Impact of Formulation Parameters on In Vitro Release from Long-Acting Injectable Suspensions.

The development of long-acting injectable (LAI) suspension products has increased in recent years. A better understanding of the relationship between the physicochemical properties of these products and their in vitro as well as in vivo performance is expected to further facilitate their development and regulatory review. Using Depo-SubQ Provera 104® as the reference listed drug (RLD), four qualitatively and quantitatively (Q1/Q2) equivalent LAI suspensions with different formulation properties were prepared. Two recrystallization methods (solvent evaporation and antisolvent) were utilized to obtain active pharmaceutical ingredient (API) with different properties and solid-state characterization was performed. In addition, two different sources of the major excipient were used to prepare the Q1/Q2 equivalent suspensions. Physiochemical characterization and in vitro release testing of the prepared Q1/Q2 equivalent suspension formulations and the RLD were conducted. In vitro drug release was dependent not only on the particle size, the morphology, and the crystallinity of the API but also on the residual solvent in the API. The excipient source also affected the drug release rates.

Linking In Vitro Intrinsic Dissolution Rate and Thermodynamic Solubility with Pharmacokinetic Profiles of Bedaquiline Long-Acting Aqueous Microsuspensions in Rats.

Pharmacokinetic (PK) profiles of a range of bedaquiline (BDQ) long-acting injectable (LAI) microsuspensions in rats after parenteral (i.e., intramuscular and subcutaneous) administration were correlated with the in vitro intrinsic dissolution rate (IDR) and thermodynamic solubility of BDQ in media varying in surfactant type and concentration to better understand the impact of different nonionic surfactants on the in vivo performance of BDQ LAI microsuspensions. All LAI formulations had a similar particle size distribution. The investigated surfactants were d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), poloxamer 338, and poloxamer 188. Furthermore, the relevance of medium complexity by using a biorelevant setup to perform in vitro measurements was assessed by comparing IDR and thermodynamic solubility results obtained in biorelevant media and formulation vehicle containing different surfactants in varying concentrations. In the presence of a surfactant, both media could be applied to obtain in vivo representative dissolution and solubility data because the difference between the biorelevant medium and formulation vehicle was predominantly nonsignificant. Therefore, a more simplistic medium in the presence of a surfactant was preferred to obtain in vitro measurements to predict the in vivo PK performance of LAI aqueous suspensions. The type of surfactant influenced the PK profiles of BDQ microsuspensions in rats, which could be the result of a surfactant effect on the IDR and/or thermodynamic solubility of BDQ. Overall, two surfactant groups could be differentiated: TPGS and poloxamers. Most differences between the PK profiles (i.e., maximum concentration observed, time of maximum concentration observed, and area under the curve) were observed during the first 21 days postdose, the time period during which particles in the aqueous suspension are expected to dissolve.

Mechanistic understanding of salt-induced drug encapsulation in nanosuspension via acid-base neutralization as a nanonization platform technology to enhance dissolution rate of pH-dependent poorly water-soluble drugs.

An acid-base neutralization technique has generated interest for the ability to achieve an enhanced dissolution of pH-dependent weakly basic or acidic poorly water-soluble drugs. However, the underlying nanonization mechanism, following acid-base neutralization, requires further elucidation. We hypothesized that the nanosuspensions (NSPs) via nanonization of drug particles could be attributed to the "salt-induced effect" and surfactant-driven micellization after acid-base neutralization. Rebamipide (RBM) and valsartan (VAL) were chosen as model drugs owing to poor water solubility and pH-dependent aqueous solubility. The drug NSP was rapidly obtained via salt formation (NaCl) after neutralization of the drug in basic NaOH solution and poloxamer 407 (POX 407) in acidic HCl solution. The NSP surrounded by NaCl salt was further stabilized by POX 407. The resulting NaCl salt modulated the critical micelle aggregation of POX 407, stabilizing the drug-loaded NSP in a cage of salt and micellar surfactant. In non-assisted homogenization, size analysis indicated the relationship between salt concentration and size reduction. Fourier transform infrared (FTIR) spectra revealed that the existence of hydrogen bonding between the drug and surfactant after neutralization, attributed to NSP size reduction. Changes in drug crystallinity to the nano-amorphous state were confirmed by powder X-ray diffraction (PXRD). Overall, the salt-induced drug NSP synergistically enhanced the dissolution rate, narrowing a gap between drug dissolution profiles in different pH environments.

