Statistical approaches to evaluate in vitro dissolution data against proposed dissolution specifications

In vitro dissolution testing is a regulatory required critical quality measure for solid dose pharmaceutical drug products. Setting the acceptance criteria to meet compendial criteria is required for a product to be filed and approved for marketing. Statistical approaches for analyzing dissolution data, setting specifications and visualizing results could vary according to product requirements, company's practices, and scientific judgements. This paper provides a general description of the steps taken in the evaluation and setting of in vitro dissolution specifications at release and on stability.

Preparation and Characterization of Theophylline Controlled Release Matrix System Incorporating Poloxamer 407, Stearyl Alcohol, and Hydroxypropyl Methylcellulose: A Novel Formulation and Development Study

BACKGROUND

Theophylline (THN), a bronchodilator with potential applications in emerging conditions like COVID-19, requires a controlled-release delivery system due to its narrow therapeutic range and short half-life. This need is particularly crucial as some existing formulations demonstrate impaired functionality. This study aims to develop a new 12-h controlled-release matrix system (CRMS) in the form of a capsule to optimize dosing intervals.

METHODS

CRMSs were developed using varying proportions of poloxamer 407 (P-407), stearyl alcohol (STA), and hydroxypropyl methylcellulose (HPMC) through the fusion technique. Their in vitro dissolution profiles were then compared with an FDA-approved THN drug across different pH media. The candidate formulation underwent characterization using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Additionally, a comprehensive stability study was conducted.

RESULTS

In vitro studies showed that adjusting the concentrations of excipients effectively controlled drug release. Notably, the CRMS formulation 15 (CRMS-F15), which was composed of 30% P-407, 30% STA, and 10% HPMC, closely matched the 12 h controlled-release profile of an FDA-approved drug across various pH media. Characterization techniques verified the successful dispersion of the drug within the matrix. Furthermore, CRMS-F15 maintained a consistent controlled drug release and demonstrated stability under a range of storage conditions.

CONCLUSIONS

The newly developed CRMS-F15 achieved a 12 h controlled release, comparable to its FDA-approved counterpart.

Digitalizing the TIM-1 Model Using Computational Approaches─Part Two: Digital TIM-1 Model in GastroPlus

A TIM-1 model is an in vitro gastrointestinal (GI) simulator considering crucial physiological parameters that will affect the in vivo drug release process. The outcome of these experiments can indicate the critical bioavailability attributes (CBAs) that will impact the fraction absorbed in vivo. The model is widely used in the nonclinical stage of drug product development to assess the bioaccessible fraction of drugs for numerous candidate formulations. In this work, we developed a digital TIM-1 model in the GastroPlus platform. In a first step, we performed validation experiments to assess the luminal concentrations and bioaccessible fractions for two marker compounds. The digital TIM-1 was able to adequately reflect the luminal concentrations and bioaccessible fractions of these markers under different prandial conditions, confirming the appropriate integration of mass transfer in the TIM-1 model. In a second set of experiments, a case example with PF-07059013 was performed, where luminal concentrations and bioaccessible fractions were predicted for 200 and 1000 mg doses under fasted and achlorhydric conditions. Experimental and simulated data pointed out that the achlorhydric effect was more pronounced at the 1000 mg dose, showing a solubility-limited dissolution and, consequently, decreased bioaccessible fraction. Toward future applications, the digital TIM-1 model will be thoroughly applied to explore a link between in vitro and in vivo outcomes based on more case examples with model compounds with the access of TIM-1 and plasma data. Ideally, this digital TIM-1 can be directly used in GastroPlus to explore an in vitro-in vivo correlation (IVIVC) between the fraction dissolved (digital TIM-1 settings) and the fraction absorbed (human PBPK settings).

Digitalizing the TIM-1 Model using Computational Approaches-Part One: TIM-1 Data Explorer

The TIM-1 gastrointestinal model is one of the most advanced in vitro systems currently available for biorelevant dissolution testing. This technology, the initial version of which was developed nearly 30 years ago and has been subject to a number of significant updates over this period, simulates the dynamic environment of the human gastrointestinal tract, including pH, transfer times, secretion of bile, enzymes, and electrolytes. In the pharmaceutical industry, the TIM-1 system is used to support drug product design and provide a biopredictive assessment of drug product performance. Typically, the bioaccessibility data sets generated by TIM-1 experiments are used to qualitatively compare formulation performance, and the use of bioaccessibility data as inputs for physiologically based pharmacokinetic (PBPK) modeling for quantitative predictions is limited. To expand the utility of the TIM-1 model beyond standard bioaccessibility measurements (which define the fraction available for absorption), we have developed a computational tool, TIM-1 Data Explorer, to describe the fluid and mass balance within the TIM-1 system. The use of this tool allows a detailed inspection and in-depth interpretation of the experimental data. In addition to mass balance calculation, this model also can be used to describe the critical processes a drug substance would undergo during a TIM-1 experiment, such as dissolution, precipitation on transfer from the stomach to duodenum, and redissolution. The TIM-1 Data Explorer was validated in two case studies. In the first case study with paracetamol, we have shown the ability of the simulator to adequately describe mass transfer events within the TIM-1 system, and in the second study with a weakly basic in-house compound, PF-07059013, the TIM-1 Data Explorer was successfully used to describe dissolution and precipitation processes.

Development and In vitro Evaluation of Aceclofenac Buccal Film

AIM

This study aimed to formulate and characterize aceclofenac buccal film formulations made of different polymers and evaluate the effects of polymer type on buccal film properties.

MATERIALS AND METHODS

Five polymer types, namely hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (SCMC), polyvinyl alcohol (PVA), Eudragit S100, and Eudragit SR100, were used to prepare aceclofenac buccal film formulation either separately or combined by solvent-casting method. These formulations were evaluated in terms of physical appearance, folding test, film weight and thickness, drug content, percentage of elongation, moisture uptake, water vapor permeability, and in vitro drug release.

RESULTS

The addition of Eudragit polymer in most of the produced buccal films was unacceptable with low folding endurance. However, the dissolution profile of buccal films made from PVA and Eudragit SR100 provided a controlled drug release profile.

CONCLUSION

Buccal films can be formulated using different polymers either individually or in combination to obtain the drug release profile required to achieve a desired treatment goal. Furthermore, the property of the buccal films depends on the type and concentration of the polymer used.

Application of a Customised Franz-Type Cell Coupled with HPTLC to Monitor the Timed Release of Bioactive Components in Complex Honey Matrices

The aim of this study was to assess the release profile of components in five different honeys (a New Zealand Manuka and two Western Australian honeys, a Jarrah honey and a Coastal Peppermint honey) and their corresponding honey-loaded gel formulations using a custom-designed Franz-type diffusion cell in combination with High-Performance Thin-Layer Chromatography (HPTLC). To validate the suitability of the customised setup, release data using this new approach were compared with data obtained using a commercial Franz cell apparatus, which is an established analytical tool to monitor the release of active ingredients from topical semisolid products. The release profiles of active compounds from pure honey and honey-loaded formulations were found to be comparable in both types of Franz cells. For example, when released either from pure honey or its corresponding pre-gel formulation, the percentage release of two Jarrah honey constituents, represented by distinct bands at RF 0.21 and 0.53 and as analysed by HPTLC, was not significantly different (p = 0.9986) at 12 h with over 99% of these honey constituents being released in both apparatus. Compared to the commercial Franz diffusion cell, the customised Franz cell offers several advantages, including easy and convenient sample application, the requirement of only small sample quantities, a large diffusion surface area, an ability to analyse 20 samples in a single experiment, and lower cost compared to purchasing a commercial Franz cell. Thus, the newly developed approach coupled with HPTLC is conducive to monitor the release profile of minor honey constituents from pure honeys and honey-loaded semisolid formulations and might also be applicable to other complex natural-product-based products.

Integration of Biorelevant Pediatric Dissolution Methodology into PBPK Modeling to Predict In Vivo Performance and Bioequivalence of Generic Drugs in Pediatric Populations: a Carbamazepine Case Study

This study investigated the impact of gastro-intestinal fluid volume and bile salt (BS) concentration on the dissolution of carbamazepine (CBZ) immediate release (IR) 100 mg tablets and to integrate these in vitro biorelevant dissolution profiles into physiologically based pharmacokinetic modelling (PBPK) in pediatric and adult populations to determine the biopredictive dissolution profile. Dissolution profiles of CBZ IR tablets (100 mg) were generated in 50-900 mL biorelevant adult fasted state simulated gastric and intestinal fluid (Ad-FaSSGF and Ad-FaSSIF), also in three alternative compositions of biorelevant pediatric FaSSGF and FaSSIF medias at 200 mL. This study found that CBZ dissolution was poorly sensitive to changes in the composition of the biorelevant media, where dissimilar dissolution (F2 = 46.2) was only observed when the BS concentration was changed from 3000 to 89 μM (Ad-FaSSIF vs Ped-FaSSIF 50% 14 BS). PBPK modeling demonstrated the most predictive dissolution volume and media composition to forecast the PK was 500 mL of Ad-FaSSGF/Ad-FaSSIF media for adults and 200 mL Ped-FaSSGF/FaSSIF media for pediatrics. A virtual bioequivalence simulation was conducted by using Ad-FaSSGF and/or Ad-FaSSIF 500 mL or Ped-FaSSGF and/or Ped-FaSSIF 200 mL dissolution data for CBZ 100 mg (reference and generic test) IR product. The CBZ PBPK models showed bioequivalence of the product. This study demonstrates that the integration of biorelevant dissolution data can predict the PK profile of a poorly soluble drug in both populations. Further work using more pediatric drug products is needed to verify biorelevant dissolution data to predict the in vivo performance in pediatrics.

