In vitro evaluation of nanocomposites of linseed mucilage and k-carrageenan loaded with Achyrocline satureioides nanoemulsion: a gradual-release candidate of antimicrobials for the treatment of bovine mastitis.

This research paper presents the development and evaluation of pioneering nanocomposites (NCs) based on the combination of k-carrageenan and linseed mucilage. When loaded with macela extract nanoemulsion they present an innovative approach for the sustained release of antimicrobial herbal constituents, specifically tailored for bovine mastitis treatment. The NCs, encompassing various ratios of k-carrageenan and linseed mucilage polymers (8:2, 7:3, and 5:5 w/w) with 1.25 mg of macela extract/g of gel, underwent in vitro assessment, emphasizing viscosity, degradation speed, release of herbal actives from macela nanoemulsion and antimicrobial activity. The NCs exhibited thermoreversible characteristics, transitioning from liquid at 60°C to a gel at 25°C. NCs allowed a gradual release of phenolic compounds, reaching approximately 80% of total phenolics release (w/v) within 72 h. NCs inhibited the growth of MRSA (ATCC 33592) until 8 h of incubation. No toxic effect in vitro of NCs was found on MAC-T cells. Thus, the developed materials are relevant for the treatment of bovine mastitis, especially in the dry period, and the data support future evaluations in vivo.

A New Saquinavir Mesylate-Sodium Decyl Sulfate Salt Discovered by Serendipity during an Anomalous Dissolution Test.

PURPOSE: To understand the anomalous behavior of Saquinavir Mesylate (SQVM) in sodium decyl sulfate (SDS) medium during a dissolution test through a crystallographic analysis of the crystal obtained. As a result, it will be possible to elucidate its crystal structure and carry out a complete solid-state characterization of the API. METHODS: The solid form obtained was characterized by a structural analysis through X-ray single crystal and powder diffraction. The crystallographic structures of the new salt and the SQVM were compared. In addition, a complete solid-state characterization of SQVM raw material was carried out by techniques such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Raman spectroscopy, scanning electron microscopy and a dissolution method. RESULTS: A new salt consisting of SQVM and SDS was crystallized and its crystal structure was elucidated and reported herein for the first time. The anionic part of SDS interacts with the cationic segment of SQVM to obtain a new salt designated as SQV-DS, which precipitates. The main difference between the two structures occurs in the c-axis expansion, which increases from 15.966 (5) to 21.1924 (14), respectively. CONCLUSIONS: Some of the strategies to enhance the dissolution rate of poorly aqueous soluble APIs include the use of surfactants such as SDS in the dissolution medium, as well as in the formulated products. However, there have been constant reports of a dissolution rate slowdown by some surfactants. The interaction mechanisms between the APIs and the dissolution medium containing surfactants need to be carefully investigated in current pharmaceutical formulations. Graphical Abstract.

Comparator product issues for biowaiver implementation: the case of Fluconazole

The aim of this work was to assess if the commercially available Fluconazole drug products (Reference, Generic and Similar) would meet the biowaiver criteria from Food and Drug Administration (FDA) and Brazilian Agency for Health Surveillance (ANVISA) agencies. All formulations were evaluated considering the dissolution profile carried out in Simulated Gastric Fluid (SGF) pH 1.2, Acetate Buffer (AB) pH 4.5 and Simulated Intestinal Fluid (SIF) pH 6.8. The results demonstrated that all formulations fulfilled the 85% of drug dissolved at 30 min criterion in SGF pH 1.2. However, in AB pH 4.5 and SIF pH 6.8, some formulations, including the comparator, did not achieve this dissolution percentage. The discrepant dissolution profiles also failed the ƒ2 similarity factor analysis, since none of the formulations showed values between 50 and 100 in the three dissolution media. Comparative dissolution profiles were not similar, considering that the main issues concerning the dissolution were evidenced for the comparator product. Hence, a revision in the regulatory norms in order to establish criteria to switch the comparator could result in an increased application of drugs based on biowaiver criteria

Liquisolid Pellets and Liqui-Pellets Are Not Different.

