It is a well-known fact that drugs can exist in different solid-state forms. These solid-state forms can be either crystalline or amorphous. Furthermore, significant differences are identified between the different solid-state forms of the same drug. Physico-chemical properties that are affected by the solid-state include: melting point, solubility, dissolution rate, stability, compressibility, processability, to name but a few. During the last two decades a significant amount of attention was directed towards the amorphous solid-state forms of drugs. The amorphous form is the direct opposite of the crystalline solid-state. While crystalline forms are constituted by unit cells arranged in a repetitive and structured nature, amorphous forms do not have a long-range order. This lack of order leads to an increase in the Gibbs free energy of such compounds which in turn leads to increased dissolution and solubility. The advantage of improved aqueous solubility and dissolution is a sought after characteristic within the pharmaceutical industry. Improved solubility ultimately could lead to improved bioavailability of a drug. In this study the amorphous nature and stability of amorphous azithromycin was studied. Although previous studies reported that amorphous azithromycin can be easily prepared, there is not a significant amount of data available on the stability of the amorphous form. Furthermore, the effect of milling, mixing, compression, handling and storage on the amorphous form was also investigated. This study showed that amorphous azithromycin remains stable during milling, mixing and compression. A compatibility study on azithromycin when mixed with tableting excipients showed some incompatibilities and this was helpful information to assist with the choice of excipients to be included in the tablet formulation. During the formulation study it became evident that good formulation strategies can greatly improve the flow properties of a drug. The stability of amorphous azithromycin was also studied. During this phase of the study an atypical stability indicating method was used in order to determine and demonstrate the stability of amorphous azithromycin. Dissolution studies were used to illustrate the stability of amorphous azithromycin due to the fact that dissolution is the only method that indicates the phenomena of solution-mediated phase transformation of an amorphous form to a stable crystalline form. During the stability study of six months at 40°C ± 75% RH no recrystallisation of the amorphous form to the crystalline form occurred. It was concluded that amorphous azithromycin will remain stable during processing steps, product formulation and manufacturing as well as during storage for a period of six months at elevated temperature and humidity. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2015

