BCS Classification Research Articles

In vitro studies for BCS classification of an antiviral agent, Favipiravir

In vitro studies for BCS classification of an antiviral agent, Favipiravir

Heterogeneity of Bal\xf3\u2019s concentric sclerosis: a study of eight cases with different therapeutic concepts

BackgroundBaló’s Concentric Sclerosis (BCS) is a rare heterogeneous demyelinating disease with a variety of phenotypes on Magnetic Resonance Imaging (MRI). Existing literature lacks data especially on the therapeutic approach of the disease which we intended to elucidate by means of suggesting a new possible BCS classification and introducing different therapeutic concepts based on each BCS-subgroup characteristics.MethodsWe present a retrospective study of eight treated patients with BCS-type lesions, emphasizing on MRI characteristics and differences on therapeutic maneuvers.ResultsData analysis showed: at disease onset the BCS-type lesion was tumefactive (size ≥2 cm) in 6 patients, with a mean size of 2.7 cm (± 0.80 SD); a coexistence of MS-like plaques on brain MRI was identified in 7 patients of our cohort. The mean age was 26.3 years (±7.3 SD) at disease onset and the mean follow-up period was 56.8 months (range 9–132 months). According to radiological characteristics and response to therapies, we further categorized them into 3 subgroups: a) Group-1; BCS with or without coexisting nonspecific white matter lesions; poor response to intravenous methylprednisolone (IVMP); treated with high doses of immunosuppressive agents (4 patients), b) Group-2; BCS with typical MS lesions; good response to IVMP; treated with MS-disease modifying therapies (2 patients), c) Group-3; BCS with typical MS lesions; poor response to IVMP; treated with rituximab (2 patients).ConclusionsOur study introduces a new insight regarding the categorization of BCS into three subgroups depending on radiological features at onset and during the course of the disease, in combination with the response to different immunotherapies. Immunosuppressive agents such as cyclophosphamide are usually effective in BCS. However, therapeutic alternatives like anti-CD20 monoclonal antibodies or more classical disease-modifying MS therapies can be considered when BCS has also mixed lesions similar to MS. Future studies with a larger sample size are necessary to further establish these findings, thus leading to better treatment algorithms and improved clinical outcomes.

Predictive and Accelerated Formulation Design Using Synchrotron Methods.

Predictive formulation design and accelerated formulation design can lead to the discovery of useful formulations to support drug clinical studies and successful drug approval. Predictive formulation design can also lead to discovery of a path for commercialization, especially for poorly soluble drugs, when the target product profile is well defined and a "learning before doing" approach is implemented. One of the key components of predictive/accelerated formulation design is to understand and leverage the material properties of drug substance including solubility, BCS classification, polymorphs, salt formation, amorphous form, amorphous complex, and stability. In addition, utilizing synchrotron-based PDF (pair distribution function) analysis can provide important structural information for the formulation. This knowledge allows control of physical and chemical stability of the designed product. Finally, formulation design should link to process development following Quality by Design principles, and solid-state chemistry should play a critical role in many of the steps required to achieve Quality by Design, which can lead to successful product development.

Preparation of sustained release apremilast-loaded PLGA nanoparticles: in vitro characterization and in vivo pharmacokinetic study in rats.

BackgroundApremilast (APM) is a novel, orally administered small molecule drug approved for treatment of psoriasis or psoriatic arthritis. Due to its low solubility and permeability, it is classified as a class IV drug according to BCS classification. Dose titration is recommended during APM treatment due to its tolerability and twice-daily dosing regimen issues.Materials and MethodsIn this study, three different APM-loaded PLGA nanoparticles (F1–F3) were prepared by single emulsion and evaporation method. Based on particle size, PDI, zeta potential (ZP), entrapment efficiency (%EE), drug loading (%DL), and spectral characterization, the nanoparticles (F3) were optimized. The F3 nanoparticles were further evaluated for in vitro release and in vivo pharmacokinetic studies in rats.ResultsThe optimized nanoparticles (F3) had particles size 307.3±8.5 nm with a low PDI value 0.317, ZP of −43.4±2.6 mV, EE of 61.1±1.9% and DL of 1.9±0.1%. The in vitro release profile showed a sustained release pattern of F3 nanoparticles of APM. The pharmacokinetic results showed 2.25 times increase in bio-availability of F3 nanoparticles compared to normal APM suspension. Moreover, significant increase in half-life and mean residence time confirms long-term retention of F3 nanoparticles.ConclusionBioavailability enhancement along-with long-term retention of the APM-loaded PLGA nanoparticles might be helpful for the once-daily regimen treatment.

