Short-Term Outcomes of a High-Volume, Low-Concentration Bolus Starting Dose Technique With Ziconotide: A Case Series.

BACKGROUND AND OBJECTIVES: There have been numerous recommendations for a starting dose of intrathecal ziconotide. The therapy remains underutilized partially due to reports of inefficacy and/or intolerance. This study describes short-term outcomes of a high-volume, low-concentration bolus (HVLC-B) ziconotide starting dose technique for patients with chronic spine pain. Intrathecal pumps are available with a Patient Therapy Manager (PTM), or patient-controlled intrathecal bolus device. Commonly published recommendations for a bolus dose has been 10% of the daily dose. This article describes an inversion of the traditional 10% rule-of-thumb. This article describes using the basal rate at a lowest programmable dose and utilizing the bolus for the majority of the medication delivery. Such an inversion may be considered a high volume bolus. The lowest commercially available concentration of ziconotide from the manufacturer is 25 mcg/mL. Pope and Deer (Neuromodulation, 18, 414-420 [2015]) described use of a dilution down to 5 mcg/mL. For purposes of this article, such dilutions to one-fifth of the commercially available solution are considered sufficiently dilute to qualify for the term "low concentration." Furthermore, the patients in this analysis received dilutions down to one-fiftieth of the lowest commercially available solution. MATERIALS AND METHODS: A case series of patients with chronic spine pain with or without radicular pain received a starting dose intrathecal ziconotide regimen based on a specific HVLC-B technique. Efficacy, tolerability, and pump settings are reported and analyzed. RESULTS: In total, 17 patients were identified who started ziconotide with the specified HVLC-B starting regimen. One of the 17 patients reported side effects that led to discontinuation of the therapy, although the side effect was not typical of ziconotide but rather likely attributable to other medications the patient was taking. Fifteen of the 17 reported improved pain control with intrathecal ziconotide. Sixteen of the 17 patients remained on intrathecal ziconotide throughout the 4.7-month average follow-up period. One patient who failed to obtain pain relief chose to remain on the therapy because of reported resolution of lower limb numbness. CONCLUSIONS: The HVLC-B starting regimen was effective and well tolerated in this short-term study of patients with chronic spine pain. More studies are needed to better elucidate long-term outcomes in larger patient populations.

ICH M9 Guideline in Development on Biopharmaceutics Classification System-Based Biowaivers: An Industrial Perspective from the IQ Consortium.

In October 2016, the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) ICH began efforts to provide recommendations to harmonize guidances for biopharmaceutics classification system (BCS)-based biowaivers. Topics to be addressed included consideration of the dose used to classify solubility, tests, and criteria for establishing highly permeable, dissolution conditions, the influence of excipients, and aspects of product strength. The International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) is a technically focused organization of pharmaceutical and biotechnology companies with a mission of advancing science and technology to augment the capability of member companies to develop transformational solutions that benefit patients, regulators, and the broader R&D community. Its members have substantial expertise in all scientific domains associated with BCS-based waivers and drug product quality, as well as considerable experience in the application of BCS-based biowaivers. The ICH process recognizes that harmonization is achieved through the development of guidelines via a process of scientific consensus with regulatory and industry experts working side-by-side. Thus, to facilitate these efforts and to encourage open and transparent discussion of other perspectives that may exist, IQ offers their perspective on these and related topics.

The EED protein-protein interaction inhibitor A-395 inactivates the PRC2 complex.

Polycomb repressive complex 2 (PRC2) is a regulator of epigenetic states required for development and homeostasis. PRC2 trimethylates histone H3 at lysine 27 (H3K27me3), which leads to gene silencing, and is dysregulated in many cancers. The embryonic ectoderm development (EED) protein is an essential subunit of PRC2 that has both a scaffolding function and an H3K27me3-binding function. Here we report the identification of A-395, a potent antagonist of the H3K27me3 binding functions of EED. Structural studies demonstrate that A-395 binds to EED in the H3K27me3-binding pocket, thereby preventing allosteric activation of the catalytic activity of PRC2. Phenotypic effects observed in vitro and in vivo are similar to those of known PRC2 enzymatic inhibitors; however, A-395 retains potent activity against cell lines resistant to the catalytic inhibitors. A-395 represents a first-in-class antagonist of PRC2 protein-protein interactions (PPI) for use as a chemical probe to investigate the roles of EED-containing protein complexes.

