Desenvolvimento de rota sintética da Rosiglitazona em processo batelada e microrreator capilar / Rosiglitazone synthetic route development in batch process and capillary microreactor

Para que os fármacos possam ser comercializados economicamente, a sua escala de produção deve ser aumentada para atender à demanda do mercado. Atualmente, a maior parte dos fármacos são sintetizados em processos batelada que possuem limitações quanto à eficiência de mistura, temperatura e pressão. O uso de microrreatores surge como alternativa na indústria químico-farmacêutica, aumentando a eficiência dos processos de maneira segura. Ferramentas utilizadas no segmento computacional multidisciplinar teórico, como o DFT (Density Functional Theory), podem prever e compreender o comportamento das reações químicas, podendo ter grande utilidade na síntese de novos fármacos economizando tempo, investimento e reduzindo a geração de resíduos. A diabetes mellitus é uma doença de caráter epidêmico, que a cada ano vem aumentando o número de casos. O emprego de fármacos derivados das glitazonas no tratamento de diabetes mellitus tipo 2 é recomendado devido ao excelente controle glicêmico que esta classe de fármacos oferece. Neste trabalho, foi sintetizada a Rosiglitazona, um fármaco derivado das glitazonas, que auxilia no tratamento da diabetes mellitus tipo 2, sendo estudadas duas rotas de síntese distintas, que foram otimizadas com o intuito de maximizar o rendimento de seus intermediários, obtendo a Rosiglitazona com pureza de cerca de 94%. Foi realizada, para os intermediários, aqui denominados, 1R, 2R2 e 3R2 a síntese one-pot e para os intermediários 1R, 2R1 e 3R2 foi realizada a transposição do processo usual em batelada para fluxo contínuo no microrreator, com rendimentos de até 93%. Com o auxílio da química quântica computacional, a reação de síntese do intermediário 1R, foi elucidada teoricamente e determinadas as grandezas termodinâmicas (ΔH‡, ΔG‡ e ΔS‡) no estado de transição, que foram comparadas com os valores experimentais, sendo constatada uma boa concordância, com desvio máximo de 14%

In order for drugs to be commercialized economically, their production scale must be increased to meet market demand. Currently, most drugs are synthesized in batch processes that have limitations in terms of mixing efficiency, temperature and pressure. The use of microreactors appears as an alternative in the chemical-pharmaceutical industry, increasing the efficiency of the synthesis processes in a safe way. Tools used in the theoretical multidisciplinary computational segment, such as DFT (Density Functional Theory), can predict and understand the behavior of chemical reactions, and can be very useful in the synthesis of new drugs, saving time, investment and reducing waste generation. Diabetes mellitus is an epidemic disease that has been increasing the number of cases every year. The use of drugs derived from glitazones in the treatment of type 2 diabetes mellitus is recommended due to the excellent glycemic control that this class of drugs offers. In this work, Rosiglitazone, a drug derived from glitazones, which helps in the treatment of type 2 diabetes mellitus, was synthesized. Two different synthetic routes were studied and optimized in order to maximize the yield of its intermediates, obtaining Rosiglitazone with purity of about 94%. One-pot synthesis was performed to 1R, 2R2 and 3R2 intermediates, and the transposition from the usual batch process to continuous flow in microreactor was performed to 1R, 2R1 and 3R2 intermediates, with yields of up to 93%. With the aid of computational quantum chemistry, the intermediate 1R synthesis reaction was theoretically elucidated and the thermodynamic properties were determined (ΔH‡, ΔG‡ and ΔS‡) in the transition state, which were compared with the experimental results, obtaining good agreement, with a maximum deviation of 14%

Decline in Public Spending on Biopharmaceutics in Brazil

Abstract Biopharmaceuticals, mainly monoclonal antibodies, and fusion proteins are drugs that have gained notoriety in the treatment of various chronic and inflammatory diseases and have high prices. The study aimed to verify which monoclonal antibodies and fusion proteins were most incorporated into the Unified Health System (SUS), which therapeutic indication most benefited from them and to analyze public spending on these biopharmaceuticals from January 2012 to September 2019. This study performed a qualitative and quantitative analysis of biopharmaceuticals incorporated by SUS. The data were collected on the websites of CONITEC and the Health Price Bank. The results demonstrated that subcutaneous adalimumab was most frequently incorporated, and the most requested therapeutic indication was rheumatoid arthritis. Public spending on biopharmaceuticals exceeded R$ 28 billion (more than US$ 140 billion). However, a downward trend was confirmed (-266.7%) in the period evaluated. Despite the increase in demand and public spending on biologics in general, in Brazil and worldwide, the results of this research show that there was a drop in public spending on the biopharmaceuticals studied in the last seven years.