SOLUBILITY ENHANCEMENT OF POORLY WATER SOLUBLE DRUGS BY VARIOUS TECHNIQUES

Solubility is not the ability to dissolve or thaw a substance; it may happen not only due to dissolution but also because of a chemical reaction. Solubility is the phenomenon of dissolution of solid in liquid phase to provide a homogenous system. Solubility is one of the vital factors for accomplishing desired concentration of drug in systemic circulation for pharmacological response. Low aqueous solubility is the major problem seen with formulation development of new chemical entities as well as for the generic development. With all new discovered chemical entities about 40% drugs are lipophilic and doesn’t shown therapeutic range due to their poor water solubility. Drug with poor water solubility shows slow dissolution rates, incomplete absorption and low bioavailability when taken orally. Drug solubility and bioavailability enhancement are the important in the formulation of pharmaceuticals. The Biopharmaceutics Classification System shows that Class II and IV drugs have low water solubility, poor dissolution, and low bioavailability. This review mentions different approaches used for the enhancement of the solubility of poorly water-soluble drugs that includes particle size reduction, pH adjustment, and solid dispersion. This describes the techniques of solubilizaton for the attainment of effective absorption and improved bioavailability.
 Keywords: Solubility, BCS classification, Bioavailability, Solid-dispersion.

Determination of intestinal permeability using in situ perfusion model in rats: Challenges and advantages to BCS classification applied to digoxin

The purpose of this work was to describe the closed loop in situ perfusion method in rats and to compare the difficulties and advantages with other methods proposed by regulatory agencies for BCS classification and finally to illustrate its application to evaluate the permeability of digoxin at relevant clinical concentrations. Digoxin was evaluated at two concentration levels: 1.0 μg/ml (with and without sodium azide 65.0 μg/ml) and 6.0 μg/ml. These concentrations correspond to the ratio of the highest dose strength (0.25 mg) and the highest single dose administered (1.5 mg) and the 250 ml of water. In situ closed loop perfusion studies in rats were performed in the whole small intestine and also in duodenum, jejunum and ileum segments to evaluate the relevance of P-gp secretion in the overall permeability. A kinetic modelling approach involving passive permeation and efflux transport mechanism allowed the estimation of the passive diffusional component and the Michaelis-menten parameters. The estimated Km value demonstrated that at clinical luminal concentrations the efflux process is not saturated and then it could be inhibited by other drugs, excipients or food components leading to the already reported clinical drug-drug and drug-food interations. The present data confirms from a mechanistic point of view these interactions.

Improving Solubility of the Telmisartan that is Poorly Water Soluble by Wet Granulation and Vitrification Process

Telmisartan (TS) have developed for the treatment of hypertension as the angiotensin II receptor blocker. TS belongs to class II drug in BCS classification and it has good permeability. But, it is poorly water soluble. Biological half-life of TS is 24 hours because it has not good bioavailability (only 42∼58%). The absorption of a drug is often limited by dissolution rate. Drug dissolution is important factor to the therapeutic efficacy of a medicine. Therefore, TS requires alternative methods of drug delivery system to improve solubilization. In this study, we have prepared solid dispersions (SD) of the TS, polyvinylpyrrolidone (PVP) K-30 using rotary evaporation to promote release rate. So, we made sustained release formulation to make that is continually released and reduced the number of administration to patients. We selected the methods which are wet granulation (WG) and vitrification (VT) for sustained release. WG is a common techinique in the pharmaceutical industry that is mixing the powder to make bonds between powder particles using water. VT is techinique that transforms the crystalline particle into amorphous state using cryomilling. We measured the characterization of SD that was performed using various methods to analyze the structure of powder sample. Characterizations of SD were performed to analyze the surface by scanning electron microscopy. The crystallinity and molecular structure are analyzed by Fourier transform infrared spectroscopy, powder X-ray diffractometer. Also, thermal porperties are analyzed by differential scanning calorimeter. In vitro dissolution test assessed by RP-HPLC to analyze dissolution rate of sustained release formulation and solid dispersion. In this results, these indicate that both methods improve solubility and dissolution rate. The drug solubility of processed VT almost greater than the pure drug and WG. And, in Bats, VT 3 has higher dissolution rates than others. So, this results are useful to improve TS in the pharmaceutical industry.