Instant Formulation of Inhalable Beclomethasone Dipropionate-Gamma-Cyclodextrin Composite Particles Produced Using Supercritical Assisted Atomization

Medical composites derived from Gamma-cyclodextrin (γ-CD) and beclomethasone dipropionate-gamma-cyclodextrin (BDP-γ-CD) are synthesized over supercritical-assisted atomization (SAA) herein. Carbon dioxide, which serves the dual function of spraying medium and co-solute, is incorporated in this process along with the ethanolic solvent. Results indicate that, for fine spherical particles, optimized aerosol performance could be obtained with 50.0% (w/w) ethanolic solvent, precipitator, and saturator at 373.2 K and 353.2 K, respectively, and carbon dioxide-to-γ-CD flow ratio of 1.8 in the presence of 10 wt% leucine (LEU) as dispersion enhancer. It is also noted that γ-CD solution at low concentration typically renders better aerosol performance of the particles. During drug particle-derivation, the solubility of drug BDP elevated considerably due to the formation of inclusion complexes, further assisted by the ethanolic solvent which increases the lipophilicity of BDP. Meanwhile, the in vitro aerosolization and dissolution performance of drug composites derived from varied γ-CD-to-BDP mass ratio (Z) were also evaluated. It was found that high Z promises higher fine particle fraction in the obtained drug composite while the dissolution rate of active ingredient (BDP) exhibits positive correlation to the content of water-soluble excipient (γ-CD) in the formulation. This study offers a new avenue for instant drug formulation with promising pulmonary delivery over the SAA technique.

Long-Acting Injectable Aqueous Suspensions-Summary From an AAPS Workshop

Through many years of clinical application of long-acting injectables, there is clear proof that this type of formulation does not just provide the patient with convenience, but more importantly a more effective treatment of the medication provided. The formulation approach therefore contains huge untapped potential to improve the quality of life of many patients with a variety of different diseases. This review provides a summary of some of the central talks provided at the workshop with focus on aqueous suspensions and their use as a long-acting injectable. Elements as formulation, manufacturing, in vitro dissolution methods, in vitro and in vivo correlation, in silico modelling provide an insight into some of the current understandings, learnings, and not least gaps in the field.

Establishment of In Vitro Dissolution Based on Similarity with In Vivo Dissolution: A Case Study on Aripiprazole

In vitro dissolution that predicts the in vivo performance of solid preparations is extremely important in formulation optimization. Fraction absorbed (F_a) has been used to screen in vitro dissolution protocols based on the idea of in vitro-in vivo correlation (IVIVC) but failed to increase the success rate due to the inaccuracy of the F_a. The essence of IVIVC is the correlation between in vitro dissolution and in vivo dissolution. We tried to establish in vitro dissolution protocol via similarity with in vivo dissolution using aripiprazole (APZ) as a model drug. Hybrid APZ crystals (APZ-HCs) were prepared by physically embedding aggregation-caused quenching (ACQ) fluorophores inside the lattice to measure the in vivo dissolution. The process did not change the physicochemical properties and crystallinity of APZ. The fluorophore illuminated APZ crystals but was quenched upon dissolution of APZ-HCs in aqueous media, enabling monitoring intact APZ-HCs in real-time. The good correlation between fluorescent quenching and dissolution of APZ-HCs justified reliable quantification of intact APZ crystals. The residual percentage of fluorescence intensity in rats treated by APZ-HCs was recorded with time, which was converted to in vivo dissolution by the difference from 100%. The in vivo dissolution was validated with the F_a. The in vitro dissolution profile of APZ was set up via a similarity factor larger than 50 in comparison with the in vivo dissolution. The study provides a novel idea and method to establish in vitro dissolution protocol.

Virtual Bioequivalence Assessment of Elagolix Formulations Using Physiologically Based Pharmacokinetic Modeling

In lieu of large bioequivalence studies and exposing healthy postmenopausal women to additional drug exposure for elagolix coadministered with hormonal add-back therapy, physiologically based pharmacokinetic (PBPK) modeling was used with in vitro dissolution data to test for virtual bioequivalence. For endometriosis, elagolix is approved at doses of 150 mg once daily and 200 mg twice daily as a tablet. As a combination therapy, two individual tablets, consisting of an elagolix tablet and an estradiol/norethindrone acetate 1/0.5 mg (E2/NETA) tablet, were utilized in Phase 3 endometriosis trials. However, the commercial combination drug products consist of a morning capsule (containing an elagolix tablet and E2/NETA tablet as a fixed-dose combination capsule, AM capsule) and an evening capsule (consisting of an elagolix tablet, PM capsule). In vitro dissolution profiles were dissimilar for the tablet and capsule formulations; thus, in vivo bioequivalence studies or a bioequivalence waiver would have been required. To simulate virtual cross-over, bioequivalence trials, in vitro dissolution data was incorporated into a previously verified PBPK model. The updated PBPK model was externally validated using relevant bioequivalence study data. Based on results of the virtual bioequivalence simulations, the commercial drug product capsules met the bioequivalence criteria of 0.80-1.25 when compared to the reference tablets. This was a novel example where PBPK modeling was utilized along with in vitro dissolution data to demonstrate virtual bioequivalence in support of a regulatory bioequivalence waiver.

Synthesis of Microwave Functionalized, Nanostructured Polylactic Co-Glycolic Acid (nfPLGA) for Incorporation into Hydrophobic Dexamethasone to Enhance Dissolution

The low solubility and slow dissolution of hydrophobic drugs is a major challenge for the pharmaceutical industry. In this paper, we present the synthesis of surface-functionalized poly(lactic-co-glycolic acid) (PLGA) nanoparticles for incorporation into corticosteroid dexamethasone to improve its in vitro dissolution profile. The PLGA crystals were mixed with a strong acid mixture, and their microwave-assisted reaction led to a high degree of oxidation. The resulting nanostructured, functionalized PLGA (nfPLGA), was quite water-dispersible compared to the original PLGA, which was non-dispersible. SEM-EDS analysis showed 53% surface oxygen concentration in the nfPLGA compared to the original PLGA, which had only 25%. The nfPLGA was incorporated into dexamethasone (DXM) crystals via antisolvent precipitation. Based on SEM, RAMAN, XRD, TGA and DSC measurements, the nfPLGA-incorporated composites retained their original crystal structures and polymorphs. The solubility of DXM after nfPLGA incorporation (DXM-nfPLGA) increased from 6.21 mg/L to as high as 87.1 mg/L and formed a relatively stable suspension with a zeta potential of -44.3 mV. Octanol-water partitioning also showed a similar trend as the logP reduced from 1.96 for pure DXM to 0.24 for DXM-nfPLGA. In vitro dissolution testing showed 14.0 times higher aqueous dissolution of DXM-nfPLGA compared to pure DXM. The time for 50% (T₅₀) and 80% (T₈₀) of gastro medium dissolution decreased significantly for the nfPLGA composites; T₅₀ reduced from 57.0 to 18.0 min and T₈₀ reduced from unachievable to 35.0 min. Overall, the PLGA, which is an FDA-approved, bioabsorbable polymer, can be used to enhance the dissolution of hydrophobic pharmaceuticals and this can lead to higher efficacy and lower required dosage.