Erding formula and bioactive markers in hyperuricemia: towards rational scientific approaches for the modernization of Traditional Chinese Medicine

Introduction: Traditional Chinese Medicine (TCM) represents one of the first holistic approaches in the world to treat and prevent disease. Herbal medicine is one of the major therapeutic remedy in TCM. It often involves multi-herb therapies instead of single herb preparations. Parallel to western medicine, hundreds of herbal formulas have been made available as finished products. Currently, the use of herbal products is popular as treatment option or to complement western medicine. Indications of the herbal formulas were established by TCM terms such as heat-clearing and/or detoxifying which lack modern pharmacological meanings. It is difficult for people without relevant background to understand such terms and their implications for treatments. Furthermore, due to the quality control issues of herbal medicines which contain multiple constituents, consumers may be confronted with the risk of using unstandardized products. Hence, in this thesis, the modernization of TCM is discussed through employing scientific pharmaceutical approaches to a traditional formula, called Erding formula (EF). The aim was to investigate if a new indication, hyperuricemia, can be assigned to a heat-clearing and detoxifying formula. Our hypothesis was: Can Erding formula be used for hyperuricemia treatment and is esculetin a bioactive marker for this new indication? Methods: A hypoxanthine and potassium oxonateinduced hyperuricemic mouse model, a xyleneinduced inflammatory mouse model, and an acetic acidinduced pain model were used to investigate EF and its constituent herbs. The quantity of esculetin was measured by high-performance liquid chromatography. The therapeutic effect of esculetin was assessed using potassium oxonate induced hyperuricemic mouse model, and esculetin and its metabolites were characterized in serum via ultra-performance liquid chromatographyquadrupole time-of-flight mass spectrometry. To develop a modern dosage form, a laboratory-scale wet bead milling approach was employed to prepare esculetin nanocrystals. The formulation was further optimized by design of experiment, and an optimized formulation was then characterized for its saturation solubility and short-term stability. Results: The study showed that EF and Viola yedoensis Makino (Viola) lowered uric acid (UA) levels, while EF and all four individual herbs had antiinflammatory and analgesic activities. These findings revealed that EF was able to treat hyperuricemia and suggested that Viola was the main herb in EF on reducing UA levels. The study showed that esculetin significantly reduced UA levels and six metabolites of esculetin were identified in serum. This confirms that esculetin was absorbed and is a suitable bioactive and quality control marker for EF in hyperuricemia treatment. An esculetin-Povacoat nanocrystal formulation with a 200 nm particle size was successfully prepared. The formulation presented up to a 1.5-fold increase in saturation solubility compared to the bulk esculetin and it was stable for 180 days. Conclusion: The studies proved that Erding formula can be used for hyperuricemia treatment with esculetin as bioactive quality control marker. As well, a new nano-sized formulation of the bioactive marker, esculetin, was created. This presented the possibility to develop an innovative nanotechnological product of the active substances derived from herbal medicine. The findings facilitated a better understanding of TCM terms and concept through mechanistic scientific experiments. This study revealed a potential pathway and an idea to modernize TCM without setting aside its unique concepts. This might increase the global acceptance of TCM products. Furthermore, the TCM concept might be useful in the development of multi-component drug products