Our research group has pioneered the development of liquisolid pellets as a new drug delivery system targeting at the improvement of the dissolution rates of poorly water-soluble drugs, combining the technological and biopharmaceutical advantages of both multiparticulate and liquisolid systems. Recently, Lam and collaborators claimed the invention of "liqui-pellets" as "the emerging next-generation oral dosage form which stems from liquisolid concept in combination with pelletization technology". However, the concept of liqui-pellet is not novel. As we demonstrate in this commentary, liqui-pellets are the same type of preparation as our previously and extensively reported liquisolid pellets. Liquisolid pellets have been disclosed in a patent application and public peer-reviewed articles covering the concept, preparation and challenges associated with these systems. There are no technical differences that justify excluding our previous reports as the first reports on liquisolid pellets or liqui-pellets. This commentary highlights the similarities between liquisolid pellets and liqui-pellets, focusing on the anteriority of liquisolid pellets as disclosed by our group.

Liquisolid pellets: A pharmaceutical technology strategy to improve the dissolution rate of ritonavir.

Liquisolid pellets (LPs) prepared by extrusion-spheronization are promising delivery systems to improve the dissolution rate of poorly water-soluble drugs. However, developing LPs for high dose drugs (e.g. antiretroviral ritonavir, RTV) is a major challenge due to technical and quality constraints. In this study, formulations LP1 and LP2 were obtained (RTV 100 mg/unit dose) using microcrystalline cellulose (carrier), Kollidon® CL-SF (coating and disintegrating material) and high load (30%, w/w) of Kolliphor® EL or PEG 400 (non-volatile solvent). LP1 and LP2 had narrow size distribution, good morphological properties, and excellent flowability. The partial conversion of RTV polymorph I to the less soluble form II occurred during the preparation of the liquid medications. LP1 (containing Kolliphor® EL) achieved 82.64 ±â€¯2.17% of drug dissolved in 30 min (Q30min), compared with 53.14 ±â€¯0.6% and 42.42 ±â€¯2.09% for LP2 (containing PEG 400) and Norvir® tablets, respectively. Also, LP1 promoted 1.9-fold/1.7-fold and 8.19-fold/8.29-fold increases in Q30min/DE60min (dissolution efficiency) as compared to neat RTV polymorphs I and II, respectively.

Chitosan microencapsulation of the dispersed phase of an O/W nanoemulsion to hydrochlorothiazide delivery.

In view of biopharmaceutical limitations of hydrochlorothiazide (HCTZ), Trojan-type mucoadhesive systems were proposed, aiming to improve HCTZ pharmacological properties by modulating its release. Nanoemulsions were formed spontaneously by combining medium-chain triglycerides (Lipoid® S75 and Pluronic® F68) and high encapsulation efficiency was obtained. The mucoadhesive properties were provided by chitosan and microencapsulation of nanoemulsions in spray-dryer was successfully achieved by using Aerosil® as wall material. The rapid redispersion of nanoemulsion in simulated fluids led to a fast and complete release of HCTZ in gastric medium. The pharmacodynamics of HCTZ was improved, extending the diuretic activity. Once a simple and low-energy method contributed to obtain stable mucoadhesive nanoemulsions, advantages in terms of production could also be achieved, allowing easy scaling up. This novel mucoadhesive Trojan particulate system of HCTZ showed to be a promising approach to overcome limitations in terms of absorption and consequently improve the therapeutic efficacy.

Self-Nanoemulsified Drug Delivery System of Hydrochlorothiazide for Increasing Dissolution Rate and Diuretic Activity.

