Physiologically Relevant In Vitro-In Vivo Correlation (IVIVC) Approach for Sildenafil with Site-Dependent Dissolution

In vitro-in vivo correlation (IVIVC) development for long-acting injectable drug products based on poly(lactide-co-glycolide)

In vitro-in vivo correlation (IVIVC), linking in vitro drug release to in vivo drug release or in vivo drug absorption, has been explored chiefly for oral extended-release dosage forms. Currently, there are no official guidelines on IVIVC development for non-oral drug delivery systems. Recently, many long-acting injectable (LAI) formulations based on poly(lactide-co-glycolide) (PLGA) have been developed to deliver various drugs, ranging from small molecules to peptides and proteins, for up to 6 months. The circumstances involved in the LAI formulations are drastically different from those in oral formulations, which generally deliver drugs for a maximum of 24 h. This article examines 37 IVIVC studies of PLGA microparticle formulations available in the literature. Understanding and establishing an IVIVC of LAI formulations requires more than merely plotting the percentage in vitro drug release against the percentage in vivo absorption. In vivo drug absorption (or release) should be measured to provide a complete pharmacokinetic profile when feasible. Accelerated in vitro release methods need to be respective of the real-time measurements by sharing the same release mechanism. Obtaining meaningful IVIVCs with predictive capability will be highly useful for future regulatory actions and for developing generic and new formulations.

A perfectly imperfect engine: Utilizing the digital twin paradigm in pulmonary hypertension

Pulmonary hypertension (PH) is a severe medical condition with a number of treatment options, the majority of which are introduced without consideration of the underlying mechanisms driving it within an individual and thus a lack of tailored approach to treatment. The one exception is a patient presenting with apparent pulmonary arterial hypertension and shown to have vaso-responsive disease, whose clinical course and prognosis is significantly improved by high dose calcium channel blockers. PH is however characterized by a relative abundance of available data from patient cohorts, ranging from molecular data characterizing gene and protein expression in different tissues to physiological data at the organ level and clinical information. Integrating available data with mechanistic information at the different scales into computational models suggests an approach to a more personalized treatment of the disease using model-based optimization of interventions for individual patients. That is, constructing digital twins of the disease, customized to a patient, promises to be a key technology for personalized medicine, with the aim of optimizing use of existing treatments and developing novel interventions, such as new drugs. This article presents a perspective on this approach in the context of a review of existing computational models for different aspects of the disease, and it lays out a roadmap for a path to realizing it.

In vitro dissolution equivalence of Jordanian sildenafil generics via validated, stability-indicating HPLC method

This study was conducted to compare dissolution profiles of four Jordanian registered sildenafil (SDF) products to the originator. Dissolution samples were analyzed utilizing a validated and stability-indicating HPLC method in human plasma. Validation was performed for specificity, linearity, limit of detection, lower limit of quantification, precision, trueness and stability. SDF was extracted from plasma samples using liquid-liquid extraction. The analysis was performed utilizing isocratic elution on C18 column with 1.0 ml/min flow rate. The regression value was ∼0.999 over 3 days with drug recovery between 86.6 to 89.8%with 10 ng/ml lower limit of quantitation. This method displayed a good selectivity of SDF with improved stability under various conditions. The method was used for SDF quantification in dissolution medium. Similarity factors for local products varied according to the used mediums, but all SDF local products passed the dissolution in vitro test since all of them showed a released of >85% after 60 min at the dissolution mediums.