PREPARATION, CHARACTERIZATION, AND OPTIMIZATION OF MICROEMULSION FOR TOPICAL DELIVERY OF ITRACONAZOLE

Microemulsions (ME) have been proved to increase the cutaneous absorption of both lipophilic and hydrophilic medicaments when compared to conventional vehicles (emulsions, pure oils, aqueous solutions). Hence the aim of present investigation is to prepare, characterize and optimize microemulsion of Itraconazole (ITZ). Itraconazole is an anti fungal agent, most widely used in the ringworm infection. It is classified as class III drug as per BCS classification. It indicates lower permeability through skin. Therefore objective of the research is to improve permeability of Itraconazole through skin. Microemulsion was prepared using eucalyptus oil, tween 20 and methanol as oil phase, surfactant and co-surfactant respectively. Pseudo ternary phase diagrams were constructed to find out optimum ratio of oil: Smix (surfactant: Co-Surfactant): water. A 32 full factorial design was applied for the optimization of prepared microemulsion. Microemulsion was evaluated for globule size, zeta potential, in-vitro diffusion study etc. Results of globule size measurements and zeta potential indicated ME7 had high stability then other formulation of microemulsion. For the optimization transdermal flux and %Q6 was selected as dependant variables. Results of optimization study also revealed ME 7 as optimized microemulsion for high permeability to the skin. Further ME7 was compared to marketed Itraconazole preparation (ITASPORE) and evaluated using similarity factor F2. Results of F2 value was not near to 100 indicated there is no similarity in diffusion profiles of ME7 and ITASPORE. Hence, indirectly it suggest there was increased in permeability of drug by preparing microemulsion.

Biowaiver or Bioequivalence: Ambiguity in Sildenafil Citrate BCS Classification.

The aim of the present study is to contribute to the scientific characterization of sildenafil citrate according to the Biopharmaceutics Classification System, following the World Health Organization (WHO) guidelines for biowaivers. The solubility and intestinal permeability data of sildenafil citrate were collected from literature; however, the experimental solubility studies are inconclusive and its "high permeability" suggests an API in the borderline of BCS Class I and Class II. The pH-solubility profile was determined using the saturation shake-flask method over the pH range of 1.2-6.8 at a temperature of 37°C in aqueous media. The intestinal permeability was determined in rat by a closed-loop in situ perfusion method (the Doluisio technique). The solubility of sildenafil citrate is pH-dependent and at pH 6.8 the dose/solubility ratio obtained does not meet the WHO criteria for "high solubility." The high permeability values obtained by in situ intestinal perfusion in rat reinforce the published permeability data for sildenafil citrate. The experimental results obtained and the data available in the literature suggest that sildenafil citrate is clearly a Class II of BCS, according to the current biopharmaceutics classification system and WHO guidance.

DISSOLUTION AND SOLUBILITY ENHANCEMENT STRATEGIES: CURRENT and NOVEL PROSPECTIVES

The solubility is one of the important parameters to achieve the desired concentration of the drug in the systemic circulation in pharmacological response to be shown. The oral route is the most desirable and preferred method of administering therapeutic agents for their systemic effects, but the poor solubility of the drug is a major challenge for formulation scientist. Close to 40% of orally administered drugs suffer from formulation difficulties related to their water insolubility. Dissolution rate, absorption, distribution, and excretion of a moiety depend upon its solubility characteristics. Although several advantages associated with the oral route, the poorly soluble drugs suffer from slow dissolution and poor bioavailability. Based on solubility, drugs are classified into four classes of the BCS classification. Solubility challenges are faced in ClassII and Class IV of the BCS system this is important because most of the generic and NCE drugs come under class II drugs. The solubility behavior of drugs remains one of the most challenging aspects of formulation development. There are several methods available for solubility and dissolution enhancement of poorly water-soluble drugs. The aim of this clause is to distinguish the techniques of solubilization for the acquisition of effective absorption and improved bioavailability.