Σκοπός της παρούσας μελέτης ήταν η διερεύνηση της εξωκυττάριας συγκέντρωσης και του βαθμού διεισδυτικότητας των νεότερων μακρολίδων στο υγρό περιεχόμενο του ιγμορείου άντρου, εντός των πρώτων 24 ωρών από την χορήγηση σε ασθενείς με οξεία παραρρινοκολπίτιδα, χρησιμοποιώντας ως μοντέλα την κλαριθρομυκίνη και αζιθρομυκίνη. Σε 36 ασθενείς με οξεία ιγμορίτιδα συλλέχθηκαν δείγματα υγρού από το ιγμόρειο άντρο και ορού αίματος 2,4,6,8 και 12 ώρες ή 2,6,12 και 24 ώρες μετά την χορήγηση τριών δόσεων ρ.ο. κλαριθρομυκίνης 500 mg δις ημερησίως ή δύο δόσεων ρ.ο. αζιθρομυκίνης 500 mg άπαξ ημερησίως αντίστοιχα. Οι συγκεντρώσεις των φαρμάκων στα δυο βιολογικά υγρά προσδιορίσθηκαν με την υγρή χρωματογραφία υψηλής απόδοσης με φθοριομετρική ανίχνευση, ενώ επίσης εκτιμήθηκε το pH σε όλα τα δείγματα υγρού παραρρίνιων. Η μέση συγκέντρωση κλαριθρομυκίνης στο υγρό παραρρίνιων κόλπων ήταν σημαντικά υψηλότερη από την αντίστοιχη της αζιθρομυκίνης (2,47 mg/l έναντι 0,65 mg/l), ενώ ο μέσος βαθμός διεισδυτικότητας στο υγρό του ιγμόρειου άντρου,εκφρασμένος ως η αναλογία των συγκεντρώσεων φαρμάκου στον ιστό και στον ορό αίματος, ήταν παρόμοια για τα δύο αντιβιοτικά (115 % και 120% αντίστοιχα). Σε ασθενείς με οξεία παραρρινοκολπίτιδα, η κλαριθρομυκίνη και η αζιθρομυκίνη παρουσιάζουν επαρκή διεισδυτικότητα στο υγρό του ιγμόρειου άντρου για την εκρίζωση στελεχών streptococcus pneumoniae ευαίσθητων στην ερυθρομυκίνη. Με βάση τις συγκρίσιμες δραστικότητες τους in vitro, την επίδραση του pH του υγρού του ιγμόρειου άντρου και το προφίλ διεισδυτικότητας στο συγκεκριμένο υγρό, συμπεραίνουμε ότι ανάμεσα στα ευαίσθητα στην ερυθρομυκίνη στελέχη streptococcus pneumoniae, η κλαριθρομυκίνη θα πλεονεκτούσε σε σχέση με την αζιθρομυκίνη στην εκρίζωση των στελεχών χαμηλής αντίστασης. / The aim of this study was to investigate the extracellular concentration and the degree of sinus fluid penetration of newer macrolides, during the first 24-48 hours of treatment in patients with acute bacterial rhinosinusitis (ABRS), choosing clarithromycin and azithromycin as model antibiotics. An open, noninterventional pharmacokinetic study was performed at a tertiary teaching hospital. In 36 outpatients with ABRS, sinus fluid aspirates and serum samples were collected 2, 4, 6, 8 and 12 hours or 2, 6, 12 and 24 hours after the administration of three doses of oral clarithromycin, 500mg, twice daily or two doses of oral azithromycin, 500 mg, once daily, respectively. Drug concentrations were determined in both matrices by high-performance liquid chromatography (HPLC) with fluorometric detection ,and the pH was estimated for all sinus fluid samples. The average clarithromycin sinus fluid concentration was found to be significantly higher than the corresponding azithromycin concentration (2.47mg/L versus 0.65 mg/L), while the extent of the average sinus fluid penetration, expressed by the ratio of drug concentration in tissue versus serum, was similar for both drugs (115% and 120% respectively). In patients with ABRS, clarithromycin and azithromycin, present adequate penetration into sinus fluid to eradicate erythromycin-sensitive strains of S. pneumoniae. Considering their comparative in vitro activity, the sinus fluid pH effect and their sinus fluid penetration profile, we may conclude that among the erythromycin-resistant S. pneumoniae strains, clarithromycin might be advantageous over azithromycin in eradicating some of the low-level resistant strains.

The use of the oral route of administration for the treatment of young children with antibiotics can at times be problematic since, factors such as nausea, vomiting, taste and/or smell, in addition to the challenges associated with the administration of suspensions, may contribute to poor patient compliance. In such cases, the use of the rectal route of administration may be appropriate. Therefore, suppositories containing 250 mg azithromycin (AZI) were manufactured and assessed for potential as an antibiotic suppository dosage form. Suppositories, containing AZI dihydrate were manufactured by the fusion method, using different grades of PEG, Witepsol® and Suppocire® bases. The rate and extent of AZI release was evaluated using USP apparatus I, and samples were analyzed using a validated HPLC method. Differences in the rate and extent of AZI release were observed with the greatest amount of AZI being released from PEG formulations. The rate and extent of AZI release from formulations manufactured using fatty bases were influenced by physicochemical properties, such as melting rate and hydroxyl value, of the bases. In addition drug partitioning appeared to favor the lipid phase and had a negative impact on AZI release characteristics. Two different formulation approaches were used in an attempt to increase the rate and extent of AZI release from fatty base formulations. The use of surfactants significantly increased AZI release from formulations manufactured with fatty bases with high hydroxyl values. The use of urea or Povidone K25 in combination with AZI as a physical mixture or solid dispersion did not increase the rate and extent of AZI release from the fatty suppositories, to any significant extent. The mechanism of drug release was evaluated using several mathematical models, including the Higuchi, Korsmeyer- eppas, Zero and, First order models. In addition, in vitro dissolution profiles were characterized by the difference and similarity factors, f1 and f2 and by use of the Gohel similarity factor, Sd. AZI release kinetics were best described by the Higuchi and Korsmeyer-Peppas models and the values of the release exponent, n, revealed that drug release was a consequence of the combined effects of AZI diffusion, rate of melting of the base and partitioning of the drug which can be considered to be anomalous release.

