Biowaiver Monographs for Immediate-Release Solid Oral Dosage Forms: Folic Acid

Coupling Drug Dissolution with BCS

PURPOSE

The purpose of this study is to develop a Temporal Biopharmaceutic Classification System (T-BCS), linking Finite Dissolution Time (F.D.T.) and Mean Dissolution Time (M.D.T.) for Class I/III drugs and Mean Dissolution Time for saturation (M.D.T.s.) for Class II/IV drugs.

METHODS

These parameters are estimated graphically or by fitting dissolution models to experimental data and coupled with the dose-to-solubility ratio (q) for each drug normalized in terms of the actual volume of dissolution medium (900 mL).

RESULTS

Class I/III drugs consistently exhibited q values less than 1, aligning with expectations based on their solubility, while some Class II/IV drugs presented a deviation from anticipated q values, with observations of q < 1. This irregularity was rendered to the dissolution volume of 250 mL used for biopharmaceutical classification purposes instead of 900 mL applied as well as the dual classification of some sparingly soluble drugs. Biowaivers were also analyzed in terms of M.D.T., F.D.T. estimates and the regulatory dissolution time limits for rapidly and very-rapidly dissolved drugs.

CONCLUSIONS

The T-BCS is useful for establishing correlations and assessing the magnitude of M.D.T., F.D.T., or M.D.T.s. for inter- and intra-class comparisons of different drugs and provide relationships between these parameters across all the models that were utilized.

Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Isavuconazonium Sulfate

A Biopharmaceutics Classification System (BCS)-based biowaiver monograph is presented for isavuconazonium sulfate. A BCS-based biowaiver is a regulatory option to substitute appropriate in vitro data for in vivo bioequivalence studies. Isavuconazonium sulfate is the prodrug of isavuconazole, a broad-spectrum azole antifungal indicated for invasive fungal infections. While the prodrug can be classified as a BCS Class III drug with high solubility but low permeability, the parent drug can be classified as a BCS Class II drug with low solubility but high permeability. Interestingly, the in vivo behavior of both is additive and leads isavuconazonium sulfate to act like a BCS class I drug substance after oral administration. In this work, experimental solubility and dissolution data were evaluated and compared with available literature data to investigate whether it is feasible to approve immediate release solid oral dosage forms containing isavuconazonium sulfate according to official guidance from the FDA, EMA and/or ICH. The risks associated with waiving a prodrug according to the BCS-based biowaiver guidelines are reviewed and discussed, noting that current regulations are quite restrictive on this point. Further, results show high solubility but instability of isavuconazonium sulfate in aqueous media. Although experiments on the dissolution of the capsule contents confirmed 'very rapid' dissolution of the active pharmaceutical ingredient (API) isavuconazonium sulfate, its release from the commercial marketed capsule formulation Cresemba is limited by the choice of capsule shell material, providing an additional impediment to approval of generic versions via the BCS-Biowaiver approach.

A novel method for automated crystal visualization and quantification in murine folic acid-induced acute kidney injury

Folic acid (FA)-induced acute kidney injury (FA-AKI) is an increasingly prevalent rodent disease model involving the injection of a high dose of FA that culminates in renal FA crystal deposition and injury. However, the literature characterizing the FA-AKI model is sparse and dated in part due to the absence of a well-described methodology for the visualization and quantification of renal FA crystals. Using widely available materials and tools, we developed a straightforward and crystal-preserving histological protocol that can be coupled with automated imaging for renal FA crystal visualization and generated an automated macro for downstream crystal content quantification. The applicability of the method was demonstrated by characterizing the model in male and female C57BL6/JRj mice after 3 and 30 h of FA treatment. Kidneys from both sexes and timepoints showed a bimodal distribution of FA crystal deposition in the cortical and medullary regions while, compared with males, females exhibited higher renal FA crystal content at the 30-h timepoint accompanied by greater kidney weight and higher plasma urea. Despite comparable plasma phosphate concentrations, FA-AKI resulted in a substantially more elevated plasma intact fibroblast growth factor 23 (FGF23) in females, reflected by a similar pattern in osseous Fgf23 mRNA expression. Therefore, the presented method constitutes a valuable tool for the quantification of renal FA crystals, which can aid the mechanistic characterization of the FA-AKI model and serves as a means to control for confounding changes in FA crystallization when using the model for investigating early and prophylactic AKI therapeutic interventions.NEW & NOTEWORTHY Here, we describe a novel method for the visualization and quantification of renal folic acid (FA) crystals in the rodent FA-induced acute kidney injury (FA-AKI) model. The protocol involves a straightforward histological approach followed by fully automated imaging and quantification steps. Applicability was confirmed by showing that the FA-AKI model is sex-dependent. The method can serve as a tool to aid in characterizing FA-AKI and to control for studies investigating prophylactic therapeutic avenues using FA-AKI.