Striking the Optimal Solubility-Permeability Balance in Oral Formulation Development for Lipophilic Drugs: Maximizing Carbamazepine Blood Levels.

The purpose of this research was to investigate the performance of cosolvent based solubility-enabling formulations in oral delivery of lipophilic drugs, accounting for the gastrointestinal tract (GIT) luminal solubilization processes, the solubility-permeability interplay, and the overall in vivo systemic absorption. The poorly soluble antiepileptic agent carbamazepine was formulated in three cosolvent-based formulations: 20%, 60%, and 100% PEG-400, and the apparent solubility and rat permeability of the drug in these formulations were evaluated. The performance of the formulations in the dynamic GIT environment was assessed utilizing the biorelevant pH-dilution method. Then, the overall in vivo drug exposure was investigated following oral administration to rats. The three formulations showed dramatic solubility and permeability differences; the 100% PEG-400 provided the highest solubility enhancement and the 20% the poorest, while the exact opposite was evident from the permeability point of view. The dissolution results indicated that the 20% PEG-400 formulation crashes quickly following oral administration, but both the 60% and the 100% PEG-400 formulations allowed full solubilization of the dose throughout the entire GIT-like journey. The best in vivo performing formulation was the 60% PEG-400 (Fsys > 90%), followed by the 100% PEG-400 (Fsys = 76%), and the 20% PEG-400 formulation (Fsys ≈ 60%). In conclusion, this work demonstrates the in vivo solubility-permeability trade-off in oral delivery of lipophilic drugs; when a solubility-enabling formulation is developed, minimal threshold solubility should be targeted, that is just enough to allow solubilization of the drug dose throughout the GIT, while excess solubilizer should be avoided.

Toward Successful Cyclodextrin Based Solubility-Enabling Formulations for Oral Delivery of Lipophilic Drugs: Solubility-Permeability Trade-Off, Biorelevant Dissolution, and the Unstirred Water Layer.

The purpose of this work was to investigate key factors dictating the success/failure of cyclodextrin-based solubility-enabling formulations for oral delivery of low-solubility drugs. We have studied the solubility, the permeability, and the solubility-permeability interplay, of the highly lipophilic drug danazol, formulated with different levels (8.5, 10, 20, and 30%) of the commonly used hydroxypropyl-ß-cyclodextrin (HPßCD), accounting for the biorelevant solubilization of the drug along the gastrointestinal tract (GIT), the unstirred water layer (UWL) adjacent to the GI membrane, and the overall absorption. HPßCD significantly increased danazol solubility, and decreased the drugs' permeability, in a concentration-dependent manner. These Peff results were in good correlation (R2 = 0.977) to literature rat AUC data of the same formulations. Unlike vehicle without HPßCD, formulations containing 8.5% HPßCD and above were shown to successfully dissolve the drug dose during the entire biorelevant dissolution experiment. We conclude that CD-based solubility-enabling formulations should contain the minimal amount of CD sufficient to dissolve the drug dose throughout the GIT, and not more than that; excess CD does not provide solubility gain but causes further permeability loss, and the overall absorption is then impaired. Moreover, a significant UWL effect was revealed in danazol intestinal permeability, and accounting for this effect allowed an excellent prediction of the solubility-permeability trade-off vs % HPßCD. Overall, this work assessed the contribution of each individual step of the absorption cascade to the success/failure of HPßCD-based formulation, allowing a more mechanistic development process of better solubility-enabling formulations.

THE EVALUATION OF PEPTIDE/HISTIDINE TRANSPORTER 1 (PHT1) FUNCTION: UPTAKE KINETICS UTILIZING A COS-7 STABLY TRANSFECTED CELL LINE.

There have been relatively few studies focused on the proton-dependent oligopeptide transporter (POT) superfamily member, Peptide/Histidine Transporter 1 (PHT1), with respect to its contribution to the ADME of peptides and peptide-based drugs. These studies were conducted to determine hPHT1-mediated, H+-dependent uptake kinetics of histidine, carnosine, Gly-Sar and valacyclovir in stably transfected hPHT1-COS-7 cells comparative to kinetics determined in an empty vector (Mock) stably transfected cell line. The results suggest that Gly-Sar appears to be a substrate for PHT1 based on efflux from the stably transfected hPHT1 COS-7 cells. Histidine and Gly-Sar concentration- and time-dependent studies suggest mixed-uptake kinetics. These studies suggest that stably transfected hPHT1-COS-7 cells exhibit different uptake kinetics than those observed in our previous studies and illustrate the requirement for experiments to delineate the physiological role of hPHT1.

A method to evaluate body length of live aquatic vertebrates using digital images.

Traditional methods to measure body lengths of aquatic vertebrates rely on anesthetics, and extended handling times. These procedures can increase stress, potentially affecting the animal's welfare after its release. We developed a simple procedure using digital images to estimate body lengths of coastal cutthroat trout (Oncorhynchus clarkii clarkii) and larval coastal giant salamander (Dicamptodon tenebrosus). Images were postprocessed using ImageJ2. We measured more than 900 individuals of these two species from 200 pool habitats along 9.6 river kilometers. The percent error (mean ± SE) of our approach compared to the use of a traditional graded measuring board was relatively small for all length metrics of the two species. Total length of trout was -2.2% ± 1.0. Snout-vent length and total length of larval salamanders was 3.5% ± 3.3 and -0.6% ± 1.7, respectively. We cross-validated our results by two independent observers that followed our protocol to measure the same animals and found no significant differences (p > .7) in body size distributions for all length metrics of the two species. Our procedure provides reliable information of body size reducing stress and handling time in the field. The method is transferable across taxa and the inclusion of multiple animals per image increases sampling efficiency with stored images that can be reviewed multiple times. This practical tool can improve data collection of animal size over large sampling efforts and broad spatiotemporal contexts.

ABC and SLC transporter expression and proton oligopeptide transporter (POT) mediated permeation across the human blood--brain barrier cell line, hCMEC/D3 [corrected].

Initial studies indicate that the newly developed hCMEC/D3 cell line may prove to be a useful model for studying the physiology of the human blood-brain barrier (BBB) endothelium. The purpose of this study was to assess the mRNA expression of several ABC and SLC transporters, with an emphasis on the proton-coupled oligopeptide transporter superfamily (POT) transporters in this immortalized BBB cell model. The transport kinetics of POT-substrates was also evaluated. The hCMEC/D3 cell line was maintained in a modified EGM-2 medium in collagenated culture flasks and passaged every 3-4 days at approximately 85%-95% confluence. Messenger RNA (mRNA) expression of a variety of ABC and SLC transporters was evaluated using qRT-PCR arrays, while additional qRT-PCR primers were designed to assess the expression of POT members. The transport kinetics of mannitol and urea were utilized to quantitatively estimate the intercellular pore radius, while POT substrate transport was also determined to assess the suitability of the cell model from a drug screening perspective. Optimization of the cell line was attempted by culturing with on laminin and fibronectin enhanced collagen and in the presence of excess Ca(2+). hCMEC/D3 cells express both hPHT1 and hPHT2, while little to no expression of either hPepT1 or hPepT2 was observed. The relative expression of other ABC and SLC transporters is discussed. While POT substrate transport does suggest suitability for BBB drug permeation screening, the relative intercellular pore radius was estimated at 19 A, significantly larger than that approximated in vivo. Culturing with extracellular matrix proteins did not alter mannitol permeability. These studies characterized this relevant human hCMEC/D3 BBB cell line with respect to both the relative mRNA expression of various ABC and SLC transporters and its potential utility as an in vitro screening tool for brain permeation. Additional studies are required to adequately determine the potential to establish an in vivo correlation.

Twelve-month analgesia and rescue, by cooled radiofrequency ablation treatment of osteoarthritic knee pain: results from a prospective, multicenter, randomized, cross-over trial.

BACKGROUND AND OBJECTIVES: As a follow-up to the 6-month report,12 this study investigated the analgesic effect of cooled radiofrequency ablation (CRFA) in patients with knee osteoarthritis (OA) 12 months postintervention and its ability to provide pain relief in patients who experienced unsatisfactory effects of intra-articular steroid injection (IAS). METHODS: Seventy-eight per cent (52/67) of patients originally treated with CRFA were evaluated at 12 months, while at 6 months post-IAS, 82% (58/71) of those patients crossed over to CRFA and assessed 6 months later. RESULTS: At 12 months, 65% of the original CRFA group had pain reduction ≥50%, and the mean overall drop was 4.3 points (p<0.0001) on the numeric rating scale. Seventy-five per cent reported 'improved' effects. The cross-over group demonstrated improvements in pain and functional capacity (p<0.0001). No unanticipated adverse events occurred. CONCLUSIONS: This study demonstrates that analgesia following CRFA for OA knee pain could last for at least 12 months and could rescue patients who continue to experience intolerable discomfort following IAS. CLINICAL TRIAL REGISTRATION: The ClinicalTrials.gov registration number for this study is NCT02343003.

Prospective, Multicenter, Randomized, Crossover Clinical Trial Comparing the Safety and Effectiveness of Cooled Radiofrequency Ablation With Corticosteroid Injection in the Management of Knee Pain From Osteoarthritis.

BACKGROUND AND OBJECTIVES: Osteoarthritis (OA) of the knee affects the aging population and has an associated influence on the health care system. Rigorous studies evaluating radiofrequency ablation for OA-related knee pain are lacking. This study compared long-term clinical safety and effectiveness of cooled radiofrequency ablation (CRFA) with intra-articular steroid (IAS) injection in managing OA-related knee pain. METHODS: This is a prospective, multicenter, randomized trial with 151 subjects with chronic (≥6 months) knee pain that was unresponsive to conservative modalities. Knee pain (Numeric Rating Scale [NRS]), Oxford Knee Score, overall treatment effect (Global Perceived Effect), analgesic drug use, and adverse events were compared between CRFA and IAS cohorts at 1, 3, and 6 months after intervention. RESULTS: There were no differences in demographics between study groups. At 6 months, the CRFA group had more favorable outcomes in NRS: pain reduction 50% or greater: 74.1% versus 16.2%, P < 0.0001 (25.9% and 83.8% of these study cohorts, respectively, were nonresponders). Mean NRS score reduction was 4.9 ± 2.4 versus 1.3 ± 2.2, P < 0.0001; mean Oxford Knee Score was 35.7 ± 8.8 vs 22.4 ± 8.5, P < 0.0001; mean improved Global Perceived Effect was 91.4% vs 23.9%, P < 0.0001; and mean change in nonopioid medication use was CRFA > IAS (P = 0.02). There were no procedure-related serious adverse events. CONCLUSIONS: This study demonstrates that CRFA is an effective long-term therapeutic option for managing pain and improving physical function and quality of life for patients with painful knee OA when compared with IAS injection. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT02343003).

Mechanistic Physiologically Based Pharmacokinetic Modeling of the Dissolution and Food Effect of a Biopharmaceutics Classification System IV Compound-The Venetoclax Story.

Venetoclax, a selective B-cell lymphoma-2 inhibitor, is a biopharmaceutics classification system class IV compound. The aim of this study was to develop a physiologically based pharmacokinetic (PBPK) model to mechanistically describe absorption and disposition of an amorphous solid dispersion formulation of venetoclax in humans. A mechanistic PBPK model was developed incorporating measured amorphous solubility, dissolution, metabolism, and plasma protein binding. A middle-out approach was used to define permeability. Model predictions of oral venetoclax pharmacokinetics were verified against clinical studies of fed and fasted healthy volunteers, and clinical drug interaction studies with strong CYP3A inhibitor (ketoconazole) and inducer (rifampicin). Model verification demonstrated accurate prediction of the observed food effect following a low-fat diet. Ratios of predicted versus observed Cmax and area under the curve of venetoclax were within 0.8- to 1.25-fold of observed ratios for strong CYP3A inhibitor and inducer interactions, indicating that the venetoclax elimination pathway was correctly specified. The verified venetoclax PBPK model is one of the first examples mechanistically capturing absorption, food effect, and exposure of an amorphous solid dispersion formulated compound. This model allows evaluation of untested drug-drug interactions, especially those primarily occurring in the intestine, and paves the way for future modeling of biopharmaceutics classification system IV compounds.