Physiologically Based Pharmacokinetics Modeling in Biopharmaceutics: Case Studies for Establishing the Bioequivalence Safe Space for Innovator and Generic Drugs

For successful oral drug development, defining a bioequivalence (BE) safe space is critical for the identification of newer bioequivalent formulations or for setting of clinically relevant in vitro specifications to ensure drug product quality. By definition, the safe space delineates the dissolution profile boundaries or other drug product quality attributes, within which the drug product variants are anticipated to be bioequivalent. Defining a BE safe space with physiologically based biopharmaceutics model (PBBM) allows the establishment of mechanistic in vitro and in vivo relationships (IVIVR) to better understand absorption mechanism and critical bioavailability attributes (CBA). Detailed case studies on how to use PBBM to establish a BE safe space for both innovator and generic drugs are described. New case studies and literature examples demonstrate BE safe space applications such as how to set in vitro dissolution/particle size distribution (PSD) specifications, widen dissolution specification to supersede f2 tests, or application toward a scale-up and post-approval changes (SUPAC) biowaiver. A workflow for detailed PBBM set-up and common clinical study data requirements to establish the safe space and knowledge space are discussed. Approaches to model in vitro dissolution profiles i.e. the diffusion layer model (DLM), Takano and Johnson models or the fitted PSD and Weibull function are described with a decision tree. The conduct of parameter sensitivity analyses on kinetic dissolution parameters for safe space and virtual bioequivalence (VBE) modeling for innovator and generic drugs are shared. The necessity for biopredictive dissolution method development and challenges with PBBM development and acceptance criteria are described.

Exploring a Bioequivalence Failure for Silodosin Products Due to Disintegrant Excipients

Some years ago, excipients were considered inert substances irrelevant in the absorption process. However, years of study have demonstrated that this belief is not always true. In this study, the reasons for a bioequivalence failure between two formulations of silodosin are investigated. Silodosin is a class III drug according to the Biopharmaceutics Classification System, which has been experimentally proven by means of solubility and permeability experiments. Dissolution tests have been performed to identify conditions concordant with the non-bioequivalent result obtained from the human bioequivalence study and it has been observed that paddles at 50 rpm are able to detect inconsistent differences between formulations at pH 4.5 and pH 6.8 (which baskets at 100 rpm are not able to do), whereas the GIS detects differences at the acidic pH of the stomach. It has also been observed that the differences in excipients between products did not affect the disintegration process, but disintegrants did alter the permeability of silodosin through the gastrointestinal barrier. Crospovidone and povidone, both derivatives of PVP, are used as disintegrants in the test product, instead of the pregelatinized corn starch used in the reference product. Permeability experiments show that PVP increases the absorption of silodosin-an increase that would explain the greater C_max observed for the test product in the bioequivalence study.

Co-amorphous Drug Delivery Systems: a Review of Physical Stability, In Vitro and In Vivo Performance

Over the past few decades, co-amorphous solids have been used as a promising approach for delivering poorly water-soluble drugs. Co-amorphous solids, comprising pharmacologically relevant drug substances or excipients, improve physical stability, solubility, dissolution, and bioavailability compared with single amorphous ingredients. In this review, we have summarized recent advances in physical stability and in vitro and in vivo performances of co-amorphous solids. We have highlighted the role of molar ratio, molecular interaction, and mobility that affects the physical stability of co-amorphous solids. This review delves deep as to how co-amorphous solids affect the physicochemical properties in vitro and in vivo. We also described the challenges to the formulation of co-amorphous solids. A better understanding of the mechanisms of the physical stability, in vitro and in vivo performance of co-amorphous solids, and proper selection of the co-former is likely to expedite the development of robust co-amorphous-based pharmaceutical formulations and can address the challenges associated with the delivery of poorly soluble drugs.

Development of an In Vitro Drug Release Method to Enable In Vitro-In Vivo Correlation of Potassium Chloride Extended-Release Tablets

An in vitro drug release test was developed to establish a level A in vitro-in vivo correlation (IVIVC) for predicting the in vivo performance of potassium chloride extended-release (ER) matrix tablets. Three ER formulations of potassium chloride with different in vitro release rates were designed using the USP dissolution test, and their urinary pharmacokinetic profiles were evaluated in healthy subjects. Due to the lack of IVIVC with the USP method, experiments were designed to investigate the effects of in vitro test conditions on drug release in order to match in vitro drug release with in vivo behaviors of different formulations. The evaluated in vitro variables included the type of USP apparatus, surfactant, and ionic strength of the dissolution medium. Based on the study findings and data analysis, a discriminatory drug release method was successfully developed that enabled the establishment and validation of a level A IVIVC model of the potassium chloride ER tablet using urinary pharmacokinetic data. This method uses USP apparatus I at 50 rpm in 900 mL of 150 mM NaCl solution containing 40 mM sodium dodecyl sulfate at 37 °C. The current study highlights the value of investigating test conditions in developing a predictive in vitro test method for establishing IVIVC.

Immediate Release Formulation of Inhaled Beclomethasone Dipropionate-Hydroxypropyl-Beta-Cyclodextrin Composite Particles Produced Using Supercritical Assisted Atomization

In this study, the enhanced solubilization performance of a poorly soluble drug, beclomethasone dipropionate (BDP), was investigated using hydroxypropyl-β-cyclodextrin (HP-β-CD) and ethanol. The enhanced solubility of the drug was determined using the phase solubility method and correlated as a function of both HP-β-CD and ethanol concentrations. The effective progress of drug solubility originated from the formation of cyclodextrin and BDP inclusion complexes and increase in the lipophilicity of the medium, by aqueous ethanol, for hydrophobic BDP. BDP and HP-β-CD composite particles were produced using supercritical assisted atomization (SAA) with carbon dioxide as the spraying medium, 54.2% (w/w) aqueous ethanol as the solvent, and an optimal amount of the dispersion enhancer leucine. The effect of the mass ratio of HP-β-CD to BDP (Z) on the in vitro aerosolization and in vitro dissolution performance of BDP-HP-β-CD composite particles was evaluated. The aerosolization performance showed that the fine particles fraction (FPF) of the composite particles increased with increasing mass ratio. The water-soluble excipient (HP-β-CD) effectively enhance the dissolution rate of BDP from composite particles. This study suggests that BDP-HP-β-CD composite particles produced using SAA can be employed in immediate-release drug formulations for pulmonary delivery.

A Novel Aminomethacrylate-Based Copolymer for Solubility Enhancement-From Radical Polymer Synthesis to Manufacture and Characterization of Amorphous Solid Dispersions

The present study covers the synthesis, purification and evaluation of a novel aminomethacrylate-based copolymer in terms of its suitability for improving the solubility and in vitro release of poorly water-soluble drug compounds. The new copolymer was synthesized by solvent polymerization with radical initiation and by use of a chain transfer agent. Based on its composition, it can be considered as a modified type of dimethylaminoethyl methacrylate-butyl methacrylate-methyl methacrylate "EUDRAGIT^® E PO" (ModE). ModE was specifically developed to provide a copolymer with processing and application properties that exceed those of commercially available (co-)polymers in solubility enhancement technologies where possible. By varying the concentration of the chain transfer agent in the radical polymerization process, the molecular weight of ModE was varied in a range of 173-305 kDa. To evaluate the solubility-enhancing properties of ModE, a series of drug-loaded extrudates were prepared by hot melt extrusion using the novel-as well as several commercially available-(co-)polymers. These extrudates were then subjected to comparative tests for amorphousness, solubility-enhancing properties, storage stability, and drug release. Celecoxib, efavirenz, and fenofibrate were used as model drugs in all experiments. Of all the (co-)polymers included in the study, ModE with a molecular weight of 173 kDa showed the best performance in terms of desired properties and was shown to be particularly suitable for preparing amorphous solid dispersions (ASDs) of the three model drugs, which in a first set of dissolution experiments showed better release behavior under pH conditions of the fasting stomach than higher molecular weight ModE types, as well as a variety of commercially available (co-)polymers. Therefore, the results demonstrate the successful synthesis of a new copolymer, which in future studies will be investigated in more detail for universal application in the field of solubility enhancement.

Development of biocompatible nanoparticles of tizanidine hydrochloride in orodispersible films: In vitro characterization, ex vivo permeation and cytotoxic study on carcinoma cells

BACKGROUND

The main limitations of the therapeutic effectiveness of tizanidine hydrochloride (TNZ) are its low bioavailability due to its tendency to undergo first-pass metabolism and short biological half-life. These factors make it an ideal candidate for formulating orally disintegrating films.

METHODS

The fast-dissolving film of TNZ HCl was prepared by the solvent-casting method and characterized using scanning electron microscopy, FTIR and XRD, and evaluated for critical quality attributes for this type of dosage forms such as disintegration time, tensile strength, drug content, dissolution, and ex-vivo permeability. In vitro cytotoxicity studies were also conducted on cancer cell lines to confirm cytotoxic effect.

OBJECTIVE

The present study was aimed to prepare nanoparticles of tizanidine hydrochloride using biodegradable polymers and loading them on orodispersible films to obtain a sustained release dissolution profile with improved permeability and further study the cytotoxicity on A549 lung carcinoma cells, MCF7 breast cancer cells and HOP 92 non-small lung adenocarcinoma cells.

RESULTS

The polymeric matrix containing the drug provided a rapid disintegration time varying between 7±2 and 30±2 seconds, adequate tensile strength between 1.4 and 11.25 N/mm2, and improved permeability through porcine buccal mucosa when compared to the reference product.