Although a number of different antibiotics are used to combat staphylococcal infections, resistance has continued to develop. The use of rifampicin and ciprofloxacin in combination with azithromycin, known for its inhibitory effects on the bacterial ribosome, can create potential synergistic effects on ribosomal subunit synthesis rates. In this work, combination antibiotic treatments gave a significant decrease in cell numbers following growth in the presence of ciprofloxacin or rifampicin with azithromycin compared to those grown with azithromycin or rifampicin alone. DNA, RNA and protein synthesis rates were reduced with single antibiotic treatments and showed further decreases when drug combinations were used. 70S ribosome levels were reduced with every antibiotic treatment. DNA gyrase subunits A and B showed significant decreases for double and triple antibiotic-treated samples. Ribosomal subunit synthesis rates were diminished for each different antibiotic combination. Turnover of 16S and 23S rRNA was also observed in each case and was stimulated by antibiotic combinations. The frequency of spontaneous resistance was reduced in all double selections, and no triply resistant mutants were found.

No description available.

No description available.

No description available.

Introduction: Myocardial infarction (MI) remains the leading cause of morbidity and mortality worldwide. Induced by cardiomyocyte death, MI initiates a prolonged and uncontrolled inflammatory response which impairs the healing process. Immune cells, such as macrophages, play a central role in organizing the early post-MI inflammatory response and the subsequent repair phase. Two activation states of macrophages have been identified with distinct and complementary functions (inflammatory vs. reparatory). This bimodal pattern of macrophage activation is an attractive therapeutic target to favorably resolve post-MI inflammation and enhance recovery. It has been demonstrated that azithromycin (AZM), a commonly used antibiotic with immunomodulatory effects, polarizes macrophages towards the reparatory phenotype. AZM has an excellent safety profile and has been approved for human use. We hypothesize that AZM reduces inflammation and improves heart function in MI. Methods and results: In our initial studies, we demonstrated that oral free AZM (160 mg/kg daily for 7 days), initiated 3 days prior to MI, enhances post-MI cardiac recovery as a result of shifting macrophages to the reparatory state. We observed a significant reduction in mortality with AZM therapy. AZM-treated mice showed a significant decrease in pro-inflammatory and an increase in reparative macrophages, decreasing the pro-inflammatory/reparative macrophage ratio. Macrophage changes were associated with a significant decline in pro- and an increase in anti-inflammatory cytokines. Additionally, AZM treatment was correlated with a distinct decrease in neutrophil count due to apoptosis, a known signal for shifting macrophages towards the reparative phenotype. Finally, AZM treatment improved cardiac recovery, scar size, and angiogenesis. We designed this proof of concept study using pre-MI AZM therapy to achieve steady state levels prior to injury. Therefore, in our follow-up studies we targeted inflammatory macrophages using a non-Pegylated liposomal formulation of AZM (Lazm) which has been shown in multiple studies to promote drug efficacy and minimize off-target effects. To test the hypothesis that Lazm is more effective and safer than free AZM, low doses of free/liposomal AZM (10 or 40 mg/kg, administered intravenously) were initiated immediately after MI. We observed that Lazm induces early resolution of the post-MI inflammatory response as evidenced by switching of the activation state of monocytes/macrophages towards the reparatory phenotype. Neutrophils were substantially decreased, particularly pro-inflammatory neutrophils. Cytokine profiles were also shifted to the anti-inflammatory status with Lazm therapy. Taken together, AZM treatment resulted in a significant shift in macrophage activation towards the reparatory state. The shift in inflammatory state was accompanied by a decrease in apoptosis and infarct size in the injured heart, as well as enhanced angiogenesis and LV functional recovery in our long-term studies. In addition, Lazm was protective against off-target effects of AZM on the heart. Conclusion: This is the first evidence of a novel and clinically-relevant therapeutic strategy to modulate post-MI inflammation. We found that AZM reduces cardiac inflammation and improves adverse cardiac remodeling after infarction via promoting a shift of macrophage activation state. The overarching significance of this work is the modulation of sterile inflammation, which can be a viable therapeutic target in many conditions including stroke and heart attack. Additionally, this is the first study to demonstrate the immune modulation properties of liposomal AZM, which has wide potential therapeutic applications beyond the cardiovascular field. Importantly, liposomal formulation of AZM is protective from its cardiac off-target effects. Our findings strongly support clinical trials using AZM as a novel and clinically relevant therapeutic target to improve cardiac recovery and reduce heart failure post-MI in humans.