Bevacizumab-Conjugated Quantum Dots: In Vitro Antiangiogenic Potential and Biosafety in Rat Retina.

Purpose: Disturbances that affect the inside of the eyeball tend to be highly harmful since they compromise the homeostasis of this organ. Alongside this, the eyeball has several anatomical barriers that prevent the entry of substances. This way, diseases that affect the retina are among those that present greater difficulty in the treatment. In many cases, abnormal proliferation of blood vessels (neovascularization) occurs from the lower layers of the retina. This process damages its structure physiologically and anatomically, causing the rapid and irreversible loss of visual capacity. This work aims to develop nanosuspensions of quantum dots (QDs) conjugated to bevacizumab. Methods: Two types of QDs were produced by aqueous route, stabilized with chitosan conjugated to bevacizumab. The antiangiogenic activity was evaluated in the chorioallantoic membrane model, in which results indicated discrete activity at the doses tested. Samples were assessed for their biosafety in animals, after intravitreal administration, by means of electroretinography (ERG), intraocular pressure (IOP) measurement, histological, morphometric, and immunohistochemical evaluation. Results: No significant alterations were detected in ERG that suggests damage to retinal function by the samples. No significant changes in IOP were also detected. The histological sections did not show signs of acute inflammation, although there was evidence of late retinal damage. The immunohistochemical analysis did not detect any apoptotic bodies. Conclusion: Preliminary results suggest that QDs present potential applicability in ocular therapy, and it is necessary to better characterize their in vivo behavior and to optimize their dosage.

Development and characterization of novel ambroxol sustained-release oral suspensions based on drug-polymeric complexation and polymeric raft formation.

The aim was to develop sustained-release aqueous suspensions of ambroxol utilizing drug-polymer complexation and raft-forming formulations. Ambroxol-carrageenan (ABX-CRG) complexation was studied for the optimum binding capacity, which was used to prepare the complex by kneading and coprecipitation. The prepared complex was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry and powder X-ray diffractometry. The complex was formulated as suspensions in aqueous raft-forming vehicle of sodium alginate (NA) and calcium carbonate (CC). The suspensions differed in the molecular weight and concentration of NA, in addition to CC level and inclusion of CRG in excess of drug-polymer complexation. In 0.1 M HCl as simulated gastric fluid, the suspensions were observed for their ability to form rafts and studied for drug-release. The optimum sustained-release, raft forming and pourable formulation using high molecular weight NA, NA concentration of 18 mg/ml and CC concentration of 9 mg/ml was reached. Another optimum suspension was obtained by replacement of CC with excess CRG. However, pH dissolution profiles of the optimum suspensions revealed less pH sensitivity of the release consequent to this replacement as well as more stable ABX release upon aging. Relative to Gaviscon liquid, the optimum suspensions formed rafts of similar strength and higher resilience.

Probing in Vitro Release Kinetics of Long-Acting Injectable Nanosuspensions via Flow-NMR Spectroscopy.

Novel treatment routes are emerging for an array of diseases and afflictions. Complex dosage forms, based on active pharmaceutical ingredients (APIs) with previously undesirable physicochemical characteristics, are becoming mainstream and actively pursued in various pipeline initiatives. To fundamentally understand how constituents in these dosage forms interact on a molecular level, analytical methods need to be developed that encompass selectivity and sensitivity requirements previously reserved for a myriad of in vitro techniques. The knowledge of precise chemical interactions between drugs and excipients in a dosage form can streamline formulation development and process screening capabilities through the identification of properties that influence rates and mechanisms of drug release in a cost-effective manner, relative to long-term in vivo studies. Through this work, a noncompendial in vitro release (IVR) method was developed that distinguished the presence of individual components in a complex crystalline nanosuspension environment. Doravirine was formulated as a series of long-acting injectable nanosuspensions with assorted excipients, using low- and high-energy wet media milling methods. IVR behavior of all formulation components were monitored using a robust continuous flow-through (CFT) dissolution setup (USP-4 apparatus) with on-line 1H NMR end-analysis (flow-NMR). Results from this investigation led to a better understanding of formulation parameter influences on nanosuspension stability, surface chemistry, and dissolution behavior. Flow-NMR can be applied to a broad range of dosage forms in which specific molecular interactions from the solution microenvironment require further insight to enhance product development capabilities.

