A biopharmaceutical classification-based Right-First-Time formulation approach to reduce human pharmacokinetic variability and project cycle time from First-In-Human to clinical Proof-Of-Concept

Physical and dissolution characterization of cilostazol solid dispersions prepared by hot melt granulation (HMG) and thermal adhesion granulation (TAG) methods

A growing number of poorly water-soluble drug have been discovered, but the poor bioavailability is a critical problem. In this study, physical properties and dissolution profiles of cilostazol solid dispersions prepared by hydrophilic/lipophilic excipients (Kollidon(®) VA64, tocopheryl polyethylene glycol succinate (TPGS), vitamine E) with hot-melt and thermal adhesion granulation (TAG) method to adsorb Fujicalin(®) and Microcel(®) were characterized. Results demonstrate the angle of repose in formulations with Fujicalin(®) was improved than those with Microcel(®), but the difference disappeared when more TPGS or vitamin E was added. Compared the formulation made by hot-melt and TAG method, both improved flowability. The hardness decreased with the increased amount of TPGS and vitamin E. The formulations with Microcel(®) had lower hardness than those with Fujicalin(®), because Microcel(®) has weaker adsorption ability and cannot afford much TPGS and vitamin E, leading to lower hardness. Furthermore, the solubility was almost three-fold higher than that of Pletaal(®) (7.68 ± 0.20 μg/mL) in compositions containing TPGS and vitamin E made by hot-melt or TAG method, in which a controlled drug release pattern was demonstrated. There is no significant difference on dissolution profile between hot-melt and TAG method. However, the procedure of TAG is easier, indicating its potential pharmaceutical use.

Probing the effects of experimental conditions on the character of drug-polymer phase diagrams constructed using Flory-Huggins theory

PURPOSE

Amorphous drug-polymer solid dispersions have been found to result in improved drug dissolution rates when compared to their crystalline counterparts. However, when the drug exists in the amorphous form it will possess a higher Gibb's free energy than its associated crystalline state and can recrystallize. Drug-polymer phase diagrams constructed through the application of the Flory Huggins (F-H) theory contain a wealth of information regarding thermodynamic and kinetic stability of the amorphous drug-polymer system. This study was aimed to evaluate the effects of various experimental conditions on the solubility and miscibility detections of drug-polymer binary system.

METHODS

Felodipine (FD)-Polyvinylpyrrolidone (PVP) K15 (PVPK15) and FD-Polyvinylpyrrolidone/vinyl acetate (PVP/VA64) were the selected systems for this research. Physical mixtures with different drug loadings were mixed and ball milled. These samples were then processed using Differential Scanning Calorimetry (DSC) and measurements of melting point (Tend) and glass transition (Tg) were detected using heating rates of 0.5, 1.0 and 5.0°C/min.

RESULTS

The melting point depression data was then used to calculate the F-H interaction parameter (χ) and extrapolated to lower temperatures to complete the liquid-solid transition curves. The theoretical binodal and spinodal curves were also constructed which were used to identify regions within the phase diagram. The effects of polymer selection, DSC heating rate, time above parent polymer Tg and polymer molecular weight were investigated by identifying amorphous drug miscibility limits at pharmaceutically relevant temperatures.

CONCLUSION

The potential implications of these findings when applied to a non-ambient processing method such as Hot Melt Extrusion (HME) are also discussed.

Confinement effects on drugs in thermally hydrocarbonized porous silicon

Thermally hydrocarbonized porous silicon (THCPSi) microparticles were loaded with indomethacin (IMC) and griseofulvin (GSV) using three different payloads between 6.2-19.5 and 6.2-11.4 wt %, respectively. The drug loading parameters were selected to avoid crystallization of the drug molecules on the external surface of the particles that would block the pore entrances. The successfulness of the loadings was verified with TG, DSC, and XRPD measurements. The effects of the confinement of IMC and GSV into the small mesopores of THCPSi were analyzed with helium pycnometry, FTIR, and NMR spectroscopy. The results showed the density of the THCPSi loaded drugs to be ca. 10% lower than the bulk crystalline forms, while a melt quenched amorphous drugs showed a density reduction of 3-7.5%. DSC and FTIR results confirmed that the drugs reside in an amorphous form within the THCPSi pores. Similar results were obtained with NMR, which also indicated that IMC may reside as both amorphous clusters and individual molecules within the pores. The (1)H transverse relaxation times (T2) of amorphous and THCPSi loaded drugs showed IMC relaxation times of 0.28 ms for both the cases, whereas for GSV the values were 0.32 and 0.39 ms, respectively, indicating similar limited mobility in both cases. The results indicated that strong drug-carrier interactions were not necessary for stabilizing the amorphous state of the adsorbed drug. Dissolution tests using biorelevant media, fasted state simulated intestinal fluid (FaSSIF) and simulated gastric fluid (SGF), showed that THCPSi-loaded IMC and GSV were rapidly released in FaSSIF with comparable rates to the amorphous forms, whereas in SGF the THCPSi reduced the pH dependency in the dissolution of IMC.