Hydrochlorothiazide (HCTZ) is a class IV drug according to the Biopharmaceutical Classification System. This study aimed the development of self-nanoemulsifying drug delivery system (SNEDDS) for HCTZ as an approach to overcome the biopharmaceutical limitations. Pre-formulation screening and ternary phase diagrams were carried out to select the oil phase, the surfactant, and the co-surfactant as the amount of each constituent. The optimized formulations, with reduced amount of surfactant, and composed of medium chain triglycerides, Cremophor EL and Transcutol P did not affect the pH or show drug incompatibilities. The SNEDDS were stabilized by the nanoscale globules and high negative zeta potential. All the physicochemical characterization assays were performed in biorelevant media to better predict the in vivo performance. The enhanced dissolution rate of the SNEDDS reflected in the in vivo diuretic activity, presenting a natriuresis, kaliuresis, and chloriuresis at early stages and an increased volume of total urine compared with HCTZ alone. The designed SNEDDS produced an improvement in the pharmacodynamics due to high dissolution and probable inhibition of intestinal efflux protein by Cremophor EL. The use of SNEDDS demonstrated to be an efficient approach to modulate the absorption of HCTZ and drug therapeutics.

Lipid- and Polymer-Based Nanostructures for Cutaneous Delivery of Curcumin.

It is well-known that nanoencapsulation may overcome biopharmaceutical limitations of curcumin (CUR), but studies regarding the contribution of the vesicular nature of CUR-loaded nanoparticles on skin permeation are still scarce. Therefore, the effect of three colloidal systems (solid lipid nanoparticles (SLN), nanoemulsion (NE), and polymeric nanoparticles (NP)) on the control of cutaneous permeation of CUR was investigated in porcine ear skin/Franz diffusion cells. Colloidal suspensions were designed to present a similar particle size (±170 nm), narrow size distribution (PdI < 0.2), and high entrapment efficiency (>99%). Zeta potential values were -0.13, -9.68 and -36.7 mV for the CUR-loaded NP, SLN and NE, respectively. Nanoencapsulation resulted in a cumulative amount of CUR in the more superficial layers of the skin. NP significantly enhanced the compound retention in the epidermis, which was approximately 2.49- and 3.32-fold more than SLN and NE, respectively. The CUR levels into the dermis were significantly increased after treatment with NE, which may be associated with repulsion phenomena in surface skin. Therefore, a more superficial or deeper action of CUR on the skin may be obtained depending on nanostructure type. While NPs are more effective in upper skin layers, NE should be prioritized when a dermal action for the CUR is required.

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.

Investigation of ß-cyclodextrin-norfloxacin inclusion complexes. Part 2. Inclusion mode and stability studies.

INTRODUCTION: Norfloxacin (NFX) is a broad spectrum antibiotic with low solubility and permeability, which is unstable on exposure to light and humidity. OBJECTIVE: In this study, the mode of NFX inclusion into ß-cyclodextrin complexes was evaluated and a complete physical, chemical and microbiological stability study of the inclusion complexes was carried out. METHODS: Potentiometric titrations were performed to evaluate changes in the pKa of the NFX molecule due to the formation of an inclusion complex and NMR analysis demonstrated that the NFX molecule is included in the ß-cyclodextrin cavity. RESULTS: Inclusion complexes obtained by kneading followed by freeze-drying showed improved NFX stability compared with the isolated drug or the physical mixture. This method was effective in terms of protecting the drug from photodegradation and also avoiding hydrolysis. Differences between NFX and the complexes could be evidenced by thermal analysis, infrared spectroscopy and x-ray powder diffraction as well as by determining the solubility and drug content. The antimicrobial potency was also preserved on applying the promising method of kneading. CONCLUSION: The satisfactory stability indicates that the NFX/ß-cyclodextrin complexes could be useful as an alternative to the existing NFX drug formulation.