Enhancement of solubility of poorly soluble drugs by solid dispersion: An Overview

Most of the newly invented chemical drug moieties are poorly water soluble. According to BCS classification, class II and IV drugs are considered as poorly water soluble. So enhancement of oral absorption and bioavailability of solid dosage forms remains a challenge to formulation scientists due to their solubility criteria. Therefore many techniques are being explored to enhance the solubility of poor soluble drugs. Solid dispersion is one of the most important method for enhance the solubility (dissolution rate) and hence oral bioavailability of poorly soluble drugs. In solid dispersion the particle size of drug is reduced or a crystalline pure drug is converted into amorphous form and hence the solubility is increased. Polymer incorporating in solid dispersion technology is usually hydrophilic in nature and also showing compatibility with the drug to enhance the drug solubility. This review mainly discus about solid dispersion, preparation methods, and finally characterization.

Solubility Enhancement Techniques for Poorly Water-Soluble Drugs

Solubility is the phenomenon of dissolution of solid in liquid phase to give a homogenous system. Solubility is one of the important parameter to achieve desired concentration of drug in systemic circulation for optimum pharmacological response. Poorly water-soluble drugs often require high doses in order to reach therapeutic plasma concentrations after oral administration. Poor aqueous solubility is a major problem encountered with formulation development of new chemical entities. There are over 40% of new chemical entities that exhibit poor solubility and low bioavailability. As per BCS classification system, these drugs comes under BCS class II that show poor solubility and high permeability. The bioavailability of these drugs can be dramatically improved by increasing the solubility of these drugs. This review article highlights a number of techniques for enhanc

Comparison of Visceral Fat Accumulation and Metabolome Markers among Cats of Varying BCS and Novel Classification of Feline Obesity and Metabolic Syndrome.

As in humans, obesity and its associated diseases represent the most significant threat to the health of veterinary populations. Previous human studies have provided insights into the risk factors of obesity, complex pathogenesis of obesity-associated diseases, and their life-threatening consequences. In humans, the “metabolic syndrome” represents a cluster of metabolic risk factors associated with the development of cardiovascular disease. Risk factors for metabolic syndrome, such as diabetes, obesity, high blood pressure, and its complications increase health-care utilization and medical expenses. Early diagnosis and intervention through preemptive approach is in need, and the new International Diabetes Federation definition of MS serves as the universally accepted diagnostic tool that is accessible in clinical settings. In veterinary populations, especially in cats, similar pathophysiological path and disease progression to the development of MS, such as adipokine dysregulations, chronic inflammation, lipotoxicity, are expected. The aim of this manuscript is twofold. First of all, it presents our preliminary feline obesity study that serves as the basis for discussion of obesity and its metabolic impact on feline population. In this study, we observed the effects of weight gain on energy metabolism using metabolome markers, such as adiponectin (ADN) and proinflammatory cytokines, in correlation with other common biochemical parameters in 14 clinically healthy cats of varying weight status. Further, we evaluated the visceral fat accumulation in three subjects of varying Body Condition Scores via computed tomography imaging and laparoscopic examination, and assessed the adipocyte type and size histologically. Mutually antagonizing changes in ADN and visceral adipose tissue (VAT) reflected the pathophysiological derangements leading to MS earlier than the common biochemical predictors such as glucose, liver values, and lipid markers. Second, it proposes the novel diagnostic and classification method of feline obesity and MS, based on the established diagnostic criteria of human MS and the presented study results. The results supported our novel “classification of feline obesity” and “Feline MS diagnostic criteria,” suggesting the need to complement ADN measurement with VAT volume to better understand the pathogenesis of metabolic disturbances in the feline population.

Intranasal brain-targeted clonazepam polymeric micelles for immediate control of status epilepticus: in vitro optimization, ex vivo determination of cytotoxicity, in vivo biodistribution and pharmacodynamics studies

Clonazepam (CZ) is an anti-epileptic drug used mainly in status epilepticus (SE). The drug belongs to Class II according to BCS classification with very limited solubility and high permeability and it suffers from extensive first-pass metabolism. The aim of the present study was to develop CZ-loaded polymeric micelles (PM) for direct brain delivery allowing immediate control of SE. PM were prepared via thin film hydration (TFH) technique adopting a central composite face-centered design (CCFD). The seventeen developed formulae were evaluated in terms of entrapment efficiency (EE), particle size (PS), polydispersity index (PDI), zeta potential (ZP), and in vitro release. For evaluating the in vivo behavior of the optimized formula, both biodistrbution using 99mTc-radiolabeled CZ and pharmacodynamics studies were done in addition to ex vivo cytotoxicty. At a drug:Pluronic® P123:Pluronic® L121 ratio of 1:20:20 (PM7), a high EE, ZP, Q8h, and a low PDI was achieved. The biodistribution studies revealed that the optimized formula had significantly higher drug targeting efficiency (DTE = 242.3%), drug targeting index (DTI = 144.25), and nose-to-brain direct transport percentage (DTP = 99.30%) and a significant prolongation of protection from seizures in comparison to the intranasally administered solution with minor histopathological changes. The declared results reveal the ability of the developed PM to be a strong potential candidate for the emergency treatment of SE.