Cholinium-based ionic liquids with pharmaceutically active anions

Ionic liquids with cholinium-based active pharmaceutical ingredients (API-ILs) were preparedviaa simple and sustainable two-step anion exchange reaction. The resulting salts have improved upon the chemical, physical and biopharmaceutical properties of the parent APIs.

Amorphous solid dispersions and nano-crystal technologies for poorly water-soluble drug delivery

Poor water-solubility is a common characteristic of drug candidates in pharmaceutical development pipelines today. Various processes have been developed to increase the solubility, dissolution rate and bioavailability of these active ingredients belonging to BCS II and IV classifications. Over the last decade, nano-crystal delivery forms and amorphous solid dispersions have become well established in commercially available products and industry literature. This article is a comparative analysis of these two methodologies primarily for orally delivered medicaments. The thermodynamic and kinetic theories relative to these technologies are presented along with marketed product evaluations and a survey of commercial relevant scientific literature.

Highly efficient miniaturized coprecipitation screening (MiCoS) for amorphous solid dispersion formulation development

Microprecipitated bulk powder (MBP) is a novel solid dispersion technology to manufacture amorphous formulations of poorly soluble compounds that cannot be processed by spray drying or melt extrusion. An efficient high-throughput screening method has been developed to aid the selection of polymer type, drug loading and antisolvent to solvent ratio for MBP formulation development. With a 96-well platform, the miniaturized coprecipitation screening (MiCoS) includes mixing of drug and polymer in dimethylacetamide, controlled precipitation to generate MBP, filtration/washing, drying and high throughput characterization. The integrated MiCoS approach has been demonstrated with a model compound, glybenclamide. Based on the solid state stability and kinetic solubility of the MBP, hydroxypropylmethylcellulose acetate succinate polymer with 40% or lower drug loading, and antisolvent (0.01 N HCl) to solvent (dimethylacetamide) ratio of 5:1 or higher were selected to make glybenclamide MBP. MiCoS can be applied to both early and late stage formulation processing. In early stage research programs, the system can be used to enable efficacy, pharmacokinetics or mini-toxicology studies for poorly water soluble molecules using minimal amount of drug substance (2-10mg). In late stage development programs, MiCoS can be used to optimize MBP formulation by expanding the experimental design space to include additional formulation variants.

Drug nanocrystals in the commercial pharmaceutical development process

Nanosizing is one of the most important drug delivery platform approaches for the commercial development of poorly soluble drug molecules. The research efforts of many industrial and academic groups have resulted in various particle size reduction techniques. From an industrial point of view, the two most advanced top-down processes used at the commercial scale are wet ball milling and high pressure homogenization. Initial issues such as abrasion, long milling times and other downstream-processing challenges have been solved. With the better understanding of the biopharmaceutical aspects of poorly water-soluble drugs, the in vivo success rate for drug nanocrystals has become more apparent. The clinical effectiveness of nanocrystals is proven by the fact that there are currently six FDA approved nanocrystal products on the market. Alternative approaches such as bottom-up processes or combination technologies have also gained considerable interest. Due to the versatility of nanosizing technology at the milligram scale up to production scale, nanosuspensions are currently used at all stages of commercial drug development, Today, all major pharmaceutical companies have realized the potential of drug nanocrystals and included this universal formulation approach into their decision trees.

Crystalline nanosuspensions as potential toxicology and clinical oral formulations for BCS II/IV compounds

Nanosuspensions, formulations based on the reduction of the active pharmaceutical ingredient (API) particle size in the sub-micron range and most typically around 100-200 nm, represent a valuable option for formulators to facilitate oral absorption of Biopharmaceutics Classification System class II and IV compounds. Their ability to increase the API dissolution rate and subsequent absorption and thus oral bioavailability has been demonstrated in preclinical and clinical settings. This review summarizes the current experience in the biopharmaceutic field with the use of nanosuspensions as oral delivery formulations. The principles behind nanosuspensions as well as the in vitro and in silico evaluation are discussed, while examples are presented highlighting both successes as well as limitations in their application as either toxicology or clinical formulations.

Electrospun nanofibers in drug delivery: recent developments and perspectives

In this review article, some key challenges in drug delivery are first introduced and methods that have been applied in attempts to solve them enumerated. Particularly intractable problems are highlighted: these include issues of solubility, targeting and drug degradation. The technique of electrospinning is subsequently introduced, and the influence of processing parameters on the fibers produced discussed. The potential of electrospun nanofibers in drug delivery is then explored, with examples given from the recent literature to illustrate how fibers can be used to overcome hurdles in drug solubility, degradation and targeting. Future perspectives and challenges are also considered.