CONCLUSION

A study of cytotoxic effect on the MCF-7 breast cancer cells and A549 lung carcinoma cells revealed that tizanidine hydrochloride nanoparticles at 2.3 mg/film exhibited an IC50 value of 65.1 % cytotoxicity on MCF-7, approximately 100% on HOP92, and 83.5 % on A549 lung carcinoma cells, thus paving the way for a new paradigm of research for cytotoxic study on MCF-7, HOP92 and A549 cell lines using the subject drug model prepared as oral films or biodegradable nanoparticles in oral films for site-specific targeting.

In Vitro Dissolution of Na-Ca-P-Oxynitrides

Sodium-calcium-phosphate based oxynitride glasses and glass-ceramics doped with Mg, Si, and Nb were studied in vitro in simulated body fluid (SBF) under static conditions. The release of ions and pH changes up to 7 days of immersion were investigated. The nitrogen incorporation into phosphate glass matrix was found to notably influence in vitro dissolution only of homogenous glasses. Increasing the nitrogen content in the samples decreased the mean mass loss, while the niobate incorporation increased it. The correlation between the nitrogen content and increase in pH of SBF was also observed. The presence of phosphates crystallites was found to support the dissolution process at the beginning step (up to 3 days).

In vitro Comparison of Pancreatic Enzyme Preparations Available in the Indian Market

Purpose

Pancreatic enzyme replacement therapy (PERT) involves exogenous enzyme supplementation and is used in the treatment of pancreatic exocrine insufficiency. Clinical efficacy of PERT preparations is a function of physical properties and release kinetics that vary between commercially available products. In this study, we evaluated the physical properties, in vitro dissolution, and release kinetics of commercially available pancreatic enzyme preparations available in the Indian market.

Methods

Physical properties such as particle size distribution and water content of the capsules were measured by dynamic light scattering and Karl–Fischer titration method, respectively. An analytical procedure based on the European pharmacopoeia (EP) method was used to determine lipase activity, and a modified United States pharmacopoeia (USP)–based method was used for dissolution studies. Enzyme release was ascertained under gastroduodenal conditions in buffered media.

Results

Considerable variations in physical properties such as particle size and water content were observed between pancreatic enzyme preparations. Some preparations failed to meet the labeled lipase content as per USP standards (>90% label claim) and showed inconsistent release behavior (>5% relative standard deviation).

Conclusion

Differences exist between pancreatic enzyme preparations in terms of physical properties, dissolution, and release behavior that can affect their clinical efficacy. The present study suggests, therefore, that these preparations should not be used interchangeably.

Dissolution of Amorphous S53P4 Glass Scaffolds in Dynamic In Vitro Conditions

The silicate-based bioactive glass S53P4 is clinically used in bone regenerative applications in granule form. However, utilization of the glass in scaffold form has been limited by the high tendency of the glass to crystallize during sintering. Here, careful optimization of sintering parameters enabled the manufacture of porous amorphous S53P4 scaffolds with a strength high enough for surgical procedures in bone applications (5 MPa). Sintering was conducted in a laboratory furnace for times ranging from 25 to 300 min at 630 °C, i.e., narrowly below the commencement of the crystallization. The phase composition of the scaffolds was verified with XRD, and the ion release was tested in vitro and compared with granules in continuous flow of Tris buffer and simulated body fluid (SBF). The amorphous, porous S53P4 scaffolds present the possibility of using the glass composition in a wider range of applications.

Development and Characterization of Calcium-Alginate Beads of Apigenin: In Vitro Antitumor, Antibacterial, and Antioxidant Activities

The objective of this work was to develop sustained-release Ca-alginate beads of apigenin using sodium alginate, a natural polysaccharide. Six batches were prepared by applying the ionotropic gelation technique, wherein calcium chloride was used as a crosslinking agent. The beads were evaluated for particle size, drug loading, percentage yield, and in vitro drug release. Particle size was found to decrease, and drug entrapment efficiency was enhanced with an increase in the polymer concentration. The dissolution study showed sustained drug release from the apigenin-loaded alginate beads with an increase in the polymer proportion. Based on the dissolution profiles, BD6 formulation was optimized and characterized for FTIR, DSC, XRD, and SEM, results of which indicated successful development of apigenin-loaded Ca alginate beads. MTT assay demonstrated a potential anticancer effect against the breast cancer MCF-7 cell lines. The antimicrobial activity exhibited effective inhibition in the bacterial and fungal growth rate. The DPPH measurement revealed that the formulation had substantial antioxidant activity, with EC50 value slightly lowered compared to pure apigenin. A stability study demonstrated that the BD6 was stable with similar (f2) drug release profiles in harsh condition. In conclusion, alginate-based beads could be used for sustaining the drug release of poorly water-soluble apigenin while also improving in vitro antitumor, antimicrobial, and antioxidant activity.

Development of Spray-Dried Cyclodextrin-Based Pediatric Anti-HIV Formulations

The human immunodeficiency virus (HIV) impacts up to 37 million people globally, of which 1.8 million are children. To date, there is no cure for HIV, although treatment options such as antiretroviral therapy (ART) are available. ART, which involves a patient taking a combination of antiretrovirals, is being used to treat HIV clinically. Despite the effectiveness of ART, there is currently no palatable pediatric formulation to treat HIV in children, which has hindered patient compliance and overall treatment efficacy. In addition, anti-HIV therapeutics are often poorly water-soluble, and hence have poor bioavailability. In the present study, we developed a pediatric-friendly formulation for anti-HIV therapeutics with improved dissolution characteristics of the therapeutic agents. Lopinavir (LPV) and ritonavir (RTV), available as FDA-approved fixed-dose combination products, were chosen as model ART drugs, and the formulation and processing parameters of spray-dried cyclodextrin (CD)-based LPV and RTV complexes were studied. Results showed that the spray-dried complexes exhibited enhanced dissolution profiles in comparison to pure drugs, particularly spray-dried β-CD complexes, which showed the most favorable dissolution profiles. This current formulation with enhanced dissolution and taste-masking ability through the use of cyclodextrin has the potential to address the unmet need for the development of suitable pediatric formulations.

Evaluation of the In-Vitro Dissolution Permeation Systems 1 (IDAS1) as a potential tool to monitor for unexpected changes in generic medicaments in poorly regulated markets

Panama, like most Latin American countries, has insufficient regulatory safeguards to ensure the safety and efficacy of all pharmaceutical products in the market, a situation that results in a two-tier system, where affluent citizens can afford innovator products while poor citizens must consume 'generics' of uncertain quality. Given that one lot of each drug product is analyzed every five years during registration while commercial lots are not, and since most products are not bioequivalent but simply copies or similars, there is a concern that commercial and registration lots of these 'generics' may not be of the same quality. The objective of this study was to assess the ability of various in vitro quality control tests to detect difference among five amlodipine products available in the Panamanian market: four 'generics', made in various countries, and the innovator, made in Germany and used as reference listed drug in Panama (Pan-RLD). The innovator manufactured in the United States (US-RLD) was used to compare the two RLDs. The Content Uniformity test, 30-min Dissolution test and multiple-pH Dissolution Profiles did not show any difference among the products. However, the in vitro dissolution absorption system 1 (IDAS1) showed a statistically significant difference in the amount dissolved between Pan-RLD and three out of the four 'generics', and significantly lower permeated amount for all the 'generics' compared with Pan-RLD; only US-RLD was similar to Pan-RLD. Thus, IDAS1 showed promise as a potential tool that authorities in weakly regulated markets can use to monitor for possible lot-to-lot product changes, which can help improve the quality of pharmaceutical products available to their entire populations. The significance of the similarity between the innovators made in Germany and the United States and their difference from the 'generics' (manufactured in other countries) is not known but deserves investigation.

An In Vivo Predictive Dissolution Methodology (iPD Methodology) with a BCS Class IIb Drug Can Predict the In Vivo Bioequivalence Results: Etoricoxib Products

The purpose of this study was to predict in vivo performance of three oral products of Etoricoxib (Arcoxia^® as reference and two generic formulations in development) by conducting in vivo predictive dissolution with GIS (Gastro Intestinal Simulator) and computational analysis. Those predictions were compared with the results from previous bioequivalence (BE) human studies. Product dissolution studies were performed using a computer-controlled multicompartmental dissolution device (GIS) equipped with three dissolution chambers, representing stomach, duodenum, and jejunum, with integrated transit times and secretion rates. The measured dissolved amounts were modelled in each compartment with a set of differential equations representing transit, dissolution, and precipitation processes. The observed drug concentration by in vitro dissolution studies were directly convoluted with permeability and disposition parameters from literature to generate the predicted plasma concentrations. The GIS was able to detect the dissolution differences among reference and generic formulations in the gastric chamber where the drug solubility is high (pH 2) while the USP 2 standard dissolution test at pH 2 did not show any difference. Therefore, the current study confirms the importance of multicompartmental dissolution testing for weak bases as observed for other case examples but also the impact of excipients on duodenal and jejunal in vivo behavior.