3D human foreskin model for testing topical formulations of sildenafil citrate

Sildenafil citrate is an approved drug used for the treatment of erectile dysfunction and premature ejaculation. Despite a widespread application, sildenafil citrate shows numerous adverse cardiovascular effects in high-risk patients. Local transdermal drug delivery of this drug is therefore being explored as an interesting and noninvasive alternative administration method that avoids adverse effects arised from peak plasma drug concentrations. Although human and animal skin represents the most reliable models to perform penetration studies, they involve a series of ethical issues and restrictions. For these reasons new in vitro approaches based on artificially reconstructed human skin or "human skin equivalents" are being developed as possible alternatives for transdermal testing. There is little information, however, on the efficiency of such new in vitro methods on cutaneous penetration of active ingredients. The objective of the current study was to investigate the sildenafil citrate loaded in three commercial transdermal vehicles using 3D full-thickness skin equivalent and compare the results with the permeability experiments using porcine skin. Our results demonstrated that, while the formulation plays an imperative role in an appropriate dermal uptake of sildenafil citrate, the D coefficient results obtained by using the 3D skin equivalent are comparable to those obtained by using the porcine skin when a simple drug suspension is applied (1.17 × 10-10 ± 0.92 × 10-10 cm2/s vs 3.5 × 102 ± 3.3 × 102 cm2/s), suggesting that in such case, this 3D skin model can be a valid alternative for ex-vivo skin absorption experiments.

Oral Bioavailability and Pharmacokinetics of Sildenafil Orally Disintegrating Tablets under Various Gastric pH Levels Following Administration of Omeprazole in Rats

Sildenafil citrate, an oral drug used to treat erectile dysfunction, has low water solubility and oral bioavailability. The solubility is greatly influenced by the pH, changing from 37.25 mg/mL to 0.22 mg/mL with a change in pH from 1.2 to 8.0. This indicates that the absorption may decrease in patients who use drugs, such as proton pump inhibitors (PPIs), for gastroesophageal reflux disease. To improve the absorption of sildenafil citrate at various gastric pH levels, a sildenafil citrate orally disintegrating tablet (ODT), which has a rapid disintegration feature, was produced by a 3D printing technique. Our study investigated the pharmacokinetic parameters of the sildenafil citrate ODT in rats after oral administration and compared the absorption of the sildenafil citrate ODT and sildenafil citrate commercial tablet (RLD), with and without PPI treatment. The LC/MS/MS analysis of the plasma sildenafil concentration revealed that the area under curve from time 0 to infinity (AUC0-∞) of sildenafil in the sildenafil citrate ODT group was significantly higher than in the sildenafil citrate RLD group whether it was in combination with the PPI or not (274.8% and 144%, respectively; p < 0.05). The relative systemic bioavailability of sildenafil citrate RLD significantly decreased with the PPI, but that of sildenafil citrate ODT was not affected by the PPI. These results indicate that the relative systemic bioavailability of sildenafil citrate ODT was increased when it was prepared using the 3D printing technique and the absorption of this formulation was not affected by the PPI.

Progressive tools and critical strategies for development of best fit PBPK model aiming better in vitro-in vivo correlation

Nowadays, conducting discriminative dissolution experiments employing physiologically based pharmacokinetic modeling (PBPK) or physiologically based biopharmaceutical modeling (PBBM) is gaining significant importance in quantitatively predicting oral absorption of drugs. Mechanistic understanding of each process involved in drug absorption and its impact on the performance greatly facilitates designing a formulation with high confidence. Unfortunately, the biggest challenge scientists are facing in current days is the lack of standardized protocol for integrating dissolution experiment data during PBPK modeling. However, in vitro-in vivo drug release interrelation can be improved with the consideration and development of appropriate biorelevant dissolution media that closely mimic physiological conditions. Multiple reported dissolution models have described nature and functionality of different regions of the gastrointestinal tract (GI) to more accurately design discriminative dissolution media. Dissolution experiment data can be integrated either mechanistically or without a mechanism depending primarily on the formulation type, biopharmaceutics classification system (BCS) class and particle size of the drug substance. All such parameters are required to be considered for selecting the appropriate functions during PBPK modeling to produce a best fit model. The primary focus of this review is to critically discuss various progressive dissolution models and tools, existing challenges and approaches for establishing best fit PBPK model aiming better in vitro-in vivo correlation (IVIVC). Strategies for proper selection of dissolution models as an input function in PBPK/PBBM modeling have also been critically discussed. Logical and scientific pathway for selection of different type of functions and integration events in the commercially available in silico software has been described through case studies.