Pharmacodynamic and Pharmacokinetic Studies of β-Cyclodextrin:Dexamethasone Acetate Complexes in Mice

The aim of this study was to evaluate the in vivo activity of the anti-inflammatory and analgesic effects of a suspension of the complex composed of dexamethasone acetate (DMA) with β-cyclodextrin in comparison to a suspension of the pure DMA. Solid complexes prepared by different methods were evaluated in pharmacodynamics and pharmacokinetics studies. The pharmacodynamic effect was investigated although the capacity of the inhibited the inflammation. Models of abdominal constriction, carrageenan-induced paw oedema and formalin induced licking were used. The study of the pharmacodynamic comparison of free DMA and products of β-CD:DMA demonstrated no significant difference in the majority of the tests performed. Plasma concentrations of DMA and DMA:β-CD were assayed by HPLC. A significant (p > 0.05) decrease in the relative bioavailability was obtained with the suspension containing the DMA:β-CD complex as measured by DMA plasma levels. The area under the curve (AUC) of the suspension of DMA was higher than that obtained with the suspension of the complexes. The pharmacokinetic evaluation of dexamethasone carried out on mice in the present study showed that complexed DMA with β-cyclodextrin modifieds some parameters related to the phases of absorption and elimination of this drug.

Chitosan-decorated polystyrene-b-poly(acrylic acid) polymersomes as novel carriers for topical delivery of finasteride.

In view of the fact that the oral administration of finasteride (FIN) has resulted in various undesirable systemic side effects, the topical application of polystyrene and poly(acrylic acid)-based polymersomes (underexplored system) was investigated. Undecorated PS139-b-PAA17 and PS404-b-PAA63 vesicles (C3 and C7, respectively) or vesicles decorated with chitosan samples of different molecular weight (C3/CS-oligo, C7/CS-oligo, C3/CS-37 and C7/CS-37) were prepared by the co-solvent self-assembly method and characterized by small-angle X-ray scattering,transmission electron microscopy and dynamic light scattering techniques. In vitro release experiments and ex vivo permeation using Franz diffusion cells were carried out (through comparison with hydroethanolic finasteride solution). The ideal system should provide high finasteride retention in the dermis and epidermis while allowing some control of the drug release. The particle size and in vitro release were negatively correlated with the permeation coefficient and skin retention in both the epidermis and dermis. The findings that the longest lag time was obtained for the hydroethanolic drug solution and lowest permeation for the systems able to release the drug faster support the hypothesis that nanostructured systems may be required to enhance the penetration and permeation of the drug. Chitosan-decorated polymersomes interacted more strongly with the skin components than non-decorated samples, probably due to the positive surface charge, which increased the FIN retention and reduced the lag time. C7 polymersomes decorated with chitosan were more appropriate for topical applications (high retention in the dermis and epidermis and controlled drug delivery).

Formulation development and stability studies of norfloxacin extended-release matrix tablets.

The aim of this research was to develop a new hydrophilic matrix system containing norfloxacin (NFX). Extended-release tablets are usually intended for once-a-day administration with benefits to the patient and lower discontinuation of the therapy. Formulations were developed with hydroxypropylmethylcellulose or poly(ethylene oxide) as hydrophilic polymers, with different molecular weights (MWs) and concentrations (20 and 30%). The tablets were found to be stable (6 months at 40 ± 2°C and 75 ± 5% relative humidity), and the film-coating process is recommended to avoid NFX photodegradation. The dissolution profiles demonstrated an extended-release of NFX for all developed formulations. Dissolution curves analyzed using the Korsmeyer exponential equation showed that drug release was controlled by both drug diffusion and polymer relaxation or erosion mechanisms. A more erosion controlled system was obtained for the formulations containing lower MW and amount of polymer. With the increase in both MW and amount of polymer in the formulation, the gel layer became stronger, and the dissolution was more drug-diffusion dependent. Formulations containing intermediate MW polymers or high concentration (30%) of low MW polymers demonstrated a combination of extended and complete in vitro drug release. This way, these formulations could provide an increased bioavailability in vivo.

Nifedipine-loaded polymeric nanocapsules: validation of a stability-indicating HPLC method to evaluate the drug entrapment efficiency and in vitro release profiles.

A simple stability-indicating analytical method was developed and validated to quantify nifedipine in polymeric nanocapsule suspensions; an in vitro drug release study was then carried out. The analysis was performed using an RP C18 column, UV-Vis detection at 262 nm, and methanol-water (70 + 30, v/v) mobile phase at a flow rate of 1.2 mL/min. The method was validated in terms of specificity, linearity and range, LOQ, accuracy, precision, and robustness. The results obtained were within the acceptable ranges. The nanocapsules, made of poly(epsilon-caprolactone), were prepared by the solvent displacement technique and showed high entrapment efficiency. The entrapment efficiency was 97.6 and 98.2% for the nifedipine-loaded polymeric nanocapsules prepared from polyvinyl alcohol (PVA) and Pluronic F68 (PF68), respectively. The particle size and zeta potential of nanocapsules were found to be influenced by the nature of the stabilizer used. The mean diameter and zeta potential for nanocapsules with PVA and PF68 were 290.9 and 179.9 nm, and -17.7 mV and -32.7 mV, respectively. The two formulations prepared showed a drug release of up to 70% over 4 days. This behavior indicates the viability of this drug delivery system for use as a controlled-release system.

Estabilidade físico-química de formulações para nutrição parenteral neonatal manipuladas em hospital universitário / Physical and chemical stability of formulations for parenteral nutrition compounded at a university hospital

A estabilidade físico-química de três formulações para nutrição parenteral neonatal com diferentes quantidades de cátions bivalentes e de emulsão lipídica foi avaliada. As formulações foram analisadas nos tempos: 0, 24 e 48 horas, em três condições de temperatura diferentes de armazenamento: 2ºC-8ºC, 25ºC e 37ºC, mediante os seguintes parâmetros: pH, potencial zeta, tamanho e distribuição de partículas, microscopia óptica, propriedades reológicas, osmolaridade e aspecto visual. Os valores de pH mantiveram-se em todas as condições de estudo, em torno de 6,00 e os resultados de potencial zeta, em média, mostraram valores de - 27,65 mV. O tamanho das gotículas lipídicas apresentou-se constante e estável, em escala nanométrica, com gotículas não superiores a 5 μm em diâmetro. Os valores de viscosidade mantiveram-se constantes e os índices de fluxo apresentaram-se todos acima e próximos de 1,00. As osmolaridades teóricas apresentaram, em média, 822 mOsmol/L, todas inferiores ao limite máximo recomendado. Os sistemas emulsionados permaneceram visualmente estáveis e não foram notadas alterações de coloração, tampouco foram evidenciados processos de separação de fases nas formulações. Pode-se afirmar que as formulações apresentaram-se estáveis nas condições avaliadas. Demonstrou-se a necessidade e a importância da adoção de procedimentos de avaliação físico-química, somando-se ao controle microbiológico das formulações parenterais, para a garantia da eficácia da terapia e, principalmente, da segurança dessas formulações para os recém-nascidos.

The physical and chemical stability of three formulations for neonatal parental nutrition, made up with different amounts of divalent cations and lipid emulsion, were assessed. The formulations were analyzed at 0, 24 and 48 hours, under three different conditions of storage temperature: 2–8º C, 25º C and 37o C, in terms of the following parameters: pH, zeta potential, size and distribution of particles, optical microscopy, rheological properties, osmolarity and visual appearance. The pH remained, under all conditions studied, around 6.00 and the zeta potential was - 27.65 mV on average. The lipid droplet size was constant and stable, in the nanometer range, and no droplets exceeded 5 μm in diameter. The viscosities remained constant and all the flow behavior indices were above and close to 1.00. The theoretical osmolarities were, on average, 822 mOsmol/L, all below the recommended maximum value. The emulsion systems remained stable and there was no visually noticeable color change or evident phase separation in the formulations. It can be reported that all the formulations were stable under the conditions studied. The need and importance of adopting physicochemical evaluation procedures, in addition to the microbiological control of parental formulations, in order to guarantee the effectiveness of therapy, and especially the safety of these formulations for newborns, was demonstrated in this study.