Medicina Tradicional Chinesa (MTC) representa uma das primeiras abordagens holísticas em âmbito global para tratar e prevenir doenças. A fitoterapia consiste na principal terapia na MTC. Frequentemente, envolve terapias com múltiplas ervas em vez de preparações individuais. Paralelamente à medicina ocidental, centenas de fórmulas herbais foram disponibilizadas como produtos acabados. Atualmente, o uso de produtos fitoterápicos é popular como opção de tratamento ou para complementar a medicina ocidental. As indicações das fórmulas fitoterápicas foram estabelecidas pelos termos da MTC, tais como "limpeza pelo calor e / ou desintoxicante", que não têm significados farmacológicos modernos. É difícil para a população em geral e mesmo para profissionais sem histórico relevante na área entender tais termos e suas implicações para os tratamentos. Além disso, devido às questões de controle de qualidade dos medicamentos fitoterápicos que contêm múltiplos constituintes, os pacientes podem ser confrontados com o risco de usar produtos não padronizados. Assim, nessa tese, a modernização da MTC é discutida por meio da utilização de abordagens farmacêuticas científicas para uma fórmula tradicional, denominada fórmula de Erding (FE). O objetivo foi o de investigar se uma nova indicação, a hiperuricemia, pode ser atribuída a uma fórmula desintoxicante e de compensação de calor. Nossa hipótese foi: a fórmula de Erding pode ser usada para tratamento de hiperuricemia e a esculetina é um marcador bioativo para essa nova indicação? Foi empregado modelo de camundongo hiperuricêmico induzido por hipoxantina e oxonato de potássio, outro modelo de camundongo inflamatório induzido por xileno e, adicionalmente, modelo de dor induzida por ácido acético. Esses modelos foram usados para investigar a FE e suas ervas constituintes. A quantidade de esculetina foi determinada por cromatografia líquida de alta eficiência. O efeito terapêutico da esculetina foi avaliado utilizando modelo de camundongo hiperuricêmico induzido por oxonato de potássio, e a esculetina e seus metabólitos foram caracterizados no soro por cromatografia líquida de alto desempenho - espectrometria de massa. Para desenvolver forma farmacêutica moderna, uma abordagem de moagem em escala úmida reduzida foi empregada tendo em vista a preparação de nanocristais de esculetina. A formulação foi ainda otimizada empregado planejamento experimental. Essa fórmula foi caracterizada quanto à sua solubilidade de saturação e estabilidade a curto prazo. O estudo mostrou que a FE e a Viola yedoensis Makino (Viola) reduziram os níveis de ácido úrico (AU), enquanto a FE e as quatro plantas individuais apresentaram atividades antiinflamatória e analgésica. Esses resultados revelaram que a FE foi capaz de tratar a hiperuricemia e sugeriu que a viola foi a principal erva da FE na redução dos níveis de AU. O estudo mostrou também que a esculetina reduziu significativamente os níveis de AU e os seis metabólitos da esculetina foram identificados no soro. Tal resultado confirma que a esculetina foi absorvida e pode ser usada como marcador de controle bioativo e de qualidade para FE, no tratamento da hiperuricemia. A formulação de nanocristais de esculetin-povacoat® apresentou tamanho de partícula de 200 nm. A formulação apresentou aumento de 1,5 vezes na solubilidade de saturação em comparação com a esculetina em escala micrométrica e manteve-se estável durante 180 dias. Os estudos comprovaram que a fórmula de Erding pode ser utilizada no tratamento da hiperuricemia empregando a esculetina como marcador bioativo de controle de qualidade. Além disso, foi desenvolvida formulação inovadora, em escala nanométrica, do marcador bioativo, a esculetina. Esse resultado permitiu desenvolver produto com base nanotecnológica das substâncias ativas derivadas do fitoterápico, assim comol permitiram melhor compreensão dos termos e dos conceitos da MTC por meio de experimentos científicos mecanicistas. Esse estudo revelou potencial para a modernização da MTC sem excluir seus conceitos únicos. Isso pode aumentar a aceitação global dos produtos MTC. Além disso, o conceito de MTC pode ser útil no desenvolvimento de medicamentos de múltiplos componentes

Investigating Halloysite Nanotubes as a Potential Platform for Oral Modified Delivery of Different BCS Class Drugs: Characterization, Optimization, and Evaluation of Drug Release Kinetics.

PURPOSE: This study systematically investigated the potential of four model drugs (verapamil HCl, flurbiprofen, atenolol, and furosemide), each belonging to a different class of Biopharmaceutics Classification Systems (BCS) to be developed into oral modified release dosage forms after loading with halloysite nanotubes (HNTs). METHODS: The drugs were studied for their loading (mass gain %) by varying solvent system, method, pH, and ratios of loading into the nanotubes using D-optimal split-plot design with the help of Design Expert software. Drug-loaded halloysites were characterized by XRD, DTA, FTIR, SEM, and HPLC-UV-based assay procedures. Dissolution studies were also performed in dissolution media with pH 1.2, 4.5, and 6.8. Moreover, the optimized samples were evaluated under stress stability conditions for determining prospects for the development of oral dosage forms. RESULTS: As confirmed with the results of XRD and DTA, the drugs were found to be converted into amorphous form after loading with halloysite (HNTs). The drugs were loaded in the range of ~7-9% for the four drugs, with agitation providing satisfactory and equivalent loading as compared to vacuum plus agitation based reported methods. FTIR results revealed either only weak electrostatic (verapamil HCl and flurbiprofen) or no interaction with the surface structure of the HNTs. The dissolution profiling depicted significantly retarded release of drugs with Fickian diffusion from a polydisperse system as a model that suits well for the development of oral dosage forms. HPLC-UV-based assay indicated that except furosemide (BCS class IV), the other three drugs are quite suitable for development for oral dosage forms. CONCLUSION: The four drugs investigated undergo phase transformation with HNTs. While agitation is an optimum method for loading drugs with various physicochemical attributes into HNTs; solvent system, loading ratios and pH play an important role in the loading efficiency respective to the drug properties. The study supports the capability of developing HNT-based modified release oral dosage forms for drugs with high solubility.