Physicomechanical, stability, and pharmacokinetic evaluation of aceclofenac dimethyl urea cocrystals

Poor physicomechanical properties and limited aqueous solubility restrict the bioavailability of aceclofenac when given orally. To improve its above properties, aceclofenac (ACE) was cocrystallized with dimethyl urea (DMU) in 1:2 molar ratio by dry and solvent assisted grinding. The cocrystals were characterized by ATR-FTIR, DSC, and PXRD, and their surface morphology was studied by SEM. There was enhancement in intrinsic dissolution rate (IDR) (~eight- and ~fivefold in cocrystals prepared by solvent assisted grinding (SAG) and solid state grinding (SSG), respectively, in 0.1 N HCl, pH 1.2) and similarly (~3.42-fold and ~1.20-fold in phosphate buffer, pH 7.4) as compared to pure drug. Additionally, mechanical properties were assessed by tabletability curves. The tensile strength of ACE was < 1 MPa in contrast to the cocrystal tensile strength (3.5 MPa) which was ~1.98 times higher at 6000 psi. The tablet formulation of cocrystal by direct compression displayed enhanced dissolution profile (~36% in 0.1 N HCl, pH 1.2, and ~100% in phosphate buffer, pH 7.4) in comparison to physical mixture (~ 30% and ~ 80%) and ACE (~18% and ~50%) after 60 min, respectively. Stability studies of cocrystal tablets for 3 months indicated a stable formulation. Pharmacokinetic studies were performed by using rabbit model. The AUC_0-∞ (37.87±1.3 μgh/ml) and C_max (6.94±2.94 μg/ml) of the selected cocrystal C1 prepared by SAG were significantly enhanced (p < 0.05) and were ~3.43 and ~1.63-fold higher than that of ACE. In conclusion, new cocrystal of ACE-DMU was successfully prepared with improved tabletability, in vitro and in vivo properties.

Simulation of respiratory tract lining fluid for in vitro dissolution study

Introduction: Drug particles inhaled via the respiratory system must first dissolve in the respiratory tract lining fluid (RTLF) that lies on the surfaces of airways and alveoli, so that they are absorbed and have therapeutic action. Artificial simulated RTLFs are often used for in vitro dissolution studies to determine the solubility and dissolution of inhaled drug particles. Such studies can be used to predict bioavailability minimizing the requirement for in vivo studies. Numerous studies have been conducted to develop bio-relevant simulated RTLFs; however, to date, there is no singular simulated RTLF that closely resembles human RTLF.Areas covered: This review focuses on the composition of natural and simulated RTLFs and their use in in vitro dissolution studies.Expert opinion: There is variation in the composition and thickness of RTLF along the respiratory tract. Identification of the actual concentration of components of endogenous RTLF present in different areas of the respiratory tract helps in the development of region-specific simulated RTLFs. It is recommended that region-specific simulated RTLFs can be prepared by varying concentration of major RTLF components like mucus/gel simulants, lipids/surfactants, peptides/proteins, and inorganic/organic salts.

An In Vitro-In Vivo Simulation Approach for the Prediction of Bioequivalence

The aim of this study was to develop a new in vitro–in vivo simulation (IVIVS) approach in order to predict the outcome of a bioequivalence study. The predictability of the IVIVS procedure was evaluated through its application in the development process of a new generic product of amlodipine/irbesartan/hydrochlorothiazide. The developed IVIVS methodology is composed of three parts: (a) mathematical description of in vitro dissolution profiles, (b) mathematical description of in vivo kinetics, and (c) development of joint in vitro–in vivo simulations. The entire programming was done in MATLAB^® and all created scripts were validated through other software. The IVIVS approach can be implemented for any number of subjects, clinical design, variability and can be repeated for thousands of times using Monte Carlo techniques. The probability of success of each scenario is recorded and finally, an overall assessment is made in order to select the most suitable batch. Alternatively, if the IVIVS shows reduced probability of BE success, the R&D department is advised to reformulate the product. In this study, the IVIVS approach predicted successfully the BE outcome of the three drugs. During the development of generics, the IVIVS approach can save time and expenses.

Clinical Pharmacokinetic Evaluation of Optimized Liquisolid Tablets as a Potential Therapy for Male Sexual Dysfunction

The study aimed at developing a liquisolid tablet (LST) containing tadalafil (TDL) and dapoxetine (DPX) with improved bioavailability as a potential therapy for male sexual dysfunction. A mixture of nonvolatile solvents, namely PEG 200 and Labrasol®, was utilized to prepare LSTs that were assessed for their quality characteristics. The Box–Behnken design (BBD) was employed to statistically explore the effect of the formulation factors on the quality attributes of LSTs. Furthermore, an in vivo pharmacokinetic study was carried out for the optimized LST in comparison with the marketed tablets on healthy human volunteers. The optimized LST revealed acceptable quality limits with enhanced dissolution for both APIs. The pharmacokinetic parameters after oral administration of the optimized LST indicated that the Cmax of TDL in LSTs was 122.61 ng/mL within 2h compared to the marketed tablets, which reached 91.72 ng/mL after 3 h, indicating the faster onset of action. The AUC was improved for TDL in LST (4484.953 vs. 2994.611 ng/mL∙h in the marketed tablet) and DPX in LST (919.633 vs. 794.699 ng/mL∙h in the marketed tablet). This enhancement in bioavailability potentially minimizes the associated side effects and improves the treatment of male sexual dysfunction, particularly for diabetic patients.

Stable solid dispersion of lurasidone hydrochloride with augmented physicochemical properties for the treatment of schizophrenia and bipolar disorder

Crystalline solid dispersion of lurasidone hydrochloride (LH) was made with various polar and non-polar small molecules to overcome the poor aqueous solubility issue. LH-Glutathione (GSH) solid dispersion in 1:1 ratio was prepared by co-grinding method and characterized by using differential scanning calorimetry (DSC), powder X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. GSH acts as antioxidant and reported for anti-schizophrenic activity may provide synergistic action with LH or reduce the side effects. LH in LH-GSH solid dispersion (SD) has shown improvement in solubility by 7.9 folds than plain drug which translated in terms of improved dissolution rate by two-folds. The in vitro dissolution results showed maximum dissolution rate with LH-GSH SD (97.85 ± 2.40%) compared to plain drug (50.5 ± 3.02%) at 15 min (t₁₅ min, %) and thus, satisfying criteria of immediate release dosage form. DSC and FTIR data confirmed the stability of LH-GSH SD for 3 months at accelerated stability condition (40 ± 2°C and 75 ± 5% RH). The prepared LH-GSH SD can be used as a tool to target dual problems that is, enhanced physicochemical properties along with possible management of disorder which could be due to synergism with co-administered GSH. This approach is thought to be efficiently providing the relief to the psychological patients.

Simulation of oral absorption from non-bioequivalent dosage forms of the salt of raltegravir, a poorly soluble acidic drug, using a physiologically based biopharmaceutical modeling (PBBM) approach

Non-bioequivalent plasma concentration profiles among different dosage forms of the salt of raltegravir, a poorly soluble acidic drug, were investigated using biorelevant in vitro testing combined with the commercial in silico software, Simcyp®. A suspension and a tablet dosage forms of raltegravir potassium were selected as the test formulations. While dissolution from the suspension was rapid, dissolution from the tablets was slow and delayed by pre-exposure to an acidic environment. Although the tablet was expected to have complex in vivo performance, plasma concentration profiles were successfully simulated when gastric emptying was taken into account as a key physiological factor in in vitro and in silico trials. The effect of pre-exposure to acid in the stomach on dissolution behavior in the intestine was estimated by two-stage in vitro dissolution testing. Based on these results, theoretical in vivo dissolution profiles for different gastric emptying times were inputted into the in silico model and plasma concentration profiles were simulated taking the distribution of individual gastric emptying times into account. The in vitro and in silico method presented in this report would be a practical approach to simulate oral absorption from various formulations of poorly soluble weak acids and their salts.