Model-Informed drug development of gastroretentive release systems for sildenafil citrate

Gastroretentive drug delivery systems (GRDDS) are modified-release dosage forms designed to prolong their residence time in the upper gastrointestinal tract, where some drugs are preferentially absorbed, and increase the drug bioavailability. This work aimed the development of a novel GRDDS containing 60 mg of sildenafil citrate, and the evaluation of the feasibility of the proposed formulation for use in the treatment of pulmonary arterial hypertension (PAH), for once a day administration, by using in silico pharmacokinetic (PK) modeling and simulations using GastroPlus^TM. The Model-Informed Drug Development (MIDD) approach was used in formulation design and pharmacokinetic exposure prospecting. A 2² factorial design with a central point was used for optimization of the formulation, which was produced by direct compression and characterized by some tests, including buoyancy test, assay, impurities, and in vitro dissolution. A compartmental PK model was built using the GatroPlus^TM software for virtual bioequivalence of the proposed formulations in comparison with the defined target release profile provided by an immediate release (IR) tablet formulation containing 20 mg of sildenafil administered three times a day (TID). The results of the factorial design showed a direct correlation between the dissolution rate and the amount of hydroxypropyl methyl cellulose (HPMC) in the formulations. By comparing the PK parameters predicted by the virtual bioequivalence, the formulations F1, F2, F3 and F5 failed on bioequivalence. The F4 showed bioequivalence to the reference and was considered the viable formulation to substitute the IR. Thus, GRDDS could be a promising alternative for controlling the release of drugs with a pH-dependent solubility and narrow absorption window, specifically in the gastric environment, and an interesting way to reduce dose frequency and increase the drug bioavailability. The MIDD approach increases the level of information about the pharmaceutical product and guide the drug development for more assertive ways.

Efficient Evaluation of In Vivo Performance in Human for Generic Formulation by Novel Dissolution-Absorption Prediction (DAP) Workflow

PURPOSE

The pharmaceutical bioequivalence of generic medicines must be confirmed with corresponding original drugs. Although the in vitro dissolution tests are required, results of the mandatory in vitro study do not necessarily reflect the in vivo performance after oral administration. Then, we have tried to develop the novel "Dissolution-Absorption Prediction (DAP) workflow" to evaluate the in vivo performance of generic medicines.

METHODS

The DAP workflow consists of an "In vitro two-cell connected dissolution (TCCD) system" mimicking the changes in the luminal pH associated with gastrointestinal transit of medicines, "Evaluation of pharmacokinetics of active pharmaceutical ingredient (API)" and "Prediction of plasma concentration-time profile". TCCD system-evaluated dissolution kinetics of APIs from generic formulations and pharmacokinetic parameters based on human data regarding the original drugs were used to calculate the plasma concentration-time profiles of APIs after the oral administration of generic medicines.

RESULTS

The mandatory in vitro dissolution tests indicated that the dissolution properties of valsartan (BCS class II) and fexofenadine (BCS class III/IV) in generic formulations did not coincide with those in the corresponding original formulations. The TCCD system provided the very similar dissolution kinetics for the generic and original formulations for the two APIs. Plasma concentration-time profiles evaluated utilizing the dissolution profiles obtained by the TCCD system were in good agreement with the observed profiles for both the generic and original formulations for each API.

CONCLUSIONS

The DAP workflow would be valuable for estimating the in vivo performance of generic formulation and deducing their bioequivalence with the original formulation.