Degrees of order: A comparison of nanocrystal and amorphous solids for poorly soluble drugs.

Poor aqueous solubility is currently a prevalent issue in the development of small molecule pharmaceuticals. Several methods are possible for improving the solubility, dissolution rate and bioavailability of Biopharmaceutics Classification System (BCS) class II and class IV drugs. Two solid state approaches, which rely on reductions in order, and can theoretically be applied to all molecules without any specific chemical prerequisites (compared with e.g. ionizable or co-former groups, or sufficient lipophilicity), are the use of the amorphous form and nanocrystals. Research involving these two approaches is relatively extensive and commercial products are now available based on these technologies. Nevertheless, their formulation remains more challenging than with conventional dosage forms. This article describes these two technologies from both theoretical and practical perspectives by briefly discussing the physicochemical backgrounds behind these approaches, as well as the resulting practical implications, both positive and negative. Case studies demonstrating the benefits and challenges of these two techniques are presented.

Simulation-based comparison of Biopharmaceutics Classification System and drug structure.

Background: The Biopharmaceutics Classification System (BCS), which classifies bioactive molecules based on solubility and permeability, is widely used to guide new drug development and drug formulation, as well as predict pharmacokinetics. Here we performed computer simulations to study correlations between a molecule's structure and its BCS classification. Methods: A total of 411 small molecules were assigned to BCS categories based on published drug data, and their Pybel-FP4 fingerprints were extrapolated. The information gain (IG) of each fingerprint was calculated and its characteristic structure analyzed. IG was calculated using multiple thresholds, and results were verified using support vector machine prediction, while taking into account the dose coefficient (0-0.1, 0.1-1, or >1). Structural functional features common to fingerprints of compounds in each type of BCS class were determined using computer simulations. Results: BCS classes III and IV appear to share several structural and functional characteristics, including secondary aliphaticamine, Michael acceptor, isothiourea, and sulfonamide sulfonic derivatives. Conclusion: We demonstrate that our approach can correlate characteristic fingerprints of small-molecule drugs with BCS classifications, which may help guide the development and optimization of new drugs.

Matrix effects of the hydroethanolic extract and the butanol fraction of calyces from Physalis peruviana L. on the biopharmaceutics classification of rutin.

OBJECTIVES: The Biopharmaceutics Classification System (BCS) categorizes active pharmaceutical ingredients according to their solubility and permeability properties, which are susceptible to matrix or formulation effects. The aim of this research was to evaluate the matrix effects of a hydroethanolic extract of calyces from Physalis peruviana L. (HEE) and its butanol fraction (BF), on the biopharmaceutics classification of their major compound, quercetin-3-O-rutinoside (rutin, RU). METHODS: Rutin was quantified by HPLC-UV, and Caco-2 cell monolayer transport studies were performed to obtain the apparent permeability values (Papp ). Aqueous solubility was determined at pH 6.8 and 7.4. KEY FINDINGS: The Papp values followed this order: BF > HEE > RU (1.77 ± 0.02 > 1.53 ± 0.07 > 0.90 ± 0.03 × 10-5  cm/s). The lowest solubility values followed this order: HEE > RU > BF (2.988 ± 0.07 > 0.205 ± 0.002 > 0.189 ± 0.005 mg/ml). CONCLUSIONS: According to these results, rutin could be classified as BCS classes III (high solubility/low permeability) and IV (low solubility/low permeability), depending on the plant matrix. Further work needs to be done in order to establish how apply the BCS for research and development of new botanical drugs or for bioequivalence purposes.