In Vivo Predictive Dissolution Testing of Montelukast Sodium Formulations Administered with Drinks and Soft Foods to Infants

In vitro dissolution testing conditions that reflect and predict in vivo drug product performance are advantageous, especially for the development of paediatric medicines, as clinical testing in this population is hindered by ethical and technical considerations. The aim of this study was to develop an in vivo predictive dissolution test in order to investigate the impact of medicine co-administration with soft food and drinks on the dissolution performance of a poorly soluble compound. Relevant in vitro dissolution conditions simulating the in vivo gastrointestinal environment of infants were used to establish in vitro-in vivo relationships with corresponding in vivo data. Dissolution studies of montelukast formulations were conducted with mini-paddle apparatus on a two-stage approach: infant fasted-state simulated gastric fluid (Pi-FaSSGF; for 1 h) followed by either infant fasted-state or infant fed-state simulated intestinal fluid (FaSSIF-V2 or Pi-FeSSIF, respectively; for 3 h). The dosing scenarios tested reflected in vivo paediatric administration practices: (i.) direct administration of formulation; (ii.) formulation co-administered with vehicles (formula, milk or applesauce). Drug dissolution was significantly affected by co-administration of the formulation with vehicles compared with after direct administration of the formulation. Montelukast dissolution from the granules was significantly higher under fed-state simulated intestinal conditions in comparison with the fasted state and was predictive of the in vivo performance when the granules are co-administered with milk. This study supports the potential utility of the in vitro biorelevant dissolution approach proposed to predict in vivo formulation performance after co-administration with vehicles, in the paediatric population.

Novel High-Drug-Loaded Amorphous Dispersion Tablets of Posaconazole; In Vivo and In Vitro Assessment

Amorphous solid dispersions (ASDs) can increase the bioavailability of drugs with poor aqueous solubility. However, concentration-sustaining dispersion polymers (CSPs) incorporated in ASDs can result in low drug loading and, therefore, a large dosage-form size or multiple units to meet dose requirements, potentially decreasing patient compliance. To address this challenge, a high-loaded dosage-form (HLDF) architecture for ASDs was developed, in which a drug is first spray-dried with a high glass-transition temperature (T_g) dispersion polymer to facilitate high drug loading while maintaining physical stability. The ASD is then granulated with a CSP designed to extend supersaturation in solution. The HLDF differs from traditional ASD architectures in which the dispersion polymer inside the ASD acts as the CSP. By strategically combining two different polymers, one "inside" and one "outside" the ASD, solubilization performance, physical stability, and overall drug loading are maximized. This study demonstrates in vivo performance of the HLDF architecture using posaconazole as a model drug. Two sizes of HLDF tablets were tested in beagle dogs, along with traditional ASD architecture (benchmark) tablets, ASD tablets without a CSP, and a commercial crystalline oral suspension (Noxafil OS). HLDF tablets performed equivalently to the benchmark tablets, the smaller HLDF tablet being 40% smaller (by mass) than the benchmark tablet. The HLDF tablets doubled the blood plasma AUC relative to Noxafil OS. In line with the in vivo outcome, in vitro results in a multicompartment dissolution apparatus demonstrated similar area under the curve (AUC) values in the intestinal compartment for ASD tablets. However, the in vitro data underpredicted the relative in vivo AUC of Noxafil OS compared to the ASD tablets. This study demonstrated that the HLDF approach can increase drug loadings while achieving good performance for ASD drug products.

10th Anniversary of a Two-Stage Design in Bioequivalence. Why Has it Still Not Been Implemented?

PURPOSE

In 2010 the European Medicines Agency allowed a two-stage design in bioequivalence studies. However, in the public domain there are mainly articles describing the theoretical and statistical base for the application of the two-stage design. One of the reasons seems to be the lack of practical guidance for the Sponsors on when and how the two-stage design can be beneficial in bioequivalence studies.

METHODS

Different variants with positive and negative outcomes have been evaluated, including a pivotal study, pilot + pivotal study and two-stage study. The scientific perspective on the two-stage bioequivalence study has been confronted with the industrial one.

RESULTS

Key information needed to conduct a bioequivalence study - such as in vitro data and pharmacokinetics - have been listed and organized into a decision scheme. Advantages and disadvantages of the two-stage design have been summarized.

CONCLUSION

The use of the two-stage design in bioequivalence studies seems to be a beneficial alternative to the 2 × 2 crossover study. Basic information on the properties of the active substance and the characteristics of the drug form are needed to make an initial decision to carry out the two-stage study.

Engineering of Long-Term Stable Transparent Nanoemulsion Using High-Gravity Rotating Packed Bed for Oral Drug Delivery

Background

Oil-in-water drug nanoemulsion forms drug delivery systems with high oral bioavailability. The conventional fabrication methods of nanoemulsion are low energy emulsification methods and high energy emulsification methods. However, both two methods are not ideal for industrial production. The problem of low energy emulsification methods is the high dosage of surfactant and co-surfactant which has potential biosecurity issues. What is more, high energy emulsification methods have some disadvantages, like the destruction of drug components, the price of equipment and the difficulties of industrial production. Hence, there have been a few commercial drug nanoemulsions so far.

Methods

In this work, we reported a novel method for the fabrication of stable and transparent drug nanoemulsion which contains hydrophilic drug rosuvastatin (ROS) calcium or hydrophobic drug silybinin (SYN) by using high-gravity rotating packed bed (RPB). The drug nanoemulsion was systematically characterized by droplet size, size distribution, stability and in vitro drug release as well as Caco-2 cells permeability.

Results

Compared with the self-emulsification method (SE), high-gravity technology could reduce 75% amount of mixed surfactants. The as-prepared nanoemulsion exhibited a very narrow droplet size distribution with a size of 13.53 ± 0.53 nm and a polydispersity index of 0.073 ± 0.018. Meanwhile, the drug nanoemulsion was physicochemically stable at 25°C and 4°C for one-year storage. Furthermore, both ROS and SYN nanoemulsion displayed higher cell permeability and in vitro dissolution than that of commercial formulations.

Conclusion

These results demonstrate that RPB can be a potential device to facilitate the industrial production of drug nanoemulsion.

Self-Microemulsifying Drug Delivery System of Phillygenin: Formulation Development, Characterization and Pharmacokinetic Evaluation

Phillygenin, as an active ingredient of Forsythia suspensa, possesses a wide range of biological and pharmacological activity. However, its development and application are restricted due to its poor bioavailability and low solubility. Our work aimed to develop a self-microemulsifying drug delivery system to improve the oral bioavailability of phillygenin. The composition of the self-microemulsifying drug delivery system was preliminary screened by the pseudo-ternary phase diagram. Subsequently, the central composite design method was employed to optimize the prescription of the self-microemulsifying drug delivery system loaded with phillygenin. The prepared self-microemulsifying drug delivery system of phillygenin was characterized in terms of morphology, droplet size distribution, polydispersity index and stability. Then, the in vitro dissolution and the oral bioavailability were analyzed. The optimized self-microemulsifying drug delivery system of phillygenin consisted of 27.8% Labrafil M1944CS, 33.6% Cremophor EL, 38.6% polyethylene glycol 400 (PEG-400) and 10.2 mg/g phillygenin loading. The prepared self-microemulsifying drug delivery system of phillygenin exhibited spherical and uniform droplets with small size (40.11 ± 0.74 nm) and satisfactory stability. The in vitro dissolution experiment indicated that the cumulative dissolution rate of the self-microemulsifying drug delivery system of phillygenin was significantly better than that of free phillygenin. Furthermore, after oral administration in rats, the bioavailability of phillygenin was significantly enhanced by the self-microemulsifying drug delivery system. The relative bioavailability of the self-microemulsifying drug delivery system of phillygenin was 588.7% compared to the phillygenin suspension. These findings suggest that the self-microemulsifying drug delivery system of phillygenin can be a promising oral drug delivery system to improve the absorption of phillygenin.

Risk-Based Approach to Lot Release

In this work, a novel risk-based methodology for lot release is proposed. Its objective is to assess the risk that a lot declared to have passed truly meets product specifications. The methodology consists of 3 parts: adaptive sample size determination, estimation of the probability that the product was within specifications, and the lot-release decision. The methodology provides a probabilistic statement about the true quality of the batch. Having a probability estimate is the essential condition of risk-based decision-making. We demonstrate the proposed methodology on experimental data generated from 17 immediate-release solid oral drug products from a number of different manufacturers with 5 to 10 lots per manufacturer.

[Effect of HPMCAS/curcumin amorphous solid dispersion in enhancing dissolution and chemical stability of curcumin]

To enhance in vitro dissolution of Cur by preparing Cur solid dispersions. The ability of HPMCAS-HF,HPMCAS-MF,HPMCAS-LF and PVPK30 to maintain supersaturated solution was investigated by supersaturation test. Amorphous solid dispersions were prepared by the solvent-evaporation method. The prepared samples were characterized using infrared spectroscopy( IR) and differential scanning calorimetry( DSC),and in vitro dissolution was investigated. DSC and IR results showed that in 1 ∶3 and 1 ∶9 solid dispersions,Cur was amorphously dispersed in the carrier,and the interaction existed between drug and carrier. The supersaturation test showed that the order of the ability of polymer to inhibit crystallization of Cur was MF>HF>LF>K30. The dissolution results showed that Cur-K30 amorphous solid dispersion had the highest drug release rate; Cur-K30 and Cur-LF amorphous solid dispersions had a quicker but not stable dissolution rate,and the drug concentration decrease after 4 h; Cur-MF and Cur-HF solid dispersions had a low dissolution,which however increased steadily,attributing to the strong ability of the polymers to inhibit the crystallization of Cur. HPMCAS could inhibit the degradation of Cur better than K30,especially MF and HF. The amorphous solid dispersions of cur significantly enhanced the dissolution of Cur and improved the chemical stability of Cur. This study can provide a basis for the rational selection of the polymer used for Cur solid dispersion.

