A simple closed-loop membrane process for the purification of active pharmaceutical ingredients

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

Dissolution enhancement of active pharmaceutical ingredients by therapeutic deep eutectic systems

A therapeutic deep eutectic system (THEDES) is here defined as a deep eutectic solvent (DES) having an active pharmaceutical ingredient (API) as one of the components. In this work, THEDESs are proposed as enhanced transporters and delivery vehicles for bioactive molecules. THEDESs based on choline chloride (ChCl) or menthol conjugated with three different APIs, namely acetylsalicylic acid (AA), benzoic acid (BA) and phenylacetic acid (PA), were synthesized and characterized for thermal behaviour, structural features, dissolution rate and antibacterial activity. Differential scanning calorimetry and polarized optical microscopy showed that ChCl:PA (1:1), ChCl:AA (1:1), menthol:AA (3:1), menthol:BA (3:1), menthol:PA (2:1) and menthol:PA (3:1) were liquid at room temperature. Dissolution studies in PBS led to increased dissolution rates for the APIs when in the form of THEDES, compared to the API alone. The increase in dissolution rate was particularly noticeable for menthol-based THEDES. Antibacterial activity was assessed using both Gram-positive and Gram-negative model organisms. The results show that all the THEDESs retain the antibacterial activity of the API. Overall, our results highlight the great potential of THEDES as dissolution enhancers in the development of novel and more effective drug delivery systems.

Engineering Active Pharmaceutical Ingredients by Spray Drying: Effects on Physical Properties and In Vitro Dissolution

Active pharmaceutical ingredients have very strict quality requirements; minor changes in the physical and chemical properties of pharmaceuticals can adversely affect the dissolution rate and therefore the bioavailability of a given drug. Accordingly, the aim of the present study was to investigate the effect of spray drying on the physical and in vitro dissolution properties of four different active pharmaceutical ingredients, namely carbamazepine, indomethacin, piroxicam, and nifedipine. Each drug was dispersed in a solution of ethanol and water (70:30) and subjected to single-step spray drying using similar operational conditions. A complete characterization of the spray-dried drugs was performed via differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), particle size distribution analysis, solubility analysis, and an in vitro dissolution study. The results from the thermal analysis and X-ray diffraction showed that, except for carbamazepine, no chemical modifications occurred as a result of spray drying. Moreover, the particle size distribution of all the spray-dried drugs significantly decreased. In addition, SEM images showed that most of the particles had an irregular shape. There was no significant improvement in the solubility of the spray-dried drugs compared with the unprocessed compounds; however, in general, the dissolution rates of the spray-dried drugs showed a remarkable improvement over their non-spray-dried counterparts. Therefore, the results from this study demonstrate that a single spray-drying step may lead to changes in the physical properties and dissolution characteristics of drugs and thus improve their therapeutic action.

Development of novel active pharmaceutical ionic liquids and salts based on antibiotics and anti-fungal drugs

Ionic Liquids (ILs) are class of compounds, which have become popular since the mid-1990s. Despite the fact that ILs are defined by one physical property (melting point), many of the potential applications are now related to their biological properties. The use of a drug as a liquid can avoid some problems related to polymorphism which can influence a drug´s solubility and thus its dosages. Also, the arrangement of the anion or cation with a specific drug might be relevant in order to: a) change the correspondent biopharmaceutical drug classification system; b) for the drug formulation process and c) the change the Active Pharmaceutical Ingredients’ (APIs). The main goal of this Thesis is the synthesis and study of physicochemical and biological properties of ILs as APIs from beta-lactam antibiotics (ampicillin, penicillin G and amoxicillin) and from the anti-fungal Amphotericin B. All the APIs used here were neutralized in a buffer appropriate hydroxide cations. The cation hydroxide was obtained on Amberlite resin (in the OH form) in order to exchange halides. The biological studies of these new compounds were made using techniques like the micro dilution and colorimetric methods. Overall a total of 19 new ILs were synthesised (6 ILs based on ampicillin, 4 ILs, based on amoxicillin, 6 ILs based on penicillin G and 4 ILs based on amphotericin B) and characterized by spectroscopic and analytical methods in order to confirm their structure and purity. The study of the biological properties of the synthesised ILs showed that some have antimicrobial activity against bacteria and yeast cells, even in resistant bacteria. Also this work allowed to show that ILs based on ampicillin could be used as anti-tumour agents. This proves that with a careful selection of the organic cation, it is possible to provoke important physico-chemical and biological alteration in the properties of ILs-APIs with great impact, having in mind their applications.