Physicochemical and microbiological stability studies of extemporaneous antihypertensive pediatric suspensions for hospital use.

Extemporaneous suspensions of the antihypertensive agents furosemide, spironolactone and hydrochlorothiazide for pediatric use have been prepared at University Hospital (Federal University of Santa Catarina - Brazil). The aim of this work was to investigate the physicochemical and microbiological stability of these suspensions over the estimated shelf-life period of seven days and, if necessary, to optimize the formulations by improving the chemical stability. The pediatric suspensions were prepared using drug raw material and were stored at 25 ± 2°C and 5 ± 3°C. Chemical stability was evaluated by HPLC assay of the suspensions for drug content. Physical stability was evaluated by sedimentation volume, redispersibility, particle size, and zeta potential. Viable bacterial and fungal contaminations were assessed according to the official compendium. Furosemide and spironolactone suspensions as prepared herein can be stored for 7 days. However, the hydrochlorothiazide suspension formulation at pH 6.5 demonstrated poor chemical stability and was optimized by adjusting the pH to 3.3 where the drug exhibited acceptable stability. The optimized formulation demonstrated to be stable over the required period of 7 days.

Polymorphism in nimodipine raw materials: development and validation of a quantitative method through differential scanning calorimetry.

Due to the physical-chemical and therapeutic impacts of polymorphism, its monitoring in raw materials is necessary. The purpose of this study was to develop and validate a quantitative method to determine the polymorphic content of nimodipine (NMP) raw materials based on differential scanning calorimetry (DSC). The polymorphs required for the development of the method were characterized through DSC, X-ray powder diffraction (XRPD) and Raman spectroscopy and their polymorphic identity was confirmed. The developed method was found to be linear, robust, precise, accurate and specific. Three different samples obtained from distinct suppliers (NMP 1, NMP 2 and NMP 3) were firstly characterized through XRPD and DSC as polymorphic mixtures. The determination of their polymorphic identity revealed that all samples presented the Modification I (Mod I) or metastable form in greatest proportion. Since the commercial polymorph is Mod I, the polymorphic characteristic of the samples analyzed needs to be investigated. Thus, the proposed method provides a useful tool for the monitoring of the polymorphic content of NMP raw materials.

Spectrophotometric and HPLC determination of deflazacort in pharmaceutical dosage forms

Deflazacort (DFZ) is a glucocorticoid used as an anti-inflammatory and immunosuppressant drug. No official methods are available for DFZ determination in pharmaceutical formulations. The objective of this study was to develop, validate and compare spectrophotometric (UV and colorimetric) and high-performance liquid chromatography (HPLC) methods, for the quantitative determination of DFZ in tablets and oral suspension. For the UV method, ethanol was used as the solvent, with detection at 244 nm. The colorimetric method was based on the redox reaction with blue tetrazolium in alkaline medium, with detection at 524 nm. The method by HPLC was carried out using a C18 column, mobile phase consisting of acetonitrile:water (80:20, v/v) with a flow rate of 1.0 mL min-1 and detection at 244 nm. The methods proved linear (r > 0.999), precise (RSD < 5 percent) and accurate (recovery > 97 percent). Statistical analysis of the results indicated that the UV and HPLC methods were statistically equivalent, while the values obtained for the colorimetric method differed significantly from the other methods.

