Lipophilic Salts and Lipid-Based Formulations for Bridging the Food Effect Gap of Venetoclax

Enhancing oral bioavailability of dasatinib via supersaturable SNEDDS: Investigation of precipitation inhibition and IVIVC through in-vitro lipolysis-permeation model

Dasatinib (DASA), a potent second-generation multitarget kinase inhibitor marketed as Sprycel® (Tablet), is limited by poor oral bioavailability (14-24 %) and dose-related gastrointestinal side effects. A supersaturable self-nanoemulsifying drug delivery system (su-SNEDDS) designed to enhance DASA's solubility, sustain supersaturation, and improve oral bioavailability. The su-SNEDDS formulation comprises DASA, an oil, surfactant, co-surfactant, and polyvinylpyrrolidone (PVP) K30 as a precipitation inhibitor (PI). This innovative system demonstrated exceptional stability in gastrointestinal fluids and robustness against dilution, maintaining significantly elevated drug concentrations in the aqueous milieu. su-SNEDDS achieved ∼ 13.5-fold and 2-fold higher aqueous drug concentrations than DASA suspension and SNEDDS without PI, respectively, after 60 min of digestion. This improvement is attributed to the inhibition of crystal growth by PVP K30. In-vitro lipolysis-permeation and Caco-2 cell assays revealed significantly enhanced drug permeation with su-SNEDDS compared to DASA suspension and SNEDDS without PI. In-vivo pharmacokinetic studies further demonstrated ∼ 1.9-fold and 2.7-fold higher AUC compared to SNEDDS without PI and drug suspension, respectively. A linear correlation (R2 = 0.9042) was established between the AUC data obtained from in-vitro vs in-vivo study. These findings underscore the potential of su-SNEDDS to significantly enhance DASA's solubility, permeation and oral bioavailability, presenting a substantial advancement in pharmaceutical drug delivery systems. Moreover, in-vitro lipolysis-permeation could be promising tool to predict the in-vivo fate of the oral SNEDDS formulations.

Development of polymer-encapsulated microparticles of a lipophilic API-IL and its lipid based formulations for enhanced solubilisation

Active Pharmaceutical Ingredient-Ionic liquids (API-ILs) have the potential to improve the bioavailability of BCS Class IV Drugs. However, the problematic physical handling properties of room temperature API-ILs have impaired clinical and commercial exploitation to date. Lipid-based formulations (LBFs) are used to improve the absorption of drugs with limited bioavailability. Nonetheless, LBFs face limitations such as low drug loading capacity and sub-par physical stability. A platform for transforming API-ILs into solid forms at high loadings via spray encapsulation with polymers has been developed and previously demonstrated for hydrophilic API-ILs. The current work demonstrates that this platform technology can be applied to a lipophilic API-IL of the BCS Class IV API, chlorpromazine, and to multi-component solutions comprising API-IL and a LBF. Furthermore, solidification of a type IIIB, liquid LBF was achieved via spray encapsulation with cellulose- and methacrylate- based polymers for the first time. The spray-encapsulated formulations had excellent physical handling properties, and successfully eluted the API-IL in aqueous media. The chlorpromazine release profiles from the API-IL, the API-IL containing LBF, and the solidified formulations, were evaluated in vitro using phosphate buffer (pH 6.8) and fasted state simulated intestinal fluid (FaSSIF). Spray-encapsulated formulations exhibited improved release profiles compared to the liquid formulations. Overall, these findings indicate that phase-separated, polymeric, solid formulations of liquid API forms represent a promising platform technology for developing oral solid dosage forms of poorly bioavailable drugs.

Hydrophobic deep eutectic solvent (HDES) as oil phase in lipid-based drug formulations

There is increasing pharmaceutical interest in deep eutectic solvents not only as a green alternative to organic solvents in drug manufacturing, but also as liquid formulation for drug delivery. The present work introduces a hydrophobic deep eutectic solvent (HDES) to the field of lipid-based formulations (LBF). Phase behavior of a mixture with 2:1 M ratio of decanoic- to dodecanoic acid was studied experimentally and described by thermodynamic modelling. Venetoclax was selected as a hydrophobic model drug and studied by atomistic molecular dynamics simulations of the mixtures. As a result, valuable molecular insights were gained into the interaction networks between the different components. Moreover, experimentally the HDES showed greatly enhanced drug solubilization compared to conventional glyceride-based vehicles, but aqueous dispersion behavior was limited. Hence surfactants were studied for their ability to improve aqueous dispersion and addition of Tween 80 resulted in lowest droplet sizes and high in vitro drug release. In conclusion, the combination of HDES with surfactant(s) provides a novel LBF with high pharmaceutical potential. However, the components must be finely balanced to keep the integrity of the solubilizing HDES, while enabling sufficient dispersion and drug release.