Establishment of Level a In Vitro-In Vivo Correlation (IVIVC) via Extended DoE-IVIVC Model: A Donepezil Case Study

This study aimed to establish an extended design of experiment (DoE)-in vitro in vivo correlation (IVIVC) model that defines the relationship between formulation composition, in vitro dissolution, and in vivo pharmacokinetics. Fourteen sustained-release (SR) tablets of a model drug, donepezil, were designed by applying a mixture design of DoE and prepared by the wet granulation method. The in vitro dissolution patterns of donepezil SR tablets were described by Michaelis-Menten kinetics. The mathematical relationship describing the effects of SR tablet compositions on the in vitro dissolution parameter, i.e., the in vitro maximum rate of release (V_max), was derived. The predictability of the derived DoE model was validated by an additional five SR tablets with a mean prediction error (PE%) of less than 3.50% for in vitro V_max. The pharmacokinetics of three types of donepezil SR and the immediate-release (IR) tablets was assessed in Beagle dogs following oral administration (n = 3, each). Based on the plasma concentration-time profile, a population pharmacokinetic model was developed, and the in vivo dissolution of SR tablets, represented by in vivo V_max, was estimated. By correlating the in vitro and in vivo V_max, level A IVIVC was established. Finally, the extended DoE-IVIVC model was developed by integrating the DoE equation and IVIVC into the population pharmacokinetic model. The extended DoE-IVIVC model allowed one to predict the maximum plasma concentration (C_max) and the area under the plasma concentration-time curve (AUC) of donepezil SR tablets with PE% less than 10.30% and 5.19%, respectively, by their formulation composition as an input. The present extended DoE-IVIVC model may provide a valuable tool to predict the effect of formulation changes on in vivo pharmacokinetic behavior, leading to the more efficient development of SR formulations. The application of the present modeling approaches to develop other forms of drug formulation may be of interest for future studies.

In Vitro-In Vivo Correlation of Tianeptine Sodium Sustained-Release Dual-Layer Tablets

Tianeptine tablets are currently marketed to be designed for immediate-release tablets. The tianeptine has a short half-life, making it difficult to design for sustained-release tablets and achieve bioequivalence with the tianeptine immediate-release tablet (Stablon^®). We established the in vitro-in vivo correlation (IVIVC) of three formulations of tianeptine sustained-release tablets according to their granule size. To evaluate sustained drug release, in vitro tests were performed in pH 1.2 media for 24 h. In vivo pharmacokinetic analysis was performed following oral administration of reference drug and test drug to beagle dogs. The dissolution profile revealed delayed release as the size of the granules increased. The dissolution results were confirmed in pharmacokinetic analysis, showing that the half-life was delayed as granule size increased. The final formulation and reference drug showed an equivalent area under the curve (AUC). Through this, IVIVC was established according to the size of the tianeptine sodium granules, which is the purpose of this study, and was used to predict in vivo pharmacokinetics from the formulation composition. This approach may be useful for determining optimal formulation compositions to achieve the desired pharmacokinetics when developing new formulations.

Opportunities and challenges of physiologically based pharmacokinetic modeling in drug delivery

Physiologically based pharmacokinetic (PBPK) modeling is an important in silico tool to bridge drug properties and in vivo PK behaviors during drug development. Over the recent decade, the PBPK method has been largely applied to drug delivery systems (DDS), including oral, inhaled, transdermal, ophthalmic, and complex injectable products. The related therapeutic agents have included small-molecule drugs, therapeutic proteins, nucleic acids, and even cells. Simulation results have provided important insights into PK behaviors of new dosage forms, which strongly support drug regulation. In this review, we comprehensively summarize recent progress in PBPK applications in drug delivery, which shows large opportunities for facilitating drug development. In addition, we discuss the challenges of applying this methodology from a practical viewpoint.