Defining the process parameters affecting the fabrication of rosuvastatin calcium nanoparticles by planetary ball mill

Purpose

Rosuvastatin calcium (ROSCa) nanoparticles were fabricated by planetary ball mill to enhance ROSCa dissolution rate and bioavailability.

Methods

Milling time factors (milling cycle time and number as well as pause time) were explored. The effect of different milling ball size, speed, and solid-to-solvent ratio were also studied using Box-Behnken factorial design. The fabricated nanoparticles were evaluated in term of physicochemical properties and long-term stability.

Results

The obtained data revealed that the integrated formulation and process factors should be monitored to obtain desirable nanoparticle attributes in terms of particle size, zeta potential, dissolution rate, and bioavailability. The optimized ROSCa nanoparticles prepared by milling technique showed a significant enhancement in the dissolution rate by 1.3-fold and the plasma concentration increased by 2-fold (P<0.05). Moreover, stability study showed that the optimized formula of ROSCa nanoparticles exhibits higher stability in long-term stability conditions at 30°C with humidity of 60%.

Conclusion

Formulation of ROSCa as nanoparticles using milling technique showed a significant enhancement in both dissolution rate and plasma concentration as well as stability compared with untreated drug.

Mass Transport Analysis of Bicarbonate Buffer: Effect of the CO2-H2CO3 Hydration-Dehydration Kinetics in the Fluid Boundary Layer and the Apparent Effective p Ka Controlling Dissolution of Acids and Bases

The main buffering system influencing ionizable drug dissolution in the human intestinal fluid is bicarbonate-based; however, it is rarely used in routine pharmaceutical practice due to the volatility of dissolved CO₂. The typical pharmaceutical buffers used fail to capture the unique aspects of the hydration-dehydration kinetics of the bicarbonate-CO₂ system. In particular, CO₂ is involved in a reversible interconversion with carbonic acid (H₂CO₃), which is the actual conjugate acid of the system, as follows CO₂ + H₂O ⇌ H₂CO₃. In contrast to ionization reactions, this interconversion does not equilibrate very rapidly compared to the diffusional processes through a typical fluid diffusion boundary layer at a solid-liquid interface. In this report, a mathematical mass transport analysis was developed for ionizable drug dissolution in bicarbonate using the rules of conservation of mass and electric charge in addition to accounting for the diffusional times and reaction rate constants of the CO₂-H₂CO₃ interconversion. This model, which includes both the hydration reaction rate and dehydration reaction rate, we called the "reversible non-equilibrium" (RNE) model. The predictions made by this RNE approach for ionizable drug dissolution rates were compared to the experimental data generated by an intrinsic dissolution method for three ionizable drugs, indomethacin, ibuprofen, and haloperidol. The results demonstrate the superiority of predictions for the RNE approach compared to the predictions of a model assuming equilibrium between CO₂ and H₂CO₃, as well as models ignoring reactions. The analysis also shows that bicarbonate buffer can be viewed as having an effective p K_a in the boundary layer that is different from that in bulk and is hydrodynamics-dependent.

A Comparative Study of the Use of Mesoporous Carbon and Mesoporous Silica as Drug Carriers for Oral Delivery of the Water-Insoluble Drug Carvedilol

Mesoporous carriers have been extensively applied to improve the dissolution velocity and bioavailability of insoluble drugs. The goal of this work was to compare the drug-loading efficiency (LE) and drug-dissolution properties of mesoporous silica nanoparticles (MSN) and mesoporous carbon nanoparticles (MCN) as drug vectors oral delivery of water-insoluble drugs. For this purpose, MSN and MCN with similar particle size, surface area, and mesoporous diameter were prepared to precisely evaluate the effects of different textures on the drug-loading and dissolution behavior of insoluble drugs. Carvedilol (CAR), a Bio-pharmaceutic Classification System (BCS) class II drug, was loaded in the MSN and MCN by the solvent adsorption method and solvent evaporation method with different carrier–drug ratios. The carboxylated MCN (MCN–COOH) had a higher LE for CAR than MSN for both the two loading methods due to the strong adsorption effect and π–π stacking force with CAR. In vitro drug dissolution study showed that both MSN and MCN-COOH could improve the dissolution rate of CAR compared with the micronized CAR. In comparison to MSN, MCN-COOH displayed a slightly slower dissolution profile, which may be ascribed to the strong interaction between MCN-COOH and CAR. Observation of cell cytotoxicity and gastrointestinal mucosa irritation demonstrated the good biocompatibility of both MSN and MCN–COOH. The present study encourages further research of different carriers to determine their potential application in oral administration.

Evaluation of Self-Nanoemulsifying Drug Delivery Systems (SNEDDS) for Poorly Water-Soluble Talinolol: Preparation, in vitro and in vivo Assessment

Objective

The aim of this study was to investigate the in vitro and in vivo performance of self-nanoemulsifying drug delivery systems (SNEDDSs) of talinolol (TAL), a poorly water-soluble drug.

Methods

Self-nanoemulsifying drug delivery systems of TAL were prepared using various oils, non-ionic surfactants and/or water-soluble co-solvents and assessed visually/by droplet size measurement. Equilibrium solubility of TAL in the anhydrous and diluted SNEDDS was conducted to achieve the maximum drug loading. The in vitro dissolution experiments and human red blood cells (RBCs) toxicity test, ex vivo gut permeation studies, and bioavailability of SNEDDS in rats were studied to compare the representative formulations with marketed product Cordanum^® 50 mg and raw drug.

Results

The results from the characterization and solubility studies showed that SNEDDS formulations were stable with lower droplet sizes and higher TAL solubility. From the dissolution studies, it was found that the developed SNEDDS provided significantly higher rate of TAL release (>97% in 2.0 h) compared to raw TAL and marketed product Cordanum^®. The RBC lysis test suggested negligible toxicity of the formulation to the cells. The ex vivo permeability assessment and in vivo pharmacokinetics study of a selected SNEDDS formulation (F6) showed about four-fold increase in permeability and 1.58-fold enhanced oral bioavailability of TAL in comparison to pure drug, respectively.

Conclusion

Talinolol loaded SNEDDS formulations could be a potential oral pharmaceutical product with high drug-loading capacity, improved drug dissolution, increased gut permeation, reduced/no human RBC toxicity, and enhanced oral bioavailability.

In Vitro Drug Dissolution/Permeation Testing of Nanocarriers for Skin Application: a Comprehensive Review

This review highlights in vitro drug dissolution/permeation methods available for topical and transdermal nanocarriers that have been designed to modulate the propensity of drug release, drug penetration into skin, and permeation into systemic circulation. Presently, a few of USFDA-approved in vitro dissolution/permeation methods are available for skin product testing with no specific application to nanocarriers. Researchers are largely utilizing the in-house dissolution/permeation testing methods of nanocarriers. These drug release and permeation methods are pending to be standardized. Their biorelevance with reference to in vivo plasma concentration-time profiles requires further exploration to enable translation of in vitro data for in vivo or clinical performance prediction.

[Study on preparation of volatile oil from Acorus tatarinowii self-nanoemulsion dropping pills and its protective effect on acute myocardial ischemia injury]

In this study, solid dispersion technology was used to develop volatile oil from Acorus tatarinowii self-nanoemulsion dropping pills(VOA-SNEDDS-DP) and its protective effect on acute myocardial ischemia injury was evaluated. Taking exterior quality, weight variation and the resolving time as comprehendsive evaluation indexes, the preparation process and formulation of the dropping pills were optimized by orthogonal design, and the dissolution rate in vitro of the optimized VOA-SNEDDS-DP was investigated. The rat model of acute myocardial ischemia was induced by intraperitoneal injection of isoproterenol hydrochloride and the serum levels of superoxide dismutase(SOD), malondialdehyde(MDA), creatine kinase(CK) and pathological changes of myocardial tissue were determined to evaluate therapeutic effect of the dropping pills on acute myocardial ischemia. The results showed that the optimal formulation and preparation process of VOA-SNEDDS-DP were as follows: PEG6000-PEG8000 was 1∶1, proportion of VOA-SNEDDS and matrix was l∶2.5, the temperature of drug fluids was 75 ℃, drop rate was 35 drops/min, drop distance was 5 cm, the condensing agent temperature was 2-10 ℃. The content of β-asarone in the dropping pills was 42.46 mg·g~(-1). The accumulated dissolution rate of the dropping pills reached 93.85% in 10 min. The results of pharmacodynamic experiments showed that VOA-SNEDDS-DP could significantly increase the SOD content(P<0.05), reduce the levels of MDA and CK(P<0.05) in serum, and effectively improve the pathological morphology of myocardial tissue. These results revealed that the preparation of VOA-SNEDDS-DP by solid dispersion technology was stable and feasible, and VOA-SNEDDS-DP had protective effect on acute myocardial ischemia injury.