ICH M9 Guideline in Development on Biopharmaceutics Classification System-Based Biowaivers: An Industrial Perspective from the IQ Consortium.

In October 2016, the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) ICH began efforts to provide recommendations to harmonize guidances for biopharmaceutics classification system (BCS)-based biowaivers. Topics to be addressed included consideration of the dose used to classify solubility, tests, and criteria for establishing highly permeable, dissolution conditions, the influence of excipients, and aspects of product strength. The International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) is a technically focused organization of pharmaceutical and biotechnology companies with a mission of advancing science and technology to augment the capability of member companies to develop transformational solutions that benefit patients, regulators, and the broader R&D community. Its members have substantial expertise in all scientific domains associated with BCS-based waivers and drug product quality, as well as considerable experience in the application of BCS-based biowaivers. The ICH process recognizes that harmonization is achieved through the development of guidelines via a process of scientific consensus with regulatory and industry experts working side-by-side. Thus, to facilitate these efforts and to encourage open and transparent discussion of other perspectives that may exist, IQ offers their perspective on these and related topics.

The Relationship between Bitter Taste Sensor Response and Physicochemical Properties of 47 Pediatric Medicines and Their Biopharmaceutics Classification.

The purpose of this study was to investigate the relationship between response to the bitterness taste sensor and physicochemical parameters of 47 pediatric medicines and to classify these medicines according to the biopharmaceutics classification system (BCS). Forty-seven bitter compounds, most of which were on the WHO model list of essential medicines for children (March 2017), were used in the study. Solutions (0.1 mM) were evaluated by an artificial taste sensor using membranes sensitive to bitterness. On the basis of principal component analysis of taste sensor measurements, chlorpromazine, haloperidol, propranolol, amitriptyline, diphenhydramine were predicted to express the strongest levels of basic bitterness, surpassing that of quinine. Correlation tests between bitter taste sensor outputs and physicochemical properties were then carried out and the compounds classified in terms of their biopharmaceutical properties. High log P values (≥2.82), physiological charge (≥1), low log S values (<-3) and small polar surface area (PSA; <45.59 Å2) were found to correlate significantly with the responses of bitter taste sensors. Forty-one of the 47 compounds could be placed into one of four groups in the BCS, on the basis of dose number (D0), an indicator of solubility which takes into account clinical dosage, and fractional absorption (Fa). For medicines classified in group 4, the factors D0 > 1 and Fa < 0.85 significantly correlated with the responses of the taste sensor for basic bitterness. It was concluded that lipophilicity, physiological charge, solubility, PSA and D0 are the main factors affecting the bitterness of pediatric medicines.

[Research and development thought on biopharmaceutics classification system of Chinese materia medica].

The biopharmaceutics classification system( BCS) is a scientific framework or method for classifying drugs based on drug solubility and permeability,which can be used to provide drug bioavailability-absorption correlation analysis. Based on the characteristics of multi-component and multi-target of traditional Chinese medicine( TCM) as well as the concept,method and technology of BCS,the research group proposed biopharmaceutics classification system of Chinese materia medica( CMMBCS) and carried out research and data accumulation of classical prescriptions. Based on the previous research results,further development ideas under the CMMBCS concept and framework were further proposed in this study. In the course of research,the influence of the intermediate links of the complex interactions of the multi-component environment was omitted,and the component absorption studies on the main clinical effects of prescription ingredients were directly concerned,or the components and data were reversely extracted from the aspects of metabolism,pharmacodynamic pathways and absorption principles. Studies were conducted from two aspects( single component and compound prescription) to comprehensively evaluate the absorption properties of TCM compound. In the research path,the different ways in which Chinese medicine could exert its efficacy were fully considered,and CMMBCS classification and establishment rules were clarified mainly by focusing on the absorption pathway into the blood. Specifically,the network pharmacology and molecular docking technology were used to screen the compound index components of TCM; the absorption rules were studied by the physiologically based pharmacokinetic models and the absorption parameters of CMMBCS were calculated by reverse reasoning. Then the CMMBCS classification of TCM prescription was corrected by studying the efficacy or absorption pathway. In this paper,the theoretical framework and research methodology of CMMBCS were systematically improved based on the establishment of CMMBCS basic theory,the supplementary of drug-oriented research ideas and the application of modern mature Chinese medicine methodology.

[Research on attributes of biopharmaceutics classification system for Chinese materia medica of baicalein in Gegen Qinlian Decoction environment].