Pharmacokinetics of panduratin A following oral administration of a Boesenbergia pandurata extract to rats

Boesenbergia pandurata and its major active ingredient, panduratin A (PAN), exhibit antibacterial, anti-oxidant, anti-inflammatory, and anti-obesity effects. We explored the time course of the plasma and tissue (in the major organs, gums and skin) concentrations of PAN after oral administration of a B. pandurata extract to rats. Model-dependent analysis was used to quantify the skin distribution of PAN after systemic exposure. The PAN level peaked at 1.12 ± 0.22 μg/mL after 3 h, and then biexponentially decayed with a terminal half-life of 9 h. The mean clearance (Cl/F) was 2.33 ± 0.68 L/h/kg. The PAN levels in organs were in the following order (highest first): skin, lung, heart, gum, liver, spleen, kidney, and brain. For the first time, the time course of PAN levels in plasma and organs was investigated after oral administration of a BPE. This study helps to explain the pharmacological activities of PAN in the skin and gums. The pharmacokinetic model provided data in the plasma and skin concentrations of PAN, which are of fundamental importance to evaluate its efficacy.

Finding Use for Sorghum Bicolor Leaf Sheath in Coating Technology

This study aimed to investigate the potential use of aqueous extract of Sorghum bicolor leaf sheath (SBLS) as a coating agent for paracetamol tablets. The mechanical properties of the coated tablets were assessed using crushing strength and friability test, while the release properties of the tablet were evaluated using disintegration and dissolution tests. The physicochemical properties of the coated tablets did not show any striking differences when compared with the uncoated tablet as par compendium specifications, which formed the basis for performing further in vitro dissolution study. Our data showed that SBLS enhanced the hardness and friability of the tablets in a dose-dependent manner. Tablets coated with 3, 5, and 7.5% of SBLS disintegrated in 8.13, 6.25, and 4.13 minutes, respectively, while the uncoated tablet disintegrated in 0.7 minutes. Furthermore, 3, 5, and 7.5% of SBLS-coated tablets exhibited slower release of their active ingredient (releasing 21, 16, and 17%, respectively) than that of the uncoated tablet (releasing 40%) in 5 minutes. Besides, comparison between the dissolution profiles was successfully achieved using difference factor (f1) and similarity factor (f2). The apparent dissimilarity between our coated tablets and the uncoated one led to further study of convolution in vitro–in vivo correlation, with the aim to obtain data that converted into mathematical prediction of in vivo data. For all batches, the percent predictable errors of C max and T max were within the acceptable limit of no more than 10%. In summary, SBLS aqueous extract is a potential and protective coat agent for paracetamol tablets. The in vitro established dissolution of the coated tablets provided scientific information for the prediction of the in vivo plasma drug profile.

Changes in the Pharmacokinetics and Pharmacodynamics of Sildenafil in Cigarette and Cannabis Smokers

Sildenafil citrate, a widely-used oral therapy for erectile dysfunction, is a cytochrome P3A4 (CYP3A4) enzyme substrate. Studies have reported that this substrate has an inhibitory effect on CYP3A4 enzymes in long-term cigarette and cannabis smokers, which predominantly mediate the hepatic elimination of sildenafil. Cigarette and/or cannabis smoking could therefore alter the exposure of sildenafil. The aim of this study was to examine the effect of smoking cigarettes and/or cannabis on the pharmacokinetics, pharmacodynamics, safety and tolerability of sildenafil. Thirty-six healthy human subjects were equally divided into three groups: non-smokers, cigarette smokers and cannabis smokers. Each group was administered a single dose of sildenafil (50 mg tablets). The primary outcome measures included the maximum concentration of sildenafil in plasma (C_max), the elimination half-life (t1/2) and the area under the plasma concentration time curve from zero to time (AUC_0-t). The pharmacodynamics were assessed by the International Index of Erectile Function (IIEF-5). The exposure of sildenafil (AUC_0-t) showed a statistically significant increase in cigarette smokers (1156 ± 542 ng·h/mL) of 61% (p < 0.05) while in cannabis smokers (967 ± 262 ng·h/mL), a non-significant increase in AUC_0-t of 35% (p > 0.05) was observed relative to non-smokers (717 ± 311 ng·h/mL). Moreover, the C_max of sildenafil increased by 63% (p < 0.05) and 22% (p > 0.05) in cigarette smokers and cannabis smokers, respectively. Cigarette smoking increases the exposure of sildenafil to a statistically significant level with no effect on its pharmacodynamics, safety and tolerability.