Exploring Bioequivalence of Dexketoprofen Trometamol Drug Products with the Gastrointestinal Simulator (GIS) and Precipitation Pathways Analyses

The present work aimed to explain the differences in oral performance in fasted humans who were categorized into groups based on the three different drug product formulations of dexketoprofen trometamol (DKT) salt—Using a combination of in vitro techniques and pharmacokinetic analysis. The non-bioequivalence (non-BE) tablet group achieved higher plasma C_max and area under the curve (AUC) than the reference and BE tablets groups, with only one difference in tablet composition, which was the presence of calcium monohydrogen phosphate, an alkalinizing excipient, in the tablet core of the non-BE formulation. Concentration profiles determined using a gastrointestinal simulator (GIS) apparatus designed with 0.01 N hydrochloric acid and 34 mM sodium chloride as the gastric medium and fasted state simulated intestinal fluids (FaSSIF-v1) as the intestinal medium showed a faster rate and a higher extent of dissolution of the non-BE product compared to the BE and reference products. These in vitro profiles mirrored the fraction doses absorbed in vivo obtained from deconvoluted plasma concentration–time profiles. However, when sodium chloride was not included in the gastric medium and phosphate buffer without bile salts and phospholipids were used as the intestinal medium, the three products exhibited nearly identical concentration profiles. Microscopic examination of DKT salt dissolution in the gastric medium containing sodium chloride identified that when calcium phosphate was present, the DKT dissolved without conversion to the less soluble free acid, which was consistent with the higher drug exposure of the non-BE formulation. In the absence of calcium phosphate, however, dexketoprofen trometamol salt dissolution began with a nano-phase formation that grew to a liquid–liquid phase separation (LLPS) and formed the less soluble free acid crystals. This phenomenon was dependent on the salt/excipient concentrations and the presence of free acid crystals in the salt phase. This work demonstrated the importance of excipients and purity of salt phase on the evolution and rate of salt disproportionation pathways. Moreover, the presented data clearly showed the usefulness of the GIS apparatus as a discriminating tool that could highlight the differences in formulation behavior when utilizing physiologically-relevant media and experimental conditions in combination with microscopy imaging.

First-Principles and Empirical Approaches to Predicting In Vitro Dissolution for Pharmaceutical Formulation and Process Development and for Product Release Testing

This manuscript represents the perspective of the Dissolution Working Group of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) and of two focus groups of the American Association of Pharmaceutical Scientists (AAPS): Process Analytical Technology (PAT) and In Vitro Release and Dissolution Testing (IVRDT). The intent of this manuscript is to show recent progress in the field of in vitro predictive dissolution modeling and to provide recommended general approaches to developing in vitro predictive dissolution models for both early- and late-stage formulation/process development and batch release. Different modeling approaches should be used at different stages of drug development based on product and process understanding available at those stages. Two industry case studies of current approaches used for modeling tablet dissolution are presented. These include examples of predictive model use for product development within the space explored during formulation and process optimization, as well as of dissolution models as surrogate tests in a regulatory filing. A review of an industry example of developing a dissolution model for real-time release testing (RTRt) and of academic case studies of enabling dissolution RTRt by near-infrared spectroscopy (NIRS) is also provided. These demonstrate multiple approaches for developing data-rich empirical models in the context of science- and risk-based process development to predict in vitro dissolution. Recommendations of modeling best practices are made, focused primarily on immediate-release (IR) oral delivery products for new drug applications. A general roadmap is presented for implementation of dissolution modeling for enhanced product understanding, robust control strategy, batch release testing, and flexibility toward post-approval changes.

Preparation and in vitro-in vivo characterization of trans-resveratrol nanosuspensions

Nanosuspensions technique is an important tool to enhance the saturation solubility and dissolution velocity of poorly soluble drugs. Trans-resveratrol (t-Res) with extensive pharmacological effects was severely restricted by poor solubility and short biological half-life. In this study, anti-solvent precipitation was employed to development trans-resveratrol nanosuspensions (t-Res NS) with PVPK30 as stabilizer. The physicochemical properties, in vitro release and in vivo pharmacokinetics of t-Res NS were investigated. The mean particle size, zeta potential, encapsulation efficiency and drug loading of t-Res NS prepared by the optimal prescription were 96.9 nm, -20.4mV, 78% and 28.1%, respectively. The morphology of t-Res nanoparticles was spherical indicated by SEM with amorphous phase verified by XRD and DSC. The t-Res NS present a good physical stability as well as enhanced chemical stability. Compared to crude drug, the in vitro dissolution rate of t-Res NS was increased with fitting Higuchi equation (Q=0.3215t1/2+0.0070). The in vivo pharmacokinetic test in rats showed that the AUC0∼t of t-Res NS (559.4 μg/mL·min) was about 3.6-fold higher than that of t-Res solution. Meanwhile, the MRT of t-Res nanosuspensions was longer than that of t-Res solution. These results suggested that NS may be a potentially nanocarrier for clinical delivery of t-Res.

A Simple Approach for Comparing the In Vitro Dissolution Profiles of Highly Variable Drug Products: a Proposal

When in vitro dissolution profile variability prohibits the use of the F2 metric, there currently is no satisfactory alternative available. Published reports evaluating alternative approaches such as Multivariate Statistical Distance and use of a bootstrap F2 identify sources of bias that can limit the utility of these alternatives. Within veterinary medicine, an additional complication is the potential magnitude of interlot variability associated with dosage forms containing "natural" ingredients. In situations when both interlot and intralot variability need to be factored in the test and reference profile comparison, we designed a method that integrates such concepts as F2, USP S1 and S2 criteria and statistical tolerance limits. Unlike F2, this alternative approach integrates a statistical confidence into the determination through the use of tolerance limits about the reference product profile. Moreover, while differences in product variability, along with differences in mean profiles, will influence the comparability assessment, this method does not impose the need to confirm homogeneity of variances: there is not direct statistical comparison of test versus reference dissolution data. For more typical situations when interlot variability is not a concern, the F2 component can be omitted from the profile comparison. Lastly, by being a model-independent approach, we avoid the potential for introducing error into the comparability determination due either to model misspecification or problems associated with a lack of collinearity. This manuscript details this alternative approach and the results of performance characterization efforts to illustrate its behavior under a range of potential situations.

Development of paracetamol-caffeine co-crystals to improve compressional, formulation and in vivo performance

Paracetamol, a frequently used antipyretic and analgesic drug, has poor compression moldability owing to its low plasticity. In this study, new co-crystals of paracetamol (PCM) with caffeine (as a co-former) were prepared and delineated. Co-crystals exhibited improved compaction and mechanical behavior. A screening study was performed by utilizing a number of methods namely dry grinding, liquid assisted grinding (LAG), solvent evaporation (SE), and anti-solvent addition using various weight ratios of starting materials. LAG and SE were found successful in the screening study. Powders at 1:1 and 2:1 weight ratio of PCM/CAF by LAG and SE, respectively, resulted in the formation of co-crystals. Samples were characterized by PXRD, DSC, and ATR-FTIR techniques. Compressional properties of PCM and developed co-crystals were analyzed by in-die heckle model. Mean yield pressure (Py), an inverse measure of plasticity, obtained from the heckle plots decreased significantly (p < .05) for co-crystals than pure drug. Intrinsic dissolution profile of co-crystals showed up to 2.84-fold faster dissolution than PCM and physical mixtures in phosphate buffer pH 6.8 at 37 °C. In addition, co-crystals formulated into tablets by direct compression method showed better mechanical properties like hardness and tensile strength. In vitro dissolution studies on tablets also showed enhanced dissolution profiles (∼90-97%) in comparison to the tablets of PCM prepared by direct compression (∼55%) and wet granulation (∼85%) methods. In a single dose sheep model study, co-crystals showed up to twofold increase in AUC and C_max. A significant (p < .05) decrease in clearance as compared to pure drug was also recorded. In conclusion, new co-crystals of PCM were successfully prepared with improved tabletability in vitro and in vivo profile. Enhancement in AUC and C_max of PCM by co-crystallization might suggest the dose reduction and avoidance of side effects.