A Lipophilic Salt Form to Enhance the Lipid Solubility and Certain Biopharmaceutical Properties of Lapatinib

Lapatinib (LTP) commercially available as lapatinib ditosylate (LTP-DTS) salt is the only drug approved for the treatment of HER-positive metastatic breast cancer. A low and pH-dependent solubility results in poor and variable oral bioavailability, thus driving significant interest in molecular modification and formulation strategies of the drug. Furthermore, due to very high crystallinity, LTP and LTP-DTS have low solubility in lipid excipients, making it difficult to be delivered by lipid-based carrier systems. Thus, the present work reports a new salt form of LTP with a docusate counterion to enhance the pharmaceutical properties of the drug (LTP-DOC). NMR spectra showed a downfield shift of the methylene singlet proton from 3.83 and 4.41 ppm, indicating a lowering of electron density on the adjacent nitrogen atom and confirming the formation of amine-sulfonyl salt through the specified basic nitrogen center located adjacent to the furan ring. PXRD diffractograms of LTP-DOC indicated a reduced crystallinity of the prepared salt. The dissolution, equilibrium solubility, lipid excipient solubility, partitioning coefficient, distribution coefficient, tabletability, and in vitro cytotoxicity of the lipophilic salt of LTP were investigated. The equilibrium solubility data showed that LTP-DOC possesses a pH-independent solubility profile in the pH range of 3.5 to 7.4 with a 3.14 times higher permeability coefficient than commercial ditosylate salt. Furthermore, the prepared LTP-DOC salts showed twice higher log P than the free base and 8 times higher than LTP-DTS. The prepared LTP-DOC was found to have 4- to 9-fold higher solubility in lipid excipients like Capmul MCM C8 and Maisine CC compared to the ditosylate salt. The LTP-DOC salt was tabletable and showed approximately 1.2 times lower dissolution than commercial ditosylate salt, indicating extended-release behavior. A cytotoxicity study of LTP-DOC salt showed an approximately 2.5 times lower IC50 value than the LTP-free base and 1.7 times lower than commercial ditosylate salt with an approximately 3 times higher selectivity index. The investigations strongly indicate a high translational potential of the prepared salt form in maintaining solubility-lipophilicity interplay, enhancing the drug's bioavailability, and developing lipidic formulations.

Rationalizing Counterion Selection for the Development of Lipophilic Salts: A Case Study with Venetoclax

The use of lipid-based formulations (LBFs) can be hindered by low dose loading due to solubility limitations of candidate drugs in lipid vehicles. Formation of lipophilic salts through pairing these drugs with a lipophilic counterion has been demonstrated as a potential means to enhance dose loading in LBFs. This study investigated the screening of appropriate counterions to form lipophilic salts of the BCS class IV drug venetoclax. The physical properties, lipid solubility, and in vitro performance of the salts were analyzed. This study illustrated the versatility of alkyl sulfates and sulfonates as suitable counterions in lipophilic salt synthesis with up to ∼9-fold higher solubility in medium- and long-chain LBFs when compared to that of the free base form of venetoclax. All salts formulated as LBFs displayed superior in vitro performance when compared to the free base form of the drug due to the higher initial drug loadings in LBFs and increased affinity for colloidal species. Further, in vitro studies confirmed that venetoclax lipophilic salt forms using alkyl chain counterions demonstrated comparable in vitro performance to venetoclax docusate, thus reducing the potential for laxative effects related to docusate administration. High levels of the initial dose loading of venetoclax lipophilic salts were retained in a molecularly dispersed state during dispersion and digestion of the formulation, while also demonstrating increased levels of saturation in biorelevant media. The findings of this study suggest that alkyl chain sulfates and sulfonates can act as a suitable alternative counterion to docusate, facilitating the selection of counterions that can unlock the potential to formulate venetoclax as an LBF.

Enabling superior drug loading in lipid-based formulations with lipophilic salts for a brick dust molecule: Exploration of lipophilic counterions and in vitro-in vivo evaluation

Lipid-based formulations (LbFs) are an extensively used approach for oral delivery of poorly soluble drug compounds in the form of lipid suspension and lipid solution. However, the high target dose and inadequate lipid solubility limit the potential of brick dust molecules to be formulated as LbFs. Thus, the complexation of such molecules with a lipophilic counterion can be a plausible approach to improve the solubility in lipid-based solutions via reducing drug crystallinity and polar surface area. The study aimed to enhance drug loading in lipid solution for Nilotinib (Nil) through complexation or salt formation with different lipophilic counterions. We synthesized different lipophilic salts/ complexes via metathesis reactions and confirmed their formation by 1H NMR and FTIR. Docusate-based lipophilic salt showed improved solubility in medium-chain triglycerides (∼7 to 7.5-fold) and long-chain triglycerides (∼30 to 35-fold) based lipids compared to unformulated crystalline Nil. The increased lipid solubility could be attributed to the reduction in drug crystallinity which was further confirmed by the PXRD and DSC. Prototype LbFs were prepared to evaluate drug loading and their physicochemical characteristics. The findings suggested that structural features of counterion including chain length and lipophilicity affect the drug loading in LbF. In addition, physical stability testing of formulations was performed, inferring that aliphatic sulfate-based LbFs were stable with no sign of drug precipitation or salt disproportionation. An in vitro lipolysis-permeation study revealed that the primary driver of absorptive flux is the solubilization of the drug and reduced amount of lipid. Further, the in vivo characterization was conducted to measure the influence of increased drug load on oral bioavailability. Overall, the results revealed enhanced absorption of lipophilic salt-based LbF over unformulated crystalline Nil and conventional LbF (drug load equivalent to equilibrium solubility) which supports the idea that lipophilic salt-based LbF enhances drug loading, and supersaturation-mediated drug solubilization, unlocking the full potential of LbF.