Effect of Basic Amino Acids on Folic Acid Solubility

To prevent neural tube defects and other cardiovascular diseases in newborns, folic acid (FA) is recommended in pregnant women. A daily dose of 600 µg FA consumption is widely prescribed for women during pregnancy and 400 µg for women with childbearing potential. FA is a class IV compound according to the Biopharmaceutics Classification System (BCS) due to its low permeability (1.7 × 10-6 cm/s) and low solubility (1.6 mg/L); therefore, it must be administered via a formulation that enhances its solubility. Studies reported in the literature have proved that co-amorphization and salt formation of a poorly soluble drug with amino acids (AA) can significantly increase its solubility. Although arginine has been used with FA as a supplement, there is no information on the effect of basic AA (arginine and lysine) on the physical and chemical properties of FA-AA binary formulations. The present study implemented a conductimetric titration methodology to find the effective molar ratio to maximize FA solubility. The results showed that a 1:2.5 FA:AA molar ratio maximized solubility for arginine and lysine. Binary formulations were prepared using different methods, which led to an amorphous system confirmed by the presence of a glass transition, broad FTIR bands, and the absence of an X-ray diffraction pattern. Results of FA:AA (1:2.5) solubility increased in the range of 5500-6000 times compared with pure FA. In addition to solubility enhancement, the binary systems presented morphological properties that depend on the preparation method and whose consideration could be strategic for scaling purposes.

A review of transglycosylated compounds as food additives to enhance the solubility and oral absorption of hydrophobic compounds in nutraceuticals and pharmaceuticals

Transglycosylation has been used to modify the physicochemical properties of original compounds. As a result, transglycosylated compounds can form molecular aggregates in size ranges of a few nanometers in an aqueous medium when their concentrations exceed a specific level. Incorporating these hydrophobic compounds has been observed to enhance the solubility of hydrophobic compounds into aggregate structures. Thus, this review introduces four transglycosylated compounds as food additives that can enhance the solubility and oral absorption of hydrophobic compounds. Here, transglycosylated hesperidin, transglycosylated rutin, transglycosylated naringin, and transglycosylated stevia are the focus as representative substances. Significantly, we observed that amorphous formations containing hydrophobic compounds with transglycosylated compounds improved solubility and oral absorption compared to untreated hydrophobic compounds. Moreover, combining transglycosylated compounds with hydrophilic polymers or surfactants enhanced the solubilizing effects on hydrophobic compounds. Furthermore, the enhanced solubility of hydrophobic compounds improved their oral absorption. Transglycosylated compounds also influenced nanoparticle preparation of hydrophobic compounds as a dispersant. This study demonstrated the benefits of transglycosylated compounds in developing supplements and nutraceuticals of hydrophobic compounds with poor aqueous solubility.

Folic acid and sodium folate salts: Thermal behavior and spectroscopic (IR, Raman, and solid-state 13C NMR) characterization

Folic acid (FA; vitamin B9) and its associated sodium salts, strongly relevant for many scientific and technological applications - from nutrition to pharmacology and nanomedicine, suffer from a lack of characterization combining experimental and theoretical. In this work, a spectroscopic investigation of FA and its synthesized sodium salts in the form of dianion (Na₂HFol) or trianion (Na₃Fol) was scrutinized in their solid state. The spectroscopic (infrared, Raman, and solid state ¹³C-nuclear magnetic resonance) data interpretation was supported by theoretical calculations using the Density Functional Theory (DFT). Additionally, the compounds were characterized by UV-VIS diffuse-reflectance spectroscopy, combined thermal analysis (TG/DTG-DSC) coupled to mass spectrometry, and X-ray diffractometry. The main signatures of each species were identified, as well as the influence of the protonation level on their physicochemical properties. These distinct properties for the three compounds are mainly based on signals assigned to glutamic acid (glutamate) and pterin (neutral or anionic) moieties. This work should help developing new products based on FA or its anionic forms, such as theragnostic/drug delivery systems, supramolecular structures, nanocarbons, or metal complexes.

Characterization of a hyaluronic acid and folic acid-based hydrogel for cisplatin delivery: Antineoplastic effect in human ovarian cancer cells in vitro

We successfully prepared and characterized a hyaluronic acid- and folic acid-based hydrogel for the delivery of cisplatin (GEL-CIS) with the aim to induce specific and efficient incorporation of CIS into ovarian cancer (OC) cells, improve its antineoplastic effect and avoid CIS-resistance. The slow and controlled release of the drug from the polymeric network and its swelling degree at physiologic pH suggested its suitability for CIS delivery in OC. We compared here the effects of pure CIS to that of GEL-CIS on human OC cell lines, either wild type or CIS-resistant, in basal conditions and in the presence of macrophage-derived conditioned medium, mimicking the action of tumor-associated macrophages in vivo. GEL-CIS inhibited OC cell growth and migration more efficiently than pure CIS and modulated the expression of proteins involved in the Epithelial Mesenchymal Transition, a process playing a key role in OC metastatic spread and resistance to CIS.

