Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Sitagliptin Phosphate Monohydrate

Biowaiver monographs for immediate-release solid oral dosage forms: Voriconazole

According to the ICH M9 Guideline, the triazole antifungal voriconazole is a Biopharmaceutics Classification System (BCS) class II drug, being highly soluble at the highest dose strength but not at the highest single dose. Although the ICH M9 allows for consideration of BCS-based biowaivers in such cases, voriconazole does not meet the additional requirement of dose proportional pharmacokinetics (PK) over the therapeutic dose range. By contrast, if the classification were based on the FDA solubility criteria that were in place prior to ICH M9 (based on the highest dose strength), voriconazole would belong to BCS class I and thus qualify for the BCS-based biowaiver. Since the highest oral dose strength of voriconazole dissolves very rapidly under all BCS conditions, and comparative in vitro dissolution of different tablet formulations aligns with the demonstration of BE in clinical studies, it seems that the ICH Guideline may be unnecessarily restrictive in the case of voriconazole. Therefore, this review discusses potential revisions of eligibility criteria and the extension of biowaiver approvals to encompass a wider range of appropriate drugs. Specifically, a classification system that is more relevant to in vivo conditions, the refined Developability Classification System (rDCS), coupled with biorelevant dissolution testing, may be more applicable to compounds like voriconazole.

Biowaiver monographs for immediate-release solid oral dosage forms: Lemborexant

Lemborexant is a dual orexin receptor antagonist assigned to class II of the Biopharmaceutics Classification System (BCS). Thus, the ICH M9 Guideline excludes immediate-release (IR) solid oral dosage forms containing lemborexant from BCS-based biowaivers, irrespective of their in vitro dissolution behavior. By contrast, classification of lemborexant according to the refined Developability Classification System (rDCS) falls into class I, indicating few biopharmaceutics risks. Customized rDCS investigations identify dissolution as the main risk factor, in line with clinical data in humans which suggest that the absorption of lemborexant is limited neither by solubility nor by permeability. Instead, any risks lie in dissolution. Analysis by the rDCS coupled with biorelevant dissolution testing thus provides a way forward for manufacturers to mitigate the risks associated with changes in formulation or introduction of a generic version prior to running clinical bioequivalence (BE) studies. As a way forward regarding biowaivers for lemborexant and similar cases, where justifying BE based on the current BCS-based approach is not possible, a four-step pathway towards establishing BE virtually could be adopted as follows: (i) rDCS analysis to identify critical bioavailability attributes, (ii) comparative (biorelevant) dissolution testing, (iii) Physiologically Based Biopharmaceutics Modeling (PBBM), and (iv) virtual BE assessment.

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.

Development of Clinically Optimized Sitagliptin and Dapagliflozin Complex Tablets: Pre-Formulation, Formulation, and Human Bioequivalence Studies

The purpose of this study is to derive an optimal drug release formulation with human clinical bioequivalence in developing a sitagliptin phosphate monohydrate-dapagliflozin propanediol hydrate fixed-dose combination (FDC) tablet as a treatment for type 2 diabetes mellitus. As a treatment for type 2 diabetes mellitus, the combined prescription of dipeptidyl peptidase-4 (DPP-4) inhibitors and sodium-glucose cotransporter-2 (SGLT-2) inhibitors is common. Therefore, this study simplified the number of individual drugs taken and improved drug compliance by developing FDC tablets containing sitagliptin phosphate monohydrate as a DPP-4 inhibitor and dapagliflozin propanediol hydrate as an SGLT-2 inhibitor. To derive the optimal dosage form, we prepared single-layer tablets, double-layer tablets, and dry-coated tablets and evaluated the drug control release ability, tableting manufacturability, quality, and stability. Single-layer tablets caused problems with stability and drug dissolution patterns. When the dissolution test was performed on the dry-coated tablets, a corning effect occurred, and the core tablet did not completely disintegrate. However, in the quality evaluation of the double-layer tablets, the hardness was 12-14 kilopond, the friability was 0.2%, and the disintegration was within 3 min. In addition, the stability test revealed that the double-layer tablet was stable for 9 months under room temperature storage conditions and 6 months under accelerated storage conditions. In the drug release test, only the FDC double-layer tablet showed the optimal drug release pattern that satisfied each drug release rate. In addition, the FDC double-layer tablet showed a high dissolution rate of over 80% in the form of immediate-release tablets within 30 min in a pH 6.8 dissolution solution. In the human clinical trial, we co-administered a single dose of a sitagliptin phosphate monohydrate-dapagliflozin propanediol hydrate FDC double-layered tablet and the reference drug (Forxiga^®, Januvia^®) in healthy adult volunteers. This study showed clinically equivalent results in the stability and pharmacodynamic characteristics between the two groups.

Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Levocetirizine Dihydrochloride

Levocetirizine, a histamine H1-receptor antagonist, is prescribed to treat uncomplicated skin rashes associated with chronic idiopathic urticaria as well as the symptoms of both seasonal and continual allergic rhinitis. In this monograph, the practicality of using Biopharmaceutics Classification System (BCS) based methodologies as a substitute for pharmacokinetic studies in human volunteers to appraise the bioequivalence of immediate-release (IR) oral, solid dosage forms containing levocetirizine dihydrochloride was investigated, using data from the literature and in-house testing. Levocetirizine's solubility and permeability properties, as well as its dissolution from commercial products, its therapeutic uses, therapeutic index, pharmacokinetics and pharmacodynamic traits, were reviewed in accordance with the BCS, along with any reports in the literature about failure to meet bioequivalence (BE) requirements, bioavailability issues, drug-excipient interactions as well as other relevant information. The data presented in this monograph unequivocally point to classification of levocetirizine in BCS Class 1. For products that are somewhat supra-equivalent or somewhat sub-equivalent, clinical risks are expected to be insignificant in light of levocetirizine's wide therapeutic index and unlikelihood of severe adverse effects. After careful consideration of all the information available, it was concluded that the BCS-based biowaiver can be implemented for products which contain levocetirizine dihydrochloride, provided (a) the test product comprises excipients that are typically found in IR oral, solid drug products that have been approved by a country belonging to or associated with ICH and are used in quantities that are typical for such products, (b) data supporting the BCS-based biowaiver are gathered using ICH-recommended methods, and (c) all in vitro dissolution requirements specified in the ICH guidance are met by both the test and comparator products (in this case, the comparator is the innovator product).

Exploiting synergistic effects of brittle and plastic excipients in directly compressible formulations of Sitagliptin phosphate and Sitagliptin hydrochloride

Direct compression (DC) is the simplest and most economical way to produce pharmaceutical tablets. Ideally, it consists of only two steps: dry blending of a drug substance(s) with excipients followed by compressing the powder mixture into tablets. In this study, immediate-release film-coated tablets containing either Sitagliptin phosphate or Sitagliptin hydrochloride were developed using DC technique.After establishing the optimum ratio of ductile and brittle excipients, five formulations were compressed into tablets using a rotary press and finally film coated. Both powders and tablets were examined by standard pharmacopoeial methods. It has been shown that the simultaneous use of excipients with different physical properties, i.e., ductile microcrystalline cellulose and brittle anhydrous dibasic calcium phosphate, produces a synergistic effect, allowing preparation of Sitagliptin DC tablets with good mechanical strength (tensile strength over 2 N/mm²), rapid disintegration (shorter than 2 min), and fast release of the drug substance (85% of the drug is dissolved within 15 minutes). It was found that the type of calcium phosphate excipient used had a large effect on the properties of the sitagliptin tablets. All formulations developed showed good chemical stability, even when stored under stress conditions (50 °C/80% RH).

Evaluation of Excipient Risk in BCS Class I and III Biowaivers

The objective of this review article is to summarize literature data pertinent to potential excipient effects on intestinal drug permeability and transit. Despite the use of excipients in drug products for decades, considerable research efforts have been directed towards evaluating their potential effects on drug bioavailability. Potential excipient concerns stem from drug formulation changes (e.g., scale-up and post-approval changes, development of a new generic product). Regulatory agencies have established in vivo bioequivalence standards and, as a result, may waive the in vivo requirement, known as a biowaiver, for some oral products. Biowaiver acceptance criteria are based on the in vitro characterization of the drug substance and drug product using the Biopharmaceutics Classification System (BCS). Various regulatory guidance documents have been issued regarding BCS-based biowaivers, such that the current FDA guidance is more restrictive than prior guidance, specifically about excipient risk. In particular, sugar alcohols have been identified as potential absorption-modifying excipients. These biowaivers and excipient risks are discussed here.