Advantageous Solubility-Permeability Interplay When Using Amorphous Solid Dispersion (ASD) Formulation for the BCS Class IV P-gp Substrate Rifaximin: Simultaneous Increase of Both the Solubility and the Permeability.

Rifaximin is a BCS class IV (low-solubility, low-permeability) drug and also a P-gp substrate. The aims of this work were to assess the efficiency of different rifaximin amorphous solid dispersion (ASDs) formulations in achieving and maintaining supersaturation and to investigate the consequent solubility-permeability interplay. Spray-dried rifaximin ASDs were prepared with different hydrophilic polymers and their ability to achieve and maintain supersaturation was assessed. Then, rifaximin's apparent intestinal permeability was investigated as a function of increasing supersaturation both in vitro using the parallel artificial membrane permeability assay (PAMPA) and in vivo using the single-pass rat intestinal perfusion (SPIP) model. The efficiency of the different ASDs to achieve and maintain supersaturation of rifaximin was found to be highly polymer dependent, and the copovidone/HPC-SL formulation was found to be superior to the other two, allowing supersaturation of 200× that of the crystalline solubility for 20 h. In vitro, rifaximin flux was increased and the apparent permeability was constant as a function of increasing supersaturation level. In vivo, on the other hand, absorption rate coefficient (k a) was first constant as a function of increasing supersaturation, but at 250×, the crystalline solubility k a was doubled, similar to the k a in the presence of the strong P-gp inhibitor GF120918. In conclusion, a new and favorable nature of solubility-permeability interplay was revealed in this work: delivering high supersaturation level of the BCS class IV drug rifaximin via ASD, thereby saturating the drugs' P-gp-mediated efflux transport, led to the favorable unique win-win situation, where both the solubility and the permeability increased simultaneously.

Concomitant solubility-permeability increase: Vitamin E TPGS vs. amorphous solid dispersion as oral delivery systems for etoposide.

Vitamin E TPGS (TPGS) has both surfactant and P-glycoprotein (P-gp) inhibitory effects. While surfactants were previously found to cause solubility-permeability tradeoff, TPGS P-gp inhibitory effects may change this unfavorable interplay. The purpose of this research was to investigate the solubility-permeability interplay when using TPGS vs. amorphous solid dispersions (ASD) as oral drug delivery systems for the anticancer, P-gp substrate, lipophilic drug etoposide. The concentration-dependent effects of TPGS (0-100mg/mL) vs. ASD on the solubility of etoposide, as well as the in-vitro (PAMPA) vs. in-vivo (intestinal rat perfusion) permeability of the drug were studied, and the resulting solubility-permeability interplay was analyzed. TPGS above CMC (0.3mg/mL) increased etoposide solubility linearly, and ASD allowed significant supersaturation. Etoposide in-vitro PAMPA permeability decreased markedly with increasing TPGS levels, similarly to the solubility-permeability tradeoff previously defined for surfactants. In contrast, the presence of TPGS significantly increased etoposide in-vivo rat permeability, attributable to P-gp inhibition, similarly to the effect of the potent P-gp inhibitor GF120918 (10µg/mL). High supersaturation achieved via ASD increased the drug's in-vivo permeability to the level obtained by TPGS or GF120918, supporting P-gp saturation. In conclusion, unique pattern of solubility-permeability interplay was found, involving concomitant increase of both the solubility and the permeability, as opposed to the previously reported tradeoff for solubilization methods and the unchanged permeability for supersaturation; P-gp inhibition/saturation by TPGS or by supersaturation allows simultaneous increase of both solubility and permeability, representing a significant advantage of such drug delivery approaches when suitable.