Quality by design approach-based fabrication and evaluation of self-nanoemulsifying drug delivery system for improved delivery of venetoclax

Breast cancer is reported as one of the most prevalent non-cutaneous malignancies in women. Venetoclax (VEN) is an approved BCl-2 inhibitor for the treatment of chronic myeloid leukemia with very limited oral bioavailability and exhibits an enormous impact on breast cancer. In the current investigation, venetoclax-loaded self-nanoemulsifying drug delivery systems (VEN-SNEDDS) were designed and fabricated to improve the aqueous solubility, permeability, and anticancer efficacy of VEN. Various surface-active parameters of the reconstituted SNEDDS were determined to scrutinize the performance of the selected surfactant mixture. Central composite design (CCD) was used to optimize the VEN-SNEDDS. The globule size of reconstituted VEN-SNEDDS was 71.3 ± 2.8 nm with a polydispersity index of 0.113 ± 0.01. VEN-SNEDDS displayed approximately 3-4 fold, 6-7 fold, and 5-6 fold reduced IC50 as compared to free VEN in MDA-MB-231, MCF-7, and T47 D cells, respectively. VEN-SNEDDS showed greater cellular uptake, apoptosis, reactive oxygen species generation, and higher BAX/BCL2 ratio with decreased caspase 3 and 8 and BCL-2 levels in the MDA-MB-231 cells compared to pure VEN. VEN-SNEDDS exhibited approximately fivefold enhancement in Cmax and an improved oral bioavailability compared to VEN suspension in in vivo pharmacokinetic studies.

Twin Screw Melt Granulation: A Single Step Approach for Developing Self-Emulsifying Drug Delivery System for Lipophilic Drugs

The current research aims to improve the solubility of the poorly soluble drug, i.e., ibuprofen, by developing self-emulsifying drug delivery systems (SEDDS) utilizing a twin screw melt granulation (TSMG) approach. Gelucire® 44/14, Gelucire® 48/16, and Transcutol® HP were screened as suitable excipients for developing the SEDDS formulations. Initially, liquid SEDDS (L-SEDDS) were developed with oil concentrations between 20-50% w/w and surfactant to co-surfactant ratios of 2:1, 4:1, 6:1. The stable formulations of L-SEDDS were transformed into solid SEDDS (S-SEDDS) using a suitable adsorbent carrier and compressed into tablets (T-SEDDS). The S-SEDDS has improved flow, drug release profiles, and permeability compared to pure drugs. The existence of the drug in an amorphous state was confirmed by differential scanning calorimetry (DSC) and powder X-ray diffraction analysis (PXRD). The formulations with 20% w/w and 30% w/w of oil concentration and a 4:1 ratio of surfactant to co-surfactant have resulted in a stable homogeneous emulsion with a globule size of 14.67 ± 0.23 nm and 18.54 ± 0.55 nm. The compressed tablets were found stable after six months of storage at accelerated and long-term conditions. This shows the suitability of the TSMG approach as a single-step continuous manufacturing process for developing S-SEDDS formulations.

Bio-enabling strategies to mitigate the pharmaceutical food effect: a mini review

The concomitant administration of oral drugs with food can result in significant changes in bioavailability, leading to variable pharmacokinetics and considerable clinical implications, such as over- or under-dosing. Consequently, there is increasing demand for bio-enabling formulation strategies to reduce variability in exposure between the fasted and fed state and/or mitigate the pharmaceutical food effect. The current review critically evaluates technologies that have been implemented to overcome the positive food effects of pharmaceutical drugs, including, lipid-based formulations, nanosized drug preparations, cyclodextrins, amorphisation and solid dispersions, prodrugs and salts. Additionally, improved insight into preclinical models for predicting the food effect is provided. Despite the wealth of research, this review demonstrates that application of optimal formulation strategies to mitigate the positive food effects and the evaluation in preclinical models is not a universal approach, and improved standardisation of models to predict the food effects would be desirable. Ultimately, the successful reformulation of specific drugs to eliminate the food effect provides a panoply of advantages for patients with regard to clinical efficacy and compliance.