Review on Solubility Enhancement Techniques

Absorption process is develop in biological system to getting required organic and inorganic chemicals in to systemic circulation and maintain bioavailability. The bioavailability issue can be due to insufficient solubility or permeability. Most compounds face the solubility problems. Hence, with the advancement of chemical science, the need of development of pharmaceutical technologies is also increasing and it depend upon drug to drug. The drug exhibit very poor aqueous solubility the rate at which drug dissolve in gastro intestinal tract and exhibit rate limiting step. Oral route is the most desirable and preferred method of administering therapeutic agents for their systemic effect On the basis of solubility, drugs are classified into four classes of the BCS classification. Solubility challenges are faced in the Class II and Class IV of the BCS system. To improve solubility and bioavailability of poorly soluble drug we use various methods or techniques. Various techniques are used for the enhancement of the solubility of poorly soluble drugs which include physical and chemical modifications of drug and other methods like particle size reduction, crystal engineering, salt formation, solid dispersion, use of surfactant, complexation, and so forth. Selection of solubility improving method depends on drug property, site of absorption, and required dosage form characteristics.

Development and characterization of Telmisartan self-microemulsifying drug delivery system for bioavailability enhancement

Telmisartan is a potent, long-lasting, nonpeptide antagonist of the angiotensin II type-1 (AT1) receptor that is indicated for the treatment of essential hypertension. It belongs to a class II drug in BCS classification i.e. low solubility and high permeability. One of the major problems with this drug is its low solubility in biological fluids which results into poor bioavailability after oral administration. The objective of present work was to develop a self microemulsifying drug delivery system (SMEDDS) to enhance the oral bioavailability of poorly water soluble Telmisartan. SMEDDS is a mixture of oil, surfactant, and cosurfactant, which are emulsified in aqueous medium under gentle digestive motility in the gastrointestinal tract. Psuedoternary phase diagrams were constructed to identify the efficient self-emulsifying region. A SMEDDS were further evaluated for its percentage transmittance, emulsification time, drug content, phase separation, globule size, zeta potential, pH, refractive index, X-ray diffraction, Differential scanning calorimetry and in vitro dissolution studies. Optimized formulation was also compared with marketed product (Telma 20) in male spraguedawley rats. The pharmacokinetic study exhibited 1.54 fold increase in the oral bioavailability of Telmisartan SMEDDS compared with the Marketed product.

In-situ intestinal rat perfusions for human Fabs prediction and BCS permeability class determination: Investigation of the single-pass vs. the Doluisio experimental approaches

Intestinal drug permeability has been recognized as a critical determinant of the fraction dose absorbed, with direct influence on bioavailability, bioequivalence and biowaiver. The purpose of this research was to compare intestinal permeability values obtained by two different intestinal rat perfusion methods: the single-pass intestinal perfusion (SPIP) model and the Doluisio (closed-loop) rat perfusion method. A list of 15 model drugs with different permeability characteristics (low, moderate, and high, as well as passively and actively absorbed) was constructed. We assessed the rat intestinal permeability of these 15 model drugs in both SPIP and the Doluisio methods, and evaluated the correlation between them. We then evaluated the ability of each of these methods to predict the fraction dose absorbed (Fabs) in humans, and to assign the correct BCS permeability class membership. Excellent correlation was obtained between the two experimental methods (r2=0.93). An excellent correlation was also shown between literature Fabs values and the predictions made by both rat perfusion techniques. Similar BCS permeability class membership was designated by literature data and by both SPIP and Doluisio methods for all compounds. In conclusion, the SPIP model and the Doluisio (closed-loop) rat perfusion method are both equally useful for obtaining intestinal permeability values that can be used for Fabs prediction and BCS classification.