The solubility-permeability interplay and oral drug formulation design: Two heads are better than one.

Poor aqueous solubility is a major challenge in today's biopharmaceutics. While solubility-enabling formulations can significantly increase the apparent solubility of the drug, the concomitant effect on the drug's apparent permeability has been largely overlooked. The mathematical equation to describe the membrane permeability of a drug comprises the membrane/aqueous partition coefficient, which in turn is dependent on the drug's apparent solubility in the GI milieu, suggesting that the solubility and the permeability are closely related, exhibit a certain interplay between them, and treating the one irrespectively of the other may be insufficient. In this article, an overview of this solubility-permeability interplay is provided, and the available data is analyzed in the context of the effort to maximize the overall drug exposure. Overall, depending on the type of solubility-permeability interplay, the permeability may decrease, remain unchanged, and even increase, in a way that may critically affect the formulation capability to improve the overall absorption. Therefore, an intelligent design of solubility-enabling formulation needs to consider both the solubility afforded by the formulation and the permeability in the new luminal environment resulting from the formulation.

Hydrotropic Solubilization of Lipophilic Drugs for Oral Delivery: The Effects of Urea and Nicotinamide on Carbamazepine Solubility-Permeability Interplay.

Hydrotropy refers to increasing the water solubility of otherwise poorly soluble compound by the presence of small organic molecules. While it can certainly increase the apparent solubility of a lipophilic drug, the effect of hydrotropy on the drugs' permeation through the intestinal membrane has not been studied. The purpose of this work was to investigate the solubility-permeability interplay when using hydrotropic drug solubilization. The concentration-dependent effects of the commonly used hydrotropes urea and nicotinamide, on the solubility and the permeability of the lipophilic antiepileptic drug carbamazepine were studied. Then, the solubility-permeability interplay was mathematically modeled, and was compared to the experimental data. Both hydrotropes allowed significant concentration-dependent carbamazepine solubility increase (up to ∼30-fold). A concomitant permeability decrease was evident both in vitro and in vivo (∼17-fold for nicotinamide and ∼9-fold for urea), revealing a solubility-permeability tradeoff when using hydrotropic drug solubilization. A relatively simplified simulation approach based on proportional opposite correlation between the solubility increase and the permeability decrease at a given hydrotrope concentration allowed excellent prediction of the overall solubility-permeability tradeoff. In conclusion, when using hydrotropic drug solubilization it is prudent to not focus solely on solubility, but to account for the permeability as well; achieving optimal solubility-permeability balance may promote the overall goal of the formulation to maximize oral drug exposure.

Head-To-Head Comparison of Different Solubility-Enabling Formulations of Etoposide and Their Consequent Solubility-Permeability Interplay.

The purpose of this study was to conduct a head-to-head comparison of different solubility-enabling formulations, and their consequent solubility-permeability interplay. The low-solubility anticancer drug etoposide was formulated in several strengths of four solubility-enabling formulations: hydroxypropyl-ß-cyclodextrin, the cosolvent polyethylene glycol 400 (PEG-400), the surfactant sodium lauryl sulfate, and an amorphous solid dispersion formulation. The ability of these formulations to increase the solubility of etoposide was investigated, followed by permeability studies using the parallel artificial membrane permeability assay (PAMPA) and examination of the consequent solubility-permeability interplay. All formulations significantly increased etoposide's apparent solubility. The cyclodextrin-, surfactant-, and cosolvent-based formulations resulted in a concomitant decreased permeability that could be modeled directly from the proportional increase in the apparent solubility. On the contrary, etoposide permeability remained constant when using the ASD formulation, irrespective of the increased apparent solubility provided by the formulation. In conclusion, supersaturation resulting from the amorphous form overcomes the solubility-permeability tradeoff associated with other formulation techniques. Accounting for the solubility-permeability interplay may allow to develop better solubility-enabling formulations, thereby maximizing the overall absorption of lipophilic orally administered drugs.