QbD Based Approach to Enhance the In-Vivo Bioavailability of Ethinyl Estradiol in Sprague-Dawley Rats.

Lyophilized nanosuspension of poorly soluble Ethinyl estradiol (EE) was fabricated to enhance its solubility and bioavailability using a quality-by-design (QbD) approach. With the help of the Ishikawa diagram, prospective risk factors were identified and screened by Placket-Burman design to investigate the effects of formulation and process variables on dependent variables. The number of cycles (X4), the concentration of soya lecithin (X5) and the concentration of tween 80 (X7) were identified as significant factors (P<0.05), which were further optimized using Central Composite Design. The mean particle size, zeta potential, drug content and entrapment efficiency of optimized lyophilized EE nanosuspension (EENPs) was 220±0.37 nm, -19.3±6.73 mV, 92.23±0.45%, 99.52±0.52%, respectively. Significantly, EENPs enhances Cmax and AUC0-t by 1.5, 1.7 folds and relative bioavailability by 2-fold with its distribution being at higher concentrations in the liver, spleen, and stomach. Thus, QbD based approach for the development of nanosuspension could be an absolute, optimistic approach to identify the critical process parameters and critical quality attributes.

Need for Bioequivalence Standards that Reflect the Clinical Importance of the Complex Pharmacokinetics of Paliperidone Palmitate Long-Acting Injectable Suspension.

Paliperidone palmitate is a second generation antipsychotic, approved for the treatment of schizophrenia in the form of the long-acting injectable (LAI) products INVEGA SUSTENNA® (once monthly injection) and INVEGA TRINZA® (once every 3 months injection). Paliperidone palmitate dissolves slowly after deep intramuscular injection before being hydrolyzed to paliperidone and absorbed into the systemic circulation. The pharmacokinetic (PK) profile of the INVEGA SUSTENNA® formulation is biphasic, comprised of an initial relatively fast zero-order input, which allows rapid attainment of therapeutic concentrations without oral supplementation; and a subsequent maintained second-stage, first-order input, allowing for once monthly administration. Changes to the manufacturing processes can substantially alter the release characteristics of paliperidone palmitate LAI and consequently its PK profile. As an example, larger or smaller particle sizes of paliperidone palmitate can result in a delayed or accelerated release of paliperidone into the systemic circulation, respectively. Such changes are clinically relevant, as transient excursions above therapeutic plasma concentrations can be associated with an increased risk of adverse effects, including tachycardia, hypotension, QT prolongation, and extrapyramidal symptoms. Conversely, a delay in attaining therapeutic plasma concentrations of paliperidone on initiation of treatment, or a return to low plasma concentrations before the end of a dosing interval during repeated dosing, increases the risk of relapse. Given the integral relationship of the PK profile to the product's clinical effects, it is important to have bioequivalence standards that reflect the complexity of the paliperidone palmitate LAI PK profile if one is to consider therapeutic equivalence based on simple bioequivalence testing. Although both the EMA and U.S. FDA have product-specific guidelines to determine bioequivalence, their requirements differ substantially. In Canada, no LAI product-specific bioequivalence guidance exists for multiphasic medication delivery systems, and the recently revised Comparative Bioavailability Standards: Formulations Used for Systemic Effects guidance applies only to oral and non-injectable formulations. We recommend that new Canadian standards be developed for multiphasic and biphasic intramuscular / subcutaneous (IM/SC) products, including paliperidone palmitate LAI products, because, similar to modified-release oral dosage forms, a different PK profile in modified-release IM/SC products can result in clinically meaningful differences in safety, efficacy, