Stability of sulfadiazine sugar-free oral suspensions for the treatment of congenital toxoplasmosis

Abstract This study aimed to develop and evaluate the stability of sulfadiazine sugar-free extemporaneous oral suspensions, focusing on treating congenital toxoplasmosis. The excipients were carefully chosen to obtain safe products for the pediatric population. Sulfadiazine suspensions (100 mg/ mL) were prepared from the raw material or tablets, stored in amber glass bottles at 5±3ºC, and evaluated at 0, 14, and 30 days. An ultra-performance liquid chromatographic method was developed and validated to assay the drug. The particle size ranged from 29.3 to 50.6 µm, with some variation over the study; pH values around 7.0 and non-Newtonian behavior were observed without modification in the period. Formulations showed a fast dissolution rate (>80% in 15 minutes) without variation over the study. The drug assay was about 100% of the label claimed throughout the study, demonstrating the chemical stability and the preparations' dose homogeneity. The microbiological investigation indicated that both preparations met the requirements for the microbial count and absence of pathogens. In conclusion, the developed formulations can be used for 30 days when stored under refrigeration. The oral suspensions produced are easy to prepare and contain safe components, providing an alternative for congenital toxoplasmosis treatment in children.

Development of a nanotechnological hydrogel containing desonide nanocapsules in association with acai oil: design and in vivo evaluation.

Nanotechnological products have been used as strategies to optimize the therapy and minimize the side effects of topical corticoids. The objective of this study was to develop hydrogels by the addition of sclerotium gum to the suspensions of desonide-loaded açai oil-based nanocapsules and to study their biological effect using an animal model of acute skin inflammation. The hydrogels presented a pH compatible with topical application (4.4 to 5.0), nanometric mean diameter (131 to 165 nm), pseudoplastic behavior, and stability under room conditions during 30 days. The in vitro skin permeation/penetration study demonstrated that a higher amount of desonide (p < 0.05) was retained in the epidermis from the nanotechnological-hydrogels (0.33 to 0.36 µg.cm2) in comparison to the commercial gel cream (0.16 µg.cm2). In the dermis, the nanostructured hydrogels promoted a lower DES retention compared to the non-nanostructured formulations (p < 0.05). This result may indicate a smaller amount of drug reaching the bloodstream and, thus, fewer side effects can be expected. Concerning the anti-inflammatory effect, the developed hydrogels reduced both ear edema and inflammatory cell infiltration, showing an effect comparable to the commercially available formulation, which presents twice the drug concentration. The hydrogels developed may be considered a promising approach to treat dermatological disorders.

Development of an HPLC-UV Method to Assay Empagliflozin Tablets and Identification of the Major Photoproduct by Quadrupole Time-of-Flight Mass Spectrometry.

Diabetes is a set of metabolic disorders that affect >400 million individuals worldwide. Empagliflozin belongs to the gliflozin class and is used orally to treat type 2 diabetes. In this study, a simple stability-indicating HPLC-UV method was developed to assay empagliflozin tablets and its main photoproduct was identified by high-resolution mass spectrometry. The mobile phase, which was optimized by Central Composite Design, was composed of methanol, acetonitrile and purified water (60:5:35 v/v), at a flow rate of 1 mL min-1. The calibration curve was linear in the range of 5-150 µg mL-1. All the validation parameters were met and the method was specific, even in the presence of degradation products. In the forced degradation study, empagliflozin standard and empagliflozin tablets were submitted to several conditions (acidic, alkaline, neutral and oxidant media, thermal, photolytic and humidity), and empagliflozin showed instability under all these conditions. A degradation product generated after drug exposure to ultraviolet C radiation was isolated and analyzed by quadrupole time-of-flight mass spectrometry, and the results suggested that empagliflozin undergoes decomposition by a dechlorination pathway. In silico toxicity was predicted for the degradation product, which showed a high risk of genotoxicity and hepatotoxicity.

Development of doxycycline hyclate suppositories and pharmacokinetic study in rabbits.

Doxycycline hiclate is a broad spectrum antibiotic widely used in human and veterinary medicine. The inability to perform the parenteral administration of drugs and the lack of oral preparations can be mentioned as difficulties in the treatment of animals in the domestic environment. In this scenario, the aim of this study was to investigate the bioavailability of the drug by rectal route, to propose a potential suppository formulation containing 25 mg of doxycycline as an alternative to the available injectable formulations. Hydrophilic and lipophilic suppositories were prepared, in polyethylene glycol (S-PEG) or cocoa butter (S-CBT), respectively. The suppositories were prepared and evaluated concerning visual characteristics, content, average weight, melting range, content uniformity and in vitro release. A stability study was performed and the two most stable formulations were submitted to a pharmacokinetic study in rabbits. The bioavailability of the suppositories was compared to the data of the intravenous (i.v.) formulation. PEG suppository showed 49.13% bioavailability and CBT 51.43% with Cmax equal to 2.06 ±â€¯2.96 µg.mL-1 and 1.54 ±â€¯0.28 µg.mL-1, respectively. The data obtained suggest that rectal administration may become another method of administration of doxycycline in the treatment of bacterial infections.

Desonide nanoencapsulation with açai oil as oil core: Physicochemical characterization, photostability study and in vitro phototoxicity evaluation.

This study aimed to develop Eudragit® RL 100 nanocapsules loaded with desonide (DES) using açai oil (AO) or medium chain triglycerides (MCT) as oil core. Pre-formulation study showed that AO and MCT are suitable for nanocapsules preparation. The nanocapsules prepared with AO and MCT presented mean particle size around 165 and 131 nm, respectively; polydispersity index values <0.20, positive zeta potential values, drug content close to the theoretical value (0.25 mg mL-1), and DES encapsulation efficiency around 81%, regardless of the oil core (AO or MCT). Considering the photoinstability reported to DES, photodegradation studies were performed. The UV-A (365 nm) and UV-C (254 nm) photodegradation studies revealed less DES degradation when associated to the nanocapsules containing AO in comparison to those with MCT. The in vitro release study showed a biphasic release profile for both nanocapsule suspensions: an initial burst effect followed by a prolonged DES release. In addition, the formulations were considered non-phototoxic at 0.5 mg mL-1 when tested on 3 T3 murine fibroblasts and HaCaT human keratinocytes using the MTT and NRU viability assays. The irritant potential of the prepared nanocapsules and DES in free form were evaluated by HET-CAM method. All formulations were classified as slightly irritant, including the non-associate DES. In conclusion, the nanocapsule formulations developed in this study may be promising for therapeutic applications.

Capillary zone electrophoresis method to assay tipranavir capsules and identification of oxidation product and organic impurity by quadrupole-time of flight mass spectrometry.

Tipranavir (TPV) is one of the most recently developed protease inhibitors (PI) and it is specially recommended for treatment-experienced patients who are resistant to other PI drugs. In this work, a simple and friendly environmental CZE stability-indicating method to assay TPV capsules was developed and two TPV organic impurities were identified by high resolution mass spectrometry (HRMS). The optimized analytical conditions were: background electrolyte composed of sodium borate 50mM, pH 9.0 and 5% of methanol; voltage + 28kV; hydrodynamic injection of 5s (100mbar), detection wavelength 240nm, at 25°C. The separation was achieved in a fused silica capillary with 50µm × 40cm (inner diameter × effective length), using furosemide as internal standard. All the validation parameters were met and the method was specific, even in the presence of degradation products and impurities. Oxidation was indicated as the main degradation pathway among those evaluated in this study (acidic, alkaline, thermal, photolytic and oxidative) and it showed a second order degradation kinetic, under the conditions used in this study. The main oxidation product and an organic impurity detected in the standard were characterized by Q-TOF, and both of them correspond to oxidation products of TPV.

In vitro and in vivo evaluation of a desonide gel-cream photostabilized with benzophenone-3.

CONTEXT: Our group previously reported the photoinstability of some desonide topical commercial formulations under direct exposure to UVA radiation. OBJECTIVE: This study aimed to prepare and characterize a gel-cream containing desonide, with greater photostability than the commercial gel-cream (C-GC). Benzophenone-3 (BP-3) was used as a photostabilizing agent. METHODS: The gel-cream developed (D-GC) containing BP-3 at 0.1% was prepared and characterized regarding its pH, drug content, spreadability, viscosity, in vitro drug release and in vitro permeation. The in vivo anti-inflammatory effect was assessed by ear edema measurement, croton oil-induced acute skin inflammation and myeloperoxidase assay. RESULTS AND DISCUSSION: D-GC presented characteristics compatible with topical application, appropriate drug content and good spreadability, and non-Newtonian behavior with pseudoplastic flow. D-GC showed a good photostability profile, presenting a desonide content of 95.70% after 48 h of exposure to UVA radiation, and stability under room conditions during 60 days. The amount of desonide released from D-GC and C-GC was 57.8 and 51.7 µg/cm2, respectively, measured using the vertical Franz cell. The in vitro skin permeation showed that desonide reached the site of action of the topical corticosteroids, from both formulations; however, the desonide amount retained in the dermis was lower with D-GC. The in vivo evaluation of topical anti-inflammatory activity indicated that D-GC presented the same biological effect as C-GC. CONCLUSION: D-GC represents a promising approach to treat dermatological disorders, since it presented satisfactory physicochemical characteristics, the same biological activity as C-GC and superior photostability, conferred by the addition of BP-3 at 0.1%.

A fully validated microbiological assay for daptomycin injection and comparison to HPLC method

abstract Daptomycin (DPT) was the first lipopeptide antibiotic available for commercialization. It is active against gram-positive bacteria, including resistant strains. This work aimed to develop and validate a turbidimetric microbiologic assay to determine daptomycin in an injectable form. A 3x3 design was employed, at concentrations of 1, 2 and 4.0 µg/mL. The microorganism test used was Staphylococcus aureus ATCC 6538p, and Antibiotic Medium 3 was used as the culture medium. Method validation demonstrated that the bioassay was linear (r=0.9995), precise (RSD=2.58%), accurate (recovery 100.48± 2.11%), and robust. Degradation kinetics was also performed in an alkaline medium, indicating that daptomycin degradation follows first order kinetics under these conditions. The analyses of degraded solutions showed that daptomycin degradation products do not possess bactericidal activity. The bioassay was compared to HPLC method that was previously developed and no significant difference was found between them (p>0.05). The method proved to be appropriate for daptomycin injection quality control.

resumo A daptomicina (DPT) é o primeiro lipopeptídeo cíclico disponível para comercialização. Possui atividade frente a bactérias gram-positivas, incluindo cepas resistentes. O objetivo deste trabalho foi desenvolver e validar um ensaio microbiológico turbidimétrico para quantificar a daptomicina na forma injetável. Empregou-se delineamento 3x3, nas concentrações de 1,0; 2,0 e 4,0 µg/mL. Como micro-organismo teste foi usado Staphylococcus aureus ATCC 6538p, e Meio para Antibióticos nº 3 foi empregado como meio de cultura. A validação do método demonstrou que o ensaio foi linear (r=0,9995), preciso (RSD=2,55%), exato (recuperação de 100,48 ± 2,11%) e robusto. A cinética de degradação em meio alcalino foi avaliada, indicando que a daptomicina segue cinética de primeira ordem nessa condição. A análise das soluções degradadas mostrou que os produtos de degradação da daptomicina não possuem atividade antimicrobiana. O bioensaio foi comparado com o método por CLAE previamente desenvolvido e não houve diferença significativa entre ambos (p<0,05). O método mostrou-se apropriado para o controle de qualidade da daptomicina injetável.

Stability indicating RP-LC-PDA method for the quantitative analysis of saxagliptin in pharmaceutical dosage form / Estabilidade indicando o método de RP-LC-PDA para a análise quantitativa de saxagliptina em forma de dosagem farmacêutica

Saxagliptin is a potent and selective inhibitor of the enzyme dipeptidyl peptidase 4. It is effective in the treatment of type 2 diabetes mellitus because it stimulates the pancreas to produce insulin. In the present study, a liquid chromatography method was developed and validated to quantify the drug in tablets. This method was based on the isocratic elution of saxagliptin, using a mobile phase consisting of 0.1% phosphoric acid at pH 3.0 - methanol (70: 30, v/v) at a flow rate of 1 mL.min^-1 with UV detection at 225 nm. The chromatographic separation was achieved in 8 minutes on a Waters XBridge C18 column (250 mm x 4.6 mm, 5µm) maintained at ambient temperature. The proposed method proved to be specific and robust for the quality control of saxagliptin in pharmaceutical dosage forms, showing good linearity in the range of 15.0 - 100.0 µg.mL^-1 (r>0.999), precision (RSD<1.49%) and accuracy values between 99.42 and 101.59%. The method was found to be stability indicating and was successfully applied for the analysis of saxagliptin in tablets in a routine quality control laboratory...

A saxagliptina é uma inibidora potente e seletiva da enzima dipeptidil peptidase 4. É efetiva no tratamento do Diabete mellitus tipo 2, pois estimula a produção de insulina pelo pâncreas. No presente estudo, desenvolveu-se e validou-se método por cromatografia líquida de alta eficiência para quantificar o fármaco em comprimidos. O método foi baseado em eluição isocrática, utilizando fase móvel constituída por ácido fosfórico 0,1% pH 3,0-metanol (70 : 30, v/v), fluxo de 1,0 mL.min^-1, com detecção UV em 225 nm. A separação cromatográfica foi alcançada em 8 minutos em coluna Waters XBridge C18 (250 mm x 4,6 mm, 5 µm) mantida à temperatura ambiente. O método proposto mostrou-se específico e robusto para o controle de qualidade de saxagliptina em comprimidos, sendo linear na faixa de concentração de 15,0-100,0 µg.mL^-1 (r>0,999), preciso (RSD<1,49%) e exato, com resultados entre 99,42 e 101,59%. O método mostrou-se indicativo de estabilidade e foi aplicado com sucesso no controle de qualidade de saxagliptina em comprimidos...

Investigation of ß-cyclodextrin-norfloxacin inclusion complexes. Part 1. Preparation, physicochemical and microbiological characterization.

INTRODUCTION: Drugs classified as class IV by the Biopharmaceutical Classification System present significant problems in relation to effective oral administration. In the case of antibiotics, the subsequently high doses required can enhance the emergence of microorganism resistance and lead to a low rate of patient treatment adherence. OBJECTIVE: In an attempt to improve physicochemical properties and microbiological activity of norfloxacin, the aim of this study was to investigate different methods (coevaporation, kneading followed by freeze-drying or spray-drying) to obtain complexes of norfloxacin and different cyclodextrins. METHODS: Guest-host interactions were investigated through a complete physical-chemical characterization and the dissolution profile and microbiological activity were determined. RESULTS: The formation of a complex of norfloxacin and ß-cyclodextrin (1:1), obtained by kneading followed by freeze drying, led to increased drug solubility, which could maximize the oral drug absorption. CONCLUSION: Moreover, the microbiological activity was enhanced by around 23.3%, demonstrating that the complex formed could represent an efficient drug delivery system.

Development and validation of a stability-indicating LC method for the assay of lodenafil carbonate in tablets.

A stability-indicating liquid chromatographic method has been developed for the quantitative determination of lodenafil carbonate in tablets. The method employs a Synergi Fusion C18 column (250 × 4.6 mm, i.d., 4 µm particle size), with mobile phase consisting of a mixture of methanol-acetic acid 0.1% pH 4.0 (65:35, v/v) and UV detection at 290 nm, using a photodiode array detector. A linear response (r = 0.9999) was observed in the range of 10-80 µg/mL. The method showed good recoveries (average 100.3%) and also intra and inter-day precision (RSD < 2.0%). Validation parameters as specificity and robustness were also determined. Specificity analysis showed that no impurities or degradation products were co-eluting with the lodenafil carbonate peak. The method was found to be stability-indicating and due to its simplicity and accuracy can be applied for routine quality control analysis of lodenafil carbonate in tablets.

Doseamento do cloridrato de sertralina por cromatografia líquida de alta eficiência e volumetria em meio não-aquoso / Sertraline hydrochloride assay by high performance liquid chromatography and nonaqueous titrimetry

Foram desenvolvidos métodos aplicando-se a volumetria em meio não-aquoso (VMNA) e a cromatografia líquida de alta eficiência (CLAE) para o doseamento do cloridrato de sertralina como matéria-prima, cápsulas e comprimidos. O método cromatográfico foi devidamente validado e, para tanto, empregou-se fase móvel composta por acetonitrila: tampão fosfato de sódio pH 5,5 (7:3), coluna RP-8 LiChrospher© 100, 5µm (125 mm x 4 mm), vazão de 1,0 mL/min e detecção no UV a 270nm. A taxa média de recuperação do método por CLAE aplicado às formulações foi de 99,18 porcento e os coeficientes de variação encontrados variaram entre 0,32 a 1,15 porcento (volumetria) e 0,19 a 1,04 porcento (CLAE). O método volumétrico apresentou...