For the effects of multi-component environment on the solubility and permeability of single components,and the problems of biopharmaceutical attribute classification of single components in the compound prescriptions environment,baicalein was used as the research object in this study to investigate the biopharmaceutic attributes of single-component and their traditional Chinese medicine( TCM) biopharmaceutic attributes in the multi-component environment of Gegen Qilian Decoction. Shaking flask method,intrinsic dissolution rate test and HPLC were used to determine solubility of baicalein. Markers specified by FDA were utilized as permeable boundary reference materials to verify the applicability of the single-pass intestinal perfusion method( SPIP),and the quantitative research on the permeability of baicalein was also conducted. It is concluded that baicalein could be categorized as BCS-Ⅱ drug based on its low solubility and high intestinal permeability values,and it may be categorized into CMMBCS-I in the multi-component environment of Gegen Qilian Decoction due to its poor solubility but enhanced solubility and permeability in compound environment. This study could provide verification ideas for clinical determination of the best human oral dose of baicalein,and provide the data basis for the study of biopharmaceutics classification system of Chinese materia medica( CMMBCS).

[Study on biopharmaceutics classification system of Chinese materia medica for Gegen Qinlians Tablets based on anti-inflammatory activity].

The research on biopharmaceutics classification system of Chinese materia medica( CMMBCS) should be finally implemented to the holistic research level of traditional Chinese medicine compounds,while the overall biopharmaceutical properties of traditional Chinese medicine compounds are not only the sum of solubility and permeability of each component. In this study,Gegen Qinlian Tablets was used as the research object,and the contents of 12 representative components,i.e. puerarin,daidzin,baicalin,daidzein,wogonoside,baicalein,wogonin,glycyrrhizic acid,coptisine hydrochloride,epiberberine,berberine hydrochloride and palmatine hydrochloride,were simultaneously determined by HPLC to obtain the mass weight of each component. The in vitro lipopolysaccharide( LPS)-induced RAW264. 7 cells inflammation model was established to investigate the anti-inflammatory effects of 12 representative components and obtain the efficacy weight of each component. In order to obtain the number of doses and effective permeability coefficient which can represent the overall biopharmaceutical properties of Gegen Qinlian Tablets,mass weight was combined with efficacy weight to integrate the solubility and permeability data of each component determined by typical shake flask method and in situ single pass intestinal perfusion model respectively. The results indicated that Gegen Qinlian Tablets should be categorized Ⅳ drug of the CMMBCS with low solubility and low permeability.

Reconciling Human-Canine Differences in Oral Bioavailability: Looking beyond the Biopharmaceutics Classification System.

The extrapolation of oral bioavailability (F) information between dogs and humans has had an important role in the drug development process, whether it be to support an assessment of potential human pharmaceutical formulations or to identify the bioavailability challenges that may be encountered in dogs. Accordingly, these interspecies extrapolations could benefit from a tool that helps identify those drug characteristics consistent with species similarities in F. Our initial effort to find such a tool led to an exploration of species differences as it pertained to the biopharmaceutics classification system (BCS). However, using a range of compounds, we concluded that solubility and permeability alone could not explain interspecies inconsistencies in estimates of F. Therefore, we have now extended our evaluation to include canine versus human comparisons of F based upon the biopharmaceutics drug disposition classification system (BDDCS) and the extended clearance classification system (ECCS). Using the same data as that in our initial BCS assessments, we conclude that although neither the BDDCS nor the ECCS can reliably improve our ability to determine when F will be similar in humans and dogs, the ECCS provides a mechanism to help define possible causes for observed human-canine inconsistencies.

The Biopharmaceutics Classification System (BCS) and the Biopharmaceutics Drug Disposition Classification System (BDDCS): Beyond guidelines.