Gliclazide: Biopharmaceutics Characteristics to Discuss the Biowaiver of Immediate and Extended Release Tablets

The lists of essential medicines of the World Health Organization (WHO) and Brazil include gliclazide as an alternative to the oral antidiabetic drug of first choice, metformin, in the treatment of type 2 diabetes mellitus because of its pharmacokinetic profile and few side effects. Thus, it is also considered by WHO and the International Pharmaceutical Federation (FIP) as a drug candidate to biowaiver, which is the evaluation of how favorable the biopharmaceutics characteristics are in order to obtain waiver from the relative bioavailability/bioequivalence (RB/BE) studies to register new medicines. This paper presents a review about the solubility, permeability and dissolution of gliclazide. A critical analysis of the information allowed to identify gliclazide as a Biopharmaceutics Classification System (BCS) Class II drug. Therefore, new drugs in immediate release dosage forms will not be eligible for biowaiver. Regarding the extended release dosage forms, besides the limited solubility, no information on the comparative dissolution profile was found, which would be necessary to analyze a possible biowaiver for a smaller dosage. It can be concluded that the registration of new medicines containing gliclazide must undergo RB/BE studies, since there is not enough evidence to recommend the replacement and waiver of such studies for immediate and extended release formulations.

Simulation of Human Small Intestinal Digestion of Starch Using an In Vitro System Based on a Dialysis Membrane Process

This work deepens our understanding of starch digestion and the consequent absorption of hydrolytic products generated in the human small intestine. Gelatinized starch dispersions were digested with α-amylase in an in vitro intestinal digestion system (i-IDS) based on a dialysis membrane process. This study innovates with respect to the existing literature, because it considers the impact of simultaneous digestion and absorption processes occurring during the intestinal digestion of starchy foods and adopts phenomenological models that deal in a more realistic manner with the behavior found in the small intestine. Operating the i-IDS at different flow/dialysate flow ratios resulted in distinct generation and transfer curves of reducing sugars mass. This indicates that the operating conditions affected the mass transfer by diffusion and convection. However, the transfer process was also affected by membrane fouling, a dynamic phenomenon that occurred in the i-IDS. The experimental results were extrapolated to the human small intestine, where the times reached to transfer the hydrolytic products ranged between 30 and 64 min, according to the flow ratio used. We consider that the i-IDS is a versatile system that can be used for assessing and/or comparing digestion and absorption behaviors of different starch-based food matrices as found in the human small intestine, but the formation and interpretation of membrane fouling requires further studies for a better understanding at physiological level. In addition, further studies with the i-IDS are required if food matrices based on fat, proteins or more complex carbohydrates are of interest for testing. Moreover, a next improvement step of the i-IDS must include the simulation of some physiological events (e.g., electrolytes addition, enzyme activities, bile, dilution and pH) occurring in the human small intestine, in order to improve the comparison with in vivo data.

Miniaturized shake-flask HPLC method for determination of distribution coefficient of drugs used in inflammatory bowel diseases

A new method for determination of distribution coefficient of drugs azathioprine, 6-mercaptopurine and 6-thioguanine and nutrient folic acid used in the treatment of inflammatory bowel disease based on a miniaturized shake-flask and HPLC/DAD was developed. Special attention was made to the most commonly reported problems in the measurement of distribution coefficients using a shake-flask method such as mixing technique, speed and time, the temperature of experiment, type of buffer and its pH as well as n-octanol/buffer phase ratio. The concentration of compounds in the buffer is determined by HPLC directly from shake flasks or conventional 2-mL vials. The developed method was fully validated according to ICH guidelines. Furthermore, experimental data were successfully compared with lipophilicity and human intestinal absorption calculated by the use of four different theoretical approaches. The method shows potential for high-throughput measurements of a large number of compounds.

Development of Dermal Films Containing Miconazole Nitrate

This study aims to develop new antifungal dermal films based on their mechanical properties (elongation, adhesion, behaviour towards vapour moisture) and the in vitro availability of miconazole nitrate, used as a pharmaceutical active ingredient in various concentrations. The three polymeric films prepared were translucent or shiny, with the surface of 63.585 cm², 0.20⁻0.30 mm thickness, and content of miconazole nitrate of 3.931 or 15.726 mg·cm². The mechanical resistance and elongation tests demonstrated that the two films based on hydroxyethyl cellulose (HEC) polymer were more elastic than the one prepared with hydroxypropyl methylcellulose (HPMC). The vapour water absorption and vapour water loss capacity of the films revealed that the HPMC film did not dry very well in the process of preparation by the evaporation of the solvent technique, unlike the HEC films that jellified more evenly in water and had higher drying capacity at 40 °C. The in vitro availability of miconazole nitrate from dermal films was evaluated using the Franz diffusion cell method, through a synthetic membrane (Ø 25 mm × 0.45 µm) and acceptor media with pH 7.4 (phosphate buffer and sodium lauryl sulphate 0.045%), resulting a release rate of up to 70%.