Patients with cystic fibrosis who are infected with the pathogen Pseudomonas aeruginosa have shown favorable responses to the drug azithromycin (AZM). This drug works in an anti-inflammatory capacity, improving clinical outcomes and improving quality of life in this population. The drug has also been shown to affect macrophage polarization by shifting these cells away from an inflammatory phenotype toward an alternatively activated anti-inflammatory phenotype. The full impact of this phenotypic change is not well understood in the context of the response to P. aeruginosa infection, or the overall immune response in cystic fibrosis. To understand how the AZM-polarized macrophage affects other types of cells, we utilized a co-culture in vitro system, with macrophages and fibroblasts incubating together. In this system, we determined that AZM causes upregulation of the pro-fibrotic mediator transforming growth factor-β as well as the extracellular matrix (ECM) protein fibronectin. The mediator of ECM turnover, matrix metalloproteinase (MMP)-9 was upregulated in this system as well. In an in vivo model of P. aeruginosa infection, MMP- 9 and fibronectin were increased in the bronchoalveolar lavage 7 days post-infection in mice that were treated with AZM. This was accompanied by a decrease in damage to the lung tissue, determine by histological examination. To determine if these changes would continue in human subjects with cystic fibrosis, a clinical study was done in this population. Subjects with AZM treatment had decreased TGF-β levels, but no differences in MMP-9 or fibronectin. Interestingly, correlations between certain fibrotic mediators and inflammatory cytokines, specifically interleukin -1β, were different in subjects with AZM treatment compared to subjects without AZM therapy. Together, these data indicate that AZM alters the fibrotic response from the macrophages, as well as the interaction of the inflammatory response and fibrosis development.