A comparison study of lipid and polymeric nanoparticles in the nasal delivery of meloxicam: Formulation, characterization, and in vitro evaluation

With the increasingly widespread of central nervous system (CNS) disorders and the lack of sufficiently effective medication, meloxicam (MEL) has been reported as a possible medication for Alzheimer's disease (AD) management. Unfortunately, following the conventional application routes, the low brain bioavailability of MEL forms a significant limitation. The intranasal (IN) administration route is considered revolutionary for CNS medications delivery. The objective of the present study was to develop two types of nanocarriers, poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) and solid lipid nanoparticles (SLNs), for the IN delivery of MEL adapting the Quality by Design approach (QbD). Turning then to further enhance the optimized nanoformulation behavior by chitosan-coating. SLNs showed higher encapsulation efficacy (EE) and drug loading (DL) than PLGA NPs 87.26% (EE) and 2.67% (DL); 72.23% (EE) and 2.55% (DL), respectively. MEL encapsulated into the nanoformulations improved in vitro release, mucoadhesion, and permeation behavior compared to the native drug with greater superiority of chitosan-coated SLNs (C-SLNs). In vitro-in vivo correlation (IVIVC) results estimated a significant in vivo brain distribution of the nanoformulations compared to native MEL with estimated greater potential in the C-SLNs. Hence, MEL encapsulation into C-SLNs towards IN route can be promising in enhancing its brain bioavailability.

Development and In Vitro Evaluation of Controlled Release Viagra® Containing Poloxamer-188 Using Gastroplus™ PBPK Modeling Software for In Vivo Predictions and Pharmacokinetic Assessments

Sildenafil is the active substance in Viagra^® tablets, which is approved by the FDA to treat sexual dysfunction in men. Poor solubility and short half-life, however, can limit the span of its effectiveness. Therefore, this study focused on an oral controlled release matrix system with the aim to improve solubility, control the drug release, and sustain the duration of drug activity. The controlled release matrices were prepared with poloxamer-188, hydroxypropyl methylcellulose, and magnesium stearate. Various formulations of different ratios were developed, evaluated in vitro, and assessed in silico. Poloxamer-188 appeared to have a remarkable influence on the release profile of sildenafil citrate. In general, the rate of drug release decreased as the amount of polymer was gradually increased in the matrix system, achieving a maximum release period over 12 h. The in silico assessment by using the GastroPlus™ PBPK modeling software predicted a significant variation in C_max, t_max, t_1/2, and AUC_0-t among the formulations. In conclusion, the combination of polymers in matrix systems can have substantial impact on controlling and modifying the drug release pattern.

Two-step in vitro-in vivo correlations: Deconvolution and convolution methods, which one gives the best predictability? Comparison with one-step approach

Finding predictive dissolution tests and valid IVIVCs are essential activities in generic industry, as they can be used as substitutes of human bioequivalence studies. IVIVCs can be developed by two different strategies: a one-step approach or a two-step approach. The objectives of this work were to compare different deconvolution and convolution methods used in the development of two-step level A IVIVCs and to study if the relationship between the in vitro dissolution rate and the in vivo dissolution rate should guide the decision between using a two-step approach or a one-step approach during the development of a new IVIVC. When the in vitro and the in vivo dissolution rates had a linear relationship, valid and biopredictive two-step IVIVCs were obtained, although there was not a combination of deconvolution and convolution methods that could be named as the best one, as long as all the prediction errors for any combination were within the limits. It was not possible to obtain a valid two-step IVIVC when the relationship between dissolution rates was non-linear, but the one-step approach was able to overcome this fact and it gave valid IVIVCs regardless of whether the relationship between dissolution rates was linear or non-linear.