Modified Nonsink Equation for Permeability Estimation in Cell Monolayers: Comparison with Standard Methods

Cell culture permeability experiments are valuable tools in drug development and candidate selection, but the monolayer preparation protocols and the calculations procedures can affect the permeability estimation. Hence, standardization and method suitability demonstration are necessary steps for using permeability data for regulatory and in vivo prediction purposes. Much attention is usually paid to experimental procedure validation and less to the mathematical analysis of the results although the standard equations used imply several assumptions that many times do not hold. The aim of this study was to use a simulation strategy to explore the performance of a new proposed modified nonsink equation (MNS) for unidirectional apparent permeability estimation in different types of profiles (of cumulative drug amounts versus time) including those in which the initial permeation rate is altered, considering several levels of experimental variability. The second objective was to compare the MNS method with the classical sink and nonsink approaches and finally to explore its usefulness for BCS classification. Real data from permeability experiments representing atypical profiles have been used for fitting with the three approaches, MNS, sink, and nonsink equations, in order to validate the performance of the new proposed model. The results demonstrated that the MNS method is a precise and accurate equation for calculating the apparent unidirectional permeability in any type of profile and different scenarios of variability, in any sink and nonsink conditions, while the standard nonsink equation fails in obtaining good permeability estimations in those situations in which the initial permeation rate is altered. Linear regression models (S and SC) are not valid under nonsink conditions, as expected, as the underlying assumptions (sink conditions) do not hold, but also in situations in which sink conditions are fulfilled but the system variability is high.

Equilibrium solubility versus intrinsic dissolution: characterization of lamivudine, stavudine and zidovudine for BCS classification

Solubility and dissolution rate of drugs are of major importance in pre-formulation studies of pharmaceutical dosage forms. The solubility improvement allows the drugs to be potential biowaiver candidates and may be a good way to develop more dose-efficient formulations. Solubility behaviour of lamivudine, stavudine and zidovudine in individual solvents (under pH range of 1.2 to 7.5) was studied by equilibrium solubility and intrinsic dissolution methods. In solubility study by equilibrium method (shake-flask technique), known amounts of drug were added in each media until to reach saturation and the mixture was subjected to agitation of 150 rpm for 72 hours at 37 ºC. In intrinsic dissolution test, known amount of each drug was compressed in the matrix of Wood's apparatus and subjected to dissolution in each media with agitation of 50 rpm at 37 ºC. In solubility by equilibrium method, lamivudine and zidovudine can be considered as highly soluble drugs. Although stavudine present high solubility in pH 4.5, 6.8, 7.5 and water, the solubility determination in pH 1.2 was not possible due stability problems. Regarding to intrinsic dissolution, lamivudine and stavudine present high speed of dissolution. Considering a boundary value presented by Yu and colleagues (2004), all drugs studied present high solubility characteristics in intrinsic dissolution method. Based on the obtained results, intrinsic dissolution seems to be superior for solubility studies as an alternative method for biopharmaceutical classification purposes.

The complexity of intestinal permeability: Assigning the correct BCS classification through careful data interpretation

While the solubility parameter is fairly straightforward when assigning BCS classification, the intestinal permeability (Peff) is more complex than generally recognized. In this paper we emphasize this complexity through the analysis of codeine, a commonly used antitussive/analgesic drug. Codeine was previously classified as a low-permeability compound, based on its lower LogP compared to metoprolol, a marker for the low–high permeability class boundary. In contrast, high fraction of dose absorbed (Fabs) was reported for codeine, which challenges the generally recognized Peff–Fabs correlation. The purpose of this study was to clarify this ambiguity through elucidation of codeine’s BCS solubility/permeability class membership. Codeine’s BCS solubility class was determined, and its intestinal permeability throughout the small intestine was investigated, both in vitro and in vivo in rats. Codeine was found to be unequivocally a high-solubility compound. All in vitro studies indicated that codeine’s permeability is higher than metoprolol’s. In vivo studies in rats showed similar permeability for both drugs throughout the entire small-intestine. In conclusion, codeine was found to be a BCS Class I compound. No Peff–Fabs discrepancy is involved in its absorption; rather, it reflects the risk of assigning BCS classification based on merely limited physicochemical characteristics. A thorough investigation using multiple experimental methods is prudent before assigning a BCS classification, to avoid misjudgment in various settings, e.g., drug discovery, formulation design, drug development and regulation.