Quality control of pharmaceutical ingredients:developing a caking test for industry

Objectives - Powdered and granulated particulate materials make up most of the ingredients of pharmaceuticals and are often at risk of undergoing unwanted agglomeration, or caking, during transport or storage. This is particularly acute when bulk powders are exposed to extreme swings in temperature and relative humidity, which is now common as drugs are produced and administered in increasingly hostile climates and are stored for longer periods of time prior to use. This study explores the possibility of using a uniaxial unconfined compression test to compare the strength of caked agglomerates exposed to different temperatures and relative humidities. This is part of a longer-term study to construct a protocol to predict the caking tendency of a new bulk material from individual particle properties. The main challenge is to develop techniques that provide repeatable results yet are presented simply enough to be useful to a wide range of industries. Methods - Powdered sucrose, a major pharmaceutical ingredient, was poured into a split die and exposed to high and low relative humidity cycles at room temperature. The typical ranges were 20–30% for the lower value and 70–80% for the higher value. The outer die casing was then removed and the resultant agglomerate was subjected to an unconfined compression test using a plunger fitted to a Zwick compression tester. The force against displacement was logged so that the dynamics of failure as well as the failure load of the sample could be recorded. The experimental matrix included varying the number of cycles, the amount between the maximum and minimum relative humidity, the height and diameters of the samples, the number of cycles and the particle size. Results - Trends showed that the tensile strength of the agglomerates increased with the number of cycles and also with the more extreme swings in relative humidity. This agrees with previous work on alternative methods of measuring the tensile strength of sugar agglomerates formed from humidity cycling (Leaper et al 2003). Conclusions - The results show that at the very least the uniaxial tester is a good comparative tester to examine the caking tendency of powdered materials, with a simple arrangement and operation that are compatible with the requirements of industry. However, further work is required to continue to optimize the height/ diameter ratio during tests.

Cromatografia preparativa: caracterização e purificação de produtos e impurezas com aplicação na indústria de APIs

Neste trabalho efectuou-se o desenvolvimento de métodos de purificação de princípios activos farmacêuticos utilizando a cromatografia preparativa em coluna (eluição batch). Por motivos de confidencialidade as amostras tiveram a denominação de Amostra Projecto A, Amostra Projecto B, Amostra Projecto C e Amostra 2 - Projecto A. Estudou-se a performance de coluna para cada projecto utilizando colunas pré-preparadas e colunas preparadas com a tecnologia DAC (Dynamical Axial Compression). Elaborou-se o procedimento experimental de enchimento de colunas preparativas sob compressão axial. As impurezas isoladas por cromatografia preparativa foram sujeitas a caracterização HPLC e LC-MS. Com colunas pré-preparadas, obteve-se para a amostra do projecto A um rendimento de 70,59% e relativamente à amostra projecto B obteve-se u, rendimento de 15,39%. Relativamente à impureza isolada da amostra do projecto A, o estudo por HPLC revelou 98,69% de pureza, quanto à impureza da amostra projecto B obteve-se 88,80% de pureza. A impureza da amostra do projecto A exibiu por LC-MS a massa de 467,15 enquanto que a impureza da amostra do projecto B obteve 503,31. O enchimento de colunas preparativas sob pressão axial dinâmica foi realizado numa coluna de dimensão 260 X 25 mm, onde 76,60% da coluna foi compactada com o material de enchimento SepTech ST150-C18, 10 µm. A coluna foi testada com a impureza isolada do projecto A. Isolou-se o pico referente à impureza, e por LC-MS verificou-se que a impureza foi isolada eficientemente com 97,20& de pureza e massa 467,15 como indicado anteriormente. Em relação à preparação de colunas com a tecnologia DAC concluímos que, neste caso, é mais vantajoso realizar o enchimento das colunas do que efectuar a compra de colunas pré-preparadas. Com estes resultados pode-se concluir que a cromatografia preparativa é um método eficaz no isolamento de impurezas de APIs (Active Pharmaceutical Ingredients) face a métodos de purificação clássicos que foram realizados previamente noutros estudos. Com futuros desenvolvimentos e investimentos, facilmente poderá tornar-se num método de purificação indispensável na Indústria de Química Fina.

