccine interactions that have been critically analysed and categorised based on their clinical importance.

Pharmacokinetic and pharmacodynamic response after intranasal administration of diazepam to rabbits.

Nasal application of drugs might be an alternative to intravenous administration in acute situations such as epileptic or fever seizures. In the search for a nasal formulation leading to a peak plasma concentration of diazepam at a tmax < or = 5 min bioavailability in rabbits has been studied after intranasal administration of the drug in ten vehicles of different polarity. The animals were dosed with 3 mg diazepam, dissolved in 100 microL vehicle, the solution being administered into both nostrils. The bioavailability, measured during the first 30 min, because periods after this are not relevant for acute treatment, was found to be between 49 and 62% for the four most promising vehicles, pure glycofurol 75, tetraethyleneglycol, poly(ethylene glycol) 200 and 30% glycofurol in tetraethyleneglycol. The tmax for these vehicles was achieved after 5 min, and they induced a very rapid pharmacodynamic response after 1.5 to 3.5 min. The bioavailability was reduced when more polar liquids such as ethanol and tween 20, or lipid oils, e.g. vegetable oil and miglyol 840 were added to the glycofurol. There was a good correlation between tmax and the induction of pharmacodynamic response. These results suggest that nasal application of diazepam in a water-free low-molecular-weight glycol might be of clinical importance as an alternative to intravenous injection, especially in acute situations.

Intranasal booster vaccination against diphtheria and tetanus in man.

The booster responses of three different formulations of intranasal (i.n.) diphtheria-tetanus (D-T) vaccines were determined in military recruits and compared with a conventional subcutaneous D-T vaccine. The vaccines for mucosal delivery were sprayed into one nostril and contained D and T toxoids in an enhancer mixture of polysorbate and caprylic/capric glycerides. All of the vaccines gave rise mainly to a systemic IgG response. Among 51 persons with anti-D antibody concentrations in serum below a protective level of 0.01 international units (IU ml-1) before vaccination, all except two attained protective antibody concentrations 4 weeks after vaccination. The median increase in anti-D antibody concentration was 113-fold with the most efficient i.n. formulation. The median increase in anti-T antibody level was 2.4-fold, however, the pre-vaccination levels for this antigen were very high. Within the examined levels, the booster response depended mainly on the dose of the antigen in the vaccine rather than on the concentration of the vehicle mixture. Compared with the parenteral D-T vaccine containing aluminium hydroxide as an adjuvant, all of the tested i.n. formulations showed somewhat lower immunogenicity in man as well as in pre-clinical guinea-pig studies. Among 215 persons immunized i.n., 61% preferred this route of administration rather than a parenteral injection, although the formulations were all associated with varying local symptoms, frequently stinging and pronounced, nasal secretion.