The recent impact of the Biopharmaceutics Classification System (BCS) and the Biopharmaceutics Drug Disposition Classification System (BDDCS) on relevant scientific advancements is discussed. The major advances associated with the BCS concern the extensive work on dissolution of poorly absorbed BCS class II drugs in nutritional liquids (e.g. milk, peanut oil) and biorelevant media for the accurate prediction of the rate and the extent of oral absorption. The use of physiologically based pharmacokinetic (PBPK) modeling as predictive tool for bioavailability is also presented. Since recent dissolution studies demonstrate that the two mechanisms (diffusion- and reaction-limited dissolution) take place simultaneously, the neglected reaction-limited dissolution models are discussed, regarding the biopharmaceutical classification of drugs. Solubility- and dissolution-enhancing formulation strategies based on the supersaturation principle to enhance the extent of drug absorption, along with the applications of the BDDCS to the understanding of disposition phenomena are reviewed. Finally, recent classification systems relevant either to the BCS or the BDDCS are presented. These include: i) a model independent approach based on %metabolism and the fulfilment (or not) of the current regulatory dissolution criteria, ii) the so called ΑΒΓ system, a continuous version of the BCS, and iii) the so-called Extended Clearance Classification System (ECCS). ECCS uses clearance concepts (physicochemical properties and membrane permeability) to classify compounds and differentiates from BDDCS by bypassing the measure of solubility (based on the assumption that since it inter-correlates with lipophilicity, it is not directly relevant to clearance mechanisms or elimination).

Application of a Refined Developability Classification System.

In 2010, the Developability Classification System was proposed as an extension of the Biopharmaceutics Classification System to align the classification system with the need for early evaluation of drug candidates according to their developability as oral formulations. Recent work on the Developability Classification System has resulted in the refined developability classification system (rDCS), consisting of standard investigations to estimate drug candidate solubility and permeability and offering customized investigations that are triggered when there is a potential for supersaturation/precipitation (e.g., salts of acids, weak bases) or to investigate permeation versus dissolution-limited absorption. In the present study, the rDCS concept was successfully applied to 6 marketed compounds (aciclovir, albendazole, danazol, dantrolene, dipyridamole, and piroxicam), for which there is a rich database of information. Furthermore, the rDCS was applied to 20 pipeline compounds from past and current research projects at Bayer AG. The rDCS was able to predict the results in humans correctly in 80% of cases. Overall, the results suggest that the rDCS is a highly useful tool for estimating the in vivo behavior of new drug candidates.

Nano-sized Droplets of Self-Emulsifying System for Enhancing Oral Bioavailability of Chemotherapeutic Agent VP-16 in Rats: A Nano Lipid Carrier for BCS Class IV Drugs.

PURPOSE: The purpose of this study was to investigate the ability of a self-nano-emulsifying drug delivery system (SNEDDS) to enhance the oral bioavailability of a BCS class IV drug, etoposide (VP-16). METHOD: A series of SNEDDS formulations with VP-16 were prepared consisting of medium chain triglycerides, polysorbate 80, diethylene glycol monoethyl ether and propylene glycol monolaurate type-1.  Based on an obtained ternary phase diagram, an optimum formulation was selected and characterized in terms of size, zeta potential, loading, morphology and in vitro drug release. The pharmacokinetic parameters and oral bioavailability of VP-16 suspension and VP-16 in SNEDDS was assessed using 30 Male Sprague-Dawley rats and compared with the commercial product (VePesid®). RESULTS: Pharmacokinetic data showed that the mean values for AUC0-t of VP-16 in SNEDDS was 6.4 fold higher compared to a drug suspension and 2.4-folds higher than VePesid®. Similarly, the mean value for Cmax of VP-16 in SNEDDS (1.13± 0.07 µg/ml µg.h/mL) was higher than VePesid® (0.62± 0.09 µg/mL) and drug suspension (0.13± 0.07 µg/mL). CONCLUSION: The SNEDDS formulation was able to enhance the oral bioavailability of the BCS Class IV chemotherapeutic agent VP-16 by increasing the dissolution and absorption of the drug. A good in vitro in vivo correlation was found between the in vitro dissolution and in vivo absorption data of VP-16 SNEDDS preparation. Therefore, SNEDDS formulations might be a very promising approach for BCS Class IV drugs.

Polymorphic and Quantum Chemistry Characterization of Candesartan Cilexetil: Importance for the Correct Drug Classification According to Biopharmaceutics Classification System.

The recommended method for the biopharmaceutical evaluation of drug solubility is the shake flask; however, there are discrepancies reported about the solubility of certain compounds measured with this method, one of them is candesartan cilexetil. The present work aimed to elucidate the solubility of candesartan cilexetil by associating others assays such as stability determination, polymorphic characterization and in silico calculations of intrinsic solubility, ionized species, and electronic structures using quantum chemistry descriptors (frontier molecular orbitals and Fukui functions). For the complete biopharmaceutical classification, we also reviewed the permeability data available. The polymorphic form used was previously identified as the form I of candesartan cilexetil. The solubility was evaluated in biorelevant media in the pH range of 1.2-6.8 at 37.0°C according to the stability previously assessed. The solubility of candesartan cilexetil is pH dependent and the dose/solubility ratios obtained demonstrated the low solubility of the prodrug. The in silico calculations supported the found results and evidenced the main groups involved in the solvation, benzimidazole, and tetrazol-biphenyl. The human absolute bioavailability reported demonstrates that candesartan cilexetil has low permeability and when associated with the low solubility allows to classify it as class 4 of the Biopharmaceutics Classification System.