O deflazacorte (DFZ) é um fármaco glicocorticóide usado como antiinflamatório e imunossupressor. Métodos oficiais não estão disponíveis para a determinação de DFZ em formas farmacêuticas. Este estudo teve como objetivo desenvolver, validar e comparar métodos por espectrofotometria (UV e colorimetria) e cromatografia líquida de alta eficiência (CLAE), na determinação quantitativa de DFZ em comprimidos e suspensão oral. O método por UV utilizou etanol como solvente, com detecção em 244 nm. O método colorimétrico foi baseado na reação de redução com azul de tetrazólio em meio alcalino, com detecção em 524 nm. O método por CLAE utilizou coluna C18; fase móvel constituída de acetonitrila:água (80:20, v/v), com fluxo de 1,0 mL min-1 e detecção em 244 nm. Os métodos foram lineares (r > 0,999); precisos (RSD < 5 por cento), e exatos (recuperação > 97 por cento). As análises estatísticas dos resultados obtidos indicaram que os métodos por UV e por CLAE foram estatisticamente equivalentes, enquanto os valores obtidos para o método colorimétrico diferiram significativamente dos demais métodos.

Development of controlled release captopril granules coated with ethylcellulose and methylcellulose by fluid bed dryer.

Captopril granules of controlled release with different polymers as ethylcellulose, ethyl/methylcellulose, and immediate release with polyvinylpyrrolidone (PVP) were developed by fluid bed dryer technique. The formulations were analyzed by scanning electron microscopy, X-ray powder diffraction, and dissolution profiles. To compare the formulations an in vivo setting rat blood pressure assay was performed, using angiotensin I as a vasoconstrictor agent. The scanning electron microscopy of granules showed differences in morphology, and X-ray powder diffraction technique presented some modification in crystalline structure of captopril in granules coated with PVP and ethyl/methylcellulose. The dissolution profile of granules coated with ethylcellulose showed a median time release of 4 hr whereas for granules coated with ethyl/methylcellulose, this time was 3.5 hr. The blockage of angiotensin I-induced hypertensive effect lasted 8 hr in granules coated with PVP and of more than 12 hr in the granules coated with ethylcellulose and ethyl/methylcellulose.

Formas farmacêuticas sólidas orais de liberação prolongada: sistemas monolíticos e multiparticulados: [revisão] / Sustained release solid oral dosage forms: single-unity or multiple-unity systems: [review]

As formas farmacêuticas sólidas orais (FFSO) de liberação prolongada caracterizam-se pela liberação gradual do fármaco e manutenção da sua concentração plasmática em níveis terapêuticos, durante um período de tempo prolongado. Podem ser desenvolvidas como sistemas monolíticos ou multiparticulados, empregando-se tecnologias como matrizes poliméricas, sistemas reservatório ou bombas osmóticas. Este trabalho apresenta uma revisão acerca das tecnologias utilizadas para a obtenção de FFSO de liberação prolongada, destacando os benefícios tecnológicos e biofarmacotécnicos dos sistemas multiparticulados sobre os monolíticos. Os métodos empregados para a avaliação das características de dissolução desses sistemas são também abordados, especialmente o aparato 3 da Farmacopéia Americana. Por fim, são apresentados exemplos de produtos disponíveis no mercado brasileiro, com o objetivo de ilustrar a aplicabilidade das FFSO de liberação prolongada, além de verificar o perfil de utilização desses sistemas pela indústria nacional.

Sustained release solid oral dosage forms are characterized by the gradual release of the drug and maintenance of its plasmatic concentration in therapeutic levels, during a prolonged period of time. They can be designed as single-unity or multiple-unity dosage forms, using technologies such as matrix, reservoir or osmotic systems. The present work is a review on the technologies used to obtain sustained release oral dosage forms, with a special attention to the technological and biopharmaceutical benefits of multiple-unity over single-unity systems. The methods used in the evaluation of the dissolution characteristics of such systems are also approached. Examples of products available in the Brazilian market are shown with the purpose of illustrating the applicability of sustained release solid oral dosage forms, besides verifying the profile of utilization of these systems by the national industry.