Development of novel ionic liquids based on valproate anion

Valproic acid (2-propyl pentanoic acid) is a pharmaceutical drug used for treatment of epileptic seizures absence, tonic-clonic (grand mal), complex partial seizures, and mania in bipolar disorder [1]. Valproic acid is a slightly soluble in water and therefore as active pharmaceutical ingredient it is most commonly applied in form of sodium or magnesium valproate salt [1].However the list of adverse effects of these compounds is large and includes among others: tiredness, tremor, sedation and gastrointestinal disturbances [2]. Ionic liquids (ILs) are promising compounds as Active Pharmaceutical Ingredients (APIs)[3]. In this context, the combinations of the valproate anion with appropriate cation when ILs and salts are formed can significantly alter valproate physical, chemical and thermal properties.[4] This methodology can be used for drug modification (alteration of drug solubility in water, lipids, bioavailability, etc)[2] and therefore can eliminate some adverse effect of the drugs related to drug toxicity due for example to its solubility in water and lipids (interaction with intestines). Herein, we will discuss the development of ILs based on valproate anion (Figure 1) prepared according a recent optimized and sustainable acid-base neutralization method [4]. The organic cations such as cetylpyridinium, choline and imidazolium structures were selected based on their biocompatibility and recent applications in pharmacy [3]. All novel API-ILs based on valproate have been studied in terms of their physical, chemical (viscosity, density, solubility) and thermal (calorimetric studies) properties as well as their biological activity.

Synthesis, characterization and antiproliferative activity on cancer cell lines of new ionic liquids from ampicillin

Ionic Liquids (ILs) are ionic compounds that possess melting temperature below 100ºC and they have been a topic of great interest since the mid-1990s due to their unique properties. The range of IL uses has been broadened, due to a significant increase in the variety of physical, chemical and biological ILs properties. They are now used as Active Pharmaceutical Ingredients (APIs) and recent interests are focused on their application as innovative solutions in new medical treatment and delivery options.1 In this work, our principal objective was the synthesis and investigation of physicochemical and medical properties of ionic liquids (ILs) and organic salts from ampicillin. This approach is of huge interest in pharmaceutical industry as cation and anion composition of ILs and organic salts can greatly alter their desired properties, namely the melting temperature and even synergistic effects can be obtained.2,3 For the synthesis of these compounds we used a recently developed method proposed by Ohno et al.4 for the preparation of quaternary ammonium and phosphonium hydroxides, that were neutralized by ampicillin. After purification we obtained pure ILs and salts in good yields. These ILs shows good antimicrobial and antifungal activities. As it is well known that some ionic liquids containing phosphonium and ammonium cation also shows anti-cancer activity1,5 we also decided to study these compounds against some cancer cell lines.

QuEChERS: a new sample preparation approach for the determination of ibuprofen and its metabolites in soils

Ibuprofen is one of the most used active pharmaceutical ingredients worldwide. A new method for the analysis of ibuprofen and its metabolites, hydroxyibuprofen and carboxyibuprofen, in soils is presented. The extraction of these compounds from the soil matrices was performed by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. The method involves a single extraction of the investigated compounds with purified water (acidified at pH 2.5 with hydrochloric acid), and a slow and continuous addition of the QuEChERS content, followed by the addition of acidified acetonitrile (1% acetic acid), prior to the determination by liquid chromatography coupled with fluorescence detection (LC–FLD). Validation studies were carried out using soil samples with a range of organic carbon contents. Recoveries of the fortified samples ranged from 79.5% to 101%. Relative standard deviations for all matrix–compound combinations did not exceed 3%. The method quantification limits were ≤22.4 μg kg−1 in all cases. The developed method was applied to the analysis of sixteen real samples.

Evaluation of solubility and partition properties of ampicillin-based ionic liquids

In order to overcome the problems associated with low water solubility, and consequently low bioavailability of active pharmaceutical ingredients (APIs), herein we explore a modular ionic liquid synthetic strategy for improved APIs. Ionic liquids containing l-ampicillin as active pharmaceutical ingredient anion were prepared using the methodology developed in our previous work, using organic cations selected from substituted ammonium, phosphonium, pyridinium and methylimidazolium salts, with the intent of enhancing the solubility and bioavailability of l-ampicillin forms. In order to evaluate important properties of the synthesized API-ILs, the water solubility at 25 °C and 37 °C (body temperature) as well as octanol–water partition coefficients (Kow's) and HDPC micelles partition at 25 °C were measured. Critical micelle concentrations (CMC's) in water at 25 °C and 37 °C of the pharmaceutical ionic liquids bearing cations with surfactant properties were also determined from ionic conductivity measurements.

Síntese e caracterização de redes metalo-orgânicas de fármacos

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica

Bioatividade de Líquidos Iónicos derivados do Ácido Valpróico em bactérias Gram-negativa

Os Líquidos Iónicos (LIs) são sais orgânicos constituídos exclusivamente por iões e possuem pontos de fusão inferiores a 100ºC. As suas propriedades únicas e o facto de ser possível ajustar as suas propriedades físicas, químicas e biológicas, de acordo com o objetivo pretendido, tornam esta classe de compostos, um grande objeto de estudo de inúmeros investigadores. Desde os inícios da sua aplicação até à atualidade, a investigação nesta área expandiu o seu raio de ação, estando já descrito o seu potencial como agentes antimicrobianos e, mais recentemente, como compostos farmacêuticos ativos. Atualmente muitas das suas aplicações são baseadas nas suas propriedades biológicas. Esta Tese teve como objetivo avaliar a influência que os LIs podem exercer a nível do crescimento bacteriano e estudar alternativas de combater a resistência bacteriana. Todos os LIs utilizados neste trabalho tinham como anião o ácido valpróico, sendo utilizados catiões orgânicos de amónio e de imidazólio. Foram utilizadas 4 bactérias e avaliou-se a atividade biológica e a respetiva taxa de crescimento. O estudo da sua atividade biológica foi feito através da determinação da Concentração Mínima Inibitória (CMI) e a análise das suas curvas de crescimentos na presença e ausência de composto. Com este trabalho foi possível verificar que dentro dos compostos em estudo, LIs derivados do valproato, o Valproato com o cetilperidínio [valp] [cetylpir] foi o que influenciou o crescimento de todas as bactérias estudadas. Este estudo demonstrou o potencial antibacteriano de alguns compostos, podendo desta forma vir a ser utilizados para fins farmacêuticos

Development of electrospun Ion jelly fibers® for drug delivery

Dissertação para obtenção do Grau de Mestre em Biotecnologia

Application of OSN in membrane cascade for purification of the API Amoxicillin

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

Development of composite particles for pulmonary delivery

In this work, biocompatible and biodegradable poly(D-L-lactide-co-glycolide) (PLGA) microparticles with the potential for use as a controlled release system of vaccines and other drugs to the lung were manufactured using supercritical CO2, through the Supercritical Assisted Atomization (SAA) technique. After performing a controlled variance in production parameters (temperature, pressure, CO2/solution flow ratio) PLGA microparticles were characterized and later used to encapsulate active pharmaceutical ingredients (API). Bovine serum albumin (BSA) was chosen as model protein and vaccine, while sildenafil was the chosen drug to treat pulmonary artery hypertension and their effect on the particles characteristics was evaluated. All the produced formulations were characterized in relation to their morphology (Morphologi G3 and scanning electronic microscopy (SEM)), to their physical-chemical properties (X-ray diffraction (XRD, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR)) and aerodynamic performance using an in vitro aerosolization study – Andersen cascade impactor (ACI) - to obtain data such as the fine particle fraction (FPF) and the mass median aerodynamic diameter (MMAD). Furthermore, pharmacokinetic, biodegradability and biocompatibility tests were performed in order to verify the particle suitability for inhalation. The resulting particles showed aerodynamic diameters between the 3 and 5 μm, yields up to 58% and FPF percentages rounding the 30%. Taken as a whole, the produced microparticles do present the necessary requests to make them appropriate for pulmonary delivery.