Made available in DSpace on 2016-04-28T20:15:24Z (GMT). No. of bitstreams: 1 2007- Ingrid Annes Pereira.pdf: 915318 bytes, checksum: 2dd2600d64dd3aa95cfa91ab1bd4177c (MD5) Previous issue date: 2007-02-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Antimicrobial resistance is a complex question that concerns a variety of bacterial species and resistance mechanisms, which in part can be transmitted from pet animals to the owners by theirs strict contact. The prescription of antimicrobial agents in the veterinary practices, without previous identification of the etiologic agent and its antimicrobial susceptibility pattern associated with the large use of antimicrobials applied in human medicine represent a potential source for the spread of resistant strains in animal reservoir. Azithromycin widely used in human medicine, presents bacteriostatic activity against several infectious agents, and recently it was released in Brazilian veterinary practices as an alternative for the treatment of urinary, respiratory, oral and skin infections. This work evaluated the activity pattern of azithromycin to different bacterial infections from pet animals, by the identification of the etiologic agent and its antimicrobial susceptibility pattern, and also determinate MIC values and evaluate cross-resistance to oxacilin and azithromycin in Staphylococcus spp., as a proposal to construct the real frame of azithromycin resistance in our region so as its use represent a reliable alternative in veterinary medicine. The samples were collected from different sites of infection in dogs and cats, like otitis externa, pyoderma, infections from the urinary, reproductive and respiratory tract, oral and conjuntival mucosas. The most prevalent bacterial agents were coagulase-positive Staphylococcus spp., followed by Entorabacteiaceae, coagulase-negative Staphylococcus spp., and Pseudomonas spp.. The isolates were most sensible to ampicilin+sulbactam, gentamicin, fluoroquinolones and some cephalosporins. The bacterial isolates showed an expressive azithromycin resistance, with exception of the isolates from urinary tract infection. Different tests were used to access the activity pattern of azithromycin, such as Disc Diffusion and Broth Microdiluition that detected 48,6% and 55% of resistants Staphylococcus spp., and 55,3% e 72,7% of resistants Gram-negative rods. Staphylococcus aureus MIC50 were 4,0 μg/mL, S. intermedius 1,0 μg/mL, coagulasenegative Staphylococcus ≥512 μg/mL and Gram-negative rods were 256 μg/mL. In nine (15%) isolates of oxacilin-resistant and mecA-positive Staphylococcus spp. were also possible detect azithromycin resistance. For this reasons, the laboratories investigations are necessary for the identification of the etiologic agents of bacterial infections and to determine its susceptibility to antimicrobials, for the best choice of treatment, and to impair the emergence of resistant bacteria that can be transmitted between animals and human, like what happens in oxacilin-resistant Staphylococcus spp.. The emergence of azithromycin resistance leads to the necessity of reliable data on the concern of the activity pattern of this antimicrobial and its contribution for the veterinary medicine practices without producing impact in development and spread of resistant strains. / A resist?ncia antimicrobiana ? um problema complexo, que envolve in?meras esp?cies bacterianas e diferentes mecanismos, podendo ter sua transmiss?o facilitada pelo estreito conv?vio entre animais de companhia e seus propriet?rios. A pr?tica de prescrever antibioticoterapia sem pr?via identifica??o do agente etiol?gico e do seu perfil de suscetibilidade associada ao amplo uso de antimicrobianos aplicados ? medicina humana representam potenciais fatores para a dissemina??o de cepas resistentes em reservat?rios animais. A azitromicina, j? amplamente utilizada no tratamento de infec??es em humanos, apresenta atividade bacteriost?tica contra uma gama de agentes infecciosos e est? dispon?vel atualmente para a cl?nica veterin?ria brasileira como alternativa de tratamento em processos infecciosos dos sistemas genito-urin?rio, respirat?rio, oral e pele. Dessa forma, o presente estudo avaliou o espectro de atividade da azitromicina, em diversos processos infecciosos bacterianos de animais de companhia, estabelecendo o pat?geno prevalente, seu perfil de suscetibilidade aos f?rmacos de elei??o, al?m de determinar a CIM da azitromicina e avaliar a poss?vel resist?ncia cruzada em Staphylococcus spp. oxacilina e azitromicina-resistentes, de forma a obter dados significativos para a constru??o do quadro real de resist?ncia ? azitromicina em nossa regi?o, para que seu uso represente uma alternativa terap?utica confi?vel em Medicina Veterin?ria. As amostras estudadas foram coletadas de diferentes processos infecciosos de c?es e gatos, tais como, otites externas, piodermas, infec??es do trato genito-urin?rio, respirat?rio, cavidade oral e da mucosa conjuntival. Os agentes bacterianos mais prevalentes foram Staphylococcus spp. coagulasepositivos, seguidos pelas enterobact?rias, Staphylococcus spp. coagulase-negativos e Pseudomas spp. De modo geral, os isolados foram mais sens?veis a ampicilina+sulbactam, gentamicina, fluoroquinolonas e algumas cefalosporinas. A azitromicina apresentou percentuais de resist?ncia significativos, com exce??o dos isolados de infec??es do trato urin?rio. Diferentes testes foram utilizados para avalia??o do perfil de atividade da azitromicina dentre estes, a Difus?o em Disco e a Microdilui??o em Caldo, detectaram resist?ncia em 48,6% e 55% dos isolados de Staphylococcus spp., respectivamente e 55,3% e 72,7% dos bastonetes Gram-negativos. A CIM50 para S. aureus foi 4,0 μg/mL, para S. intermedius 1,0 μg/mL, Staphylococcus spp. coagulase-negativos ≥512 μg/mL e bastonetes Gram-negativos 256 μg/mL. Em nove isolados (15%) de Staphylococcus spp. resistentes ? oxacilina e mecA positivos foi poss?vel tamb?m detectar resist?ncia ? azitromicina. Logo, a investiga??o laboratorial de doen?as bacterianas ? necess?ria para identificar o agente etiol?gico e determinar a suscetibilidade aos antimicrobianos a fim de selecionar o f?rmaco ideal e limitar o desenvolvimento de resist?ncia, uma vez que bact?rias resistentes podem ser transmitidas entre animais e desses para o homem, como j? observado em isolados de Staphylococcus spp. resistentes ? oxacilina. O desenvolvimento de resist?ncia a azitromicina aponta para a necessidade de estudos que forne?am dados confi?veis a respeito do perfil de atividade desse f?rmaco de forma a contribuir na terap?utica veterin?ria sem causar impacto no desenvolvimento e dissemina??o de cepas resistentes.