Development of a Multivariate Predictive Dissolution Model for Tablets Coated with Cellulose Ester Blends

The focus of the present investigation was to develop a predictive dissolution model for tablets coated with blends of cellulose acetate butyrate (CAB) 171-15 and cellulose acetate phthalate (C-A-P) using the design of experiment and chemometric approaches. Diclofenac sodium was used as a model drug. Coating weight gain (X₁, 5, 7.5 and 10%) and CAB 171-15 percentage (X₂, 33.3, 50 and 66.7%) in the coating composition relative to C-A-P and were selected as independent variables by full factorial experimental design. The responses monitored were dissolution at 1 (Y₁), 8 (Y₂), and 24 (Y₃) h. Statistically significant (p < 0.05) effects of X₁ on Y₁ and X₂ on Y₁, Y_2, and Y₃ were observed. The models showed a good correlation between actual and predicted values as indicated by the correlation coefficients of 0.964, 0.914, and 0.932 for Y₁, Y_2, and Y₃, respectively. For the chemometric model development, the near infrared spectra of the coated tablets were collected, and partial least square regression (PLSR) was performed. PLSR also showed a good correlation between actual and model predicted values as indicated by correlation coefficients of 0.916, 0.964, and 0.974 for Y₁, Y₂, and Y₃, respectively. Y₁, Y_2, and Y₃ predicted values of the independent sample by both approaches were close to the actual values. In conclusion, it is possible to predict the dissolution of tablets coated with blends of cellulose esters by both approaches.

Quality by Design Based Formulation Study of Meloxicam-Loaded Polymeric Micelles for Intranasal Administration

Our study aimed to develop an “ex tempore” reconstitutable, viscosity enhancer- and preservative-free meloxicam (MEL)-loaded polymeric micelle formulation, via Quality by Design (QbD) approach, exploiting the nose-to-brain pathway, as a suitable tool in the treatment of neuroinflammation. The anti-neuroinflammatory effect of nose-to-brain NSAID polymeric micelles was not studied previously, therefore its investigation is promising. Critical product parameters, encapsulation efficiency (89.4%), Z-average (101.22 ± 2.8 nm) and polydispersity index (0.149 ± 0.7) and zeta potential (−25.2 ± 0.4 mV) met the requirements of the intranasal drug delivery system (nanoDDS) and the targeted profile liquid formulation was transformed into a solid preservative-free product by freeze-drying. The viscosity (32.5 ± 0.28 mPas) and hypotonic osmolality (240 mOsmol/L) of the reconstituted formulation provides proper and enhanced absorption and probably guarantees the administration of the liquid dosage form (nasal drop and spray). The developed formulation resulted in more than 20 times faster MEL dissolution rate and five-fold higher nasal permeability compared to starting MEL. The prediction of IVIVC confirmed the great potential for in vivo brain distribution of MEL. The nose-to-brain delivery of NSAIDs such as MEL by means of nanoDDS as polymeric micelles offers an innovative opportunity to treat neuroinflammation more effectively.

In Vivo Predictive Dissolution (IPD) for Carbamazepine Formulations: Additional Evidence Regarding a Biopredictive Dissolution Medium

The aim of the present study was to bring additional evidence regarding a biopredictive dissolution medium containing 1% sodium lauryl sulphate (SLS) to predict the in vivo behavior of carbamazepine (CBZ) products. Twelve healthy volunteers took one immediate release (IR) dose of either test and reference formulations in a bioequivalence study (BE). Dissolution profiles were carried-out using the medium. Level A in vitro–in vivo correlations (IVIVC) were established using both one-step and two-step approaches as well as exploring the time-scaling approach to account for the differences in dissolution rate in vitro versus in vivo. A detailed step by step calculation was provided to clearly illustrate all the procedures. The results show additional evidence that the medium containing 1% SLS can be classified as a universal biopredictive dissolution tool, and that both of the approaches used to develop the IVIVC (one and two-steps) provide good in vivo predictability. Therefore, this biopredictive medium could be a highly relevant tool in Latin-American countries to ensure and check the quality of their CBZ marketed products for which BE studies were not requested by their regulatory health authorities.