Comparative Oral Drug Classification Systems: Acetazolamide, Azithromycin, Clopidogrel, and Efavirenz Case Studies.

Biopharmaceutics classification systems based on the properties of solubility and permeability or the extension of metabolism are very important tools in the early stages of the development and regulatory stages of new products. However, until now, there was no clear understanding between the interplay among these classification systems. Therefore, the main objective of this work was to make a comparison of concepts of BCS and BDDCS to understand what are the key factors that allow for the integration of these biopharmaceutics classification systems. Also, the suitability of an in situ single-pass intestinal perfusion assay in rats (SPIP) development was assessed by us to determine the limit between high and low permeability following what the FDA BCS guidance suggests. An excellent correlation was found between the values of permeability obtained by applying SPIP assays and the extensions of the metabolism of the set of compounds studied in this work, with the exception of three compounds that showed disparity between their permeability coefficients ( Peff), obtained herein by SPIP, and their metabolism (acetazolamide, azithromycin, and efavirenz). Discrepancies allowed us to elucidate the interrelationship between BCS and BDDCS.

Biopharmaceutical optimization in neglected diseases for paediatric patients by applying the provisional paediatric biopharmaceutical classification system.

AIMS: Unavailability and lack of appropriate, effective and safe formulations are common problems in paediatric therapeutics. Key factors such as swallowing abilities, organoleptic preferences and dosage requirements determine the need for optimization of formulations. The provisional Biopharmaceutics Classification System (BCS) can be used in paediatric formulation design as a risk analysis and optimization tool. The objective of this study was to classify six neglected tropical disease drugs following a provisional paediatric BCS (pBCS) classification adapted to three paediatric subpopulations (neonates, infants and children). METHODS: Albendazole, benznidazole, ivermectin, nifurtimox, praziquantel and proguanil were selected from the 5th edition of the Model List of Essential Medicines for Children from the World Health Organization. Paediatric drug solubility classification was based on dose number calculation. Provisional permeability classification was based on log P comparison versus metoprolol log P value, assuming passive diffusion absorption mechanisms and no changes in passive membrane permeability between paediatric patients and adults. pBCS classes were estimated for each drug, according to different doses and volumes adapted for each age stage and were compared to the adult classification. RESULTS: All six drugs were classified into provisional pBCS in the three paediatric subpopulations. Three drugs maintained the same classification as for adults, ivermectin and benznidazole changed solubility class from low to high in neonates and proguanil changed from low to high solubility in all age stages. CONCLUSION: Provisional pBCS classification of these six drugs shows potential changes in the limiting factors in oral absorption in paediatrics, depending on age stage, compared to the adult population. This valuable information will aid the optimization of paediatric dosing and formulations and can identify bioinequivalence risks when comparing different formulations and paediatric populations.

A Refined Developability Classification System.

In 2010, the Developability Classification System (DCS) was proposed. The DCS was designed to close the gap between the biopharmaceutics classification system, which is aimed at guiding regulatory decisions about well-characterized drugs, and the need for early evaluation of drug candidates with respect to their suitability for oral delivery. The DCS applied solubility in fasted state simulated intestinal fluid to estimate intestinal solubility, assessed the compensatory nature of permeability and solubility during oral absorption and provided a way of estimating the critical the particle size at which dissolution becomes rate-limiting to absorption. Building on this framework, a refined developability classification system (rDCS) is now proposed. The rDCS is stratified into standard investigations applied to all candidates, and customized investigations. Standard investigation of solubility and permeability can be performed according to in-house methods, and the results compared with standard data sets of fasted state human intestinal fluid solubility and human effective jejunal permeability, which have been generated specifically for rDCS. Customized investigations are triggered when there is potential for supersaturation/precipitation (weak bases; salts of weak acids) and to assess dissolution versus permeation limited absorption. In addition, the rDCS offers facile visualization of the results, enabling pragmatic comparison of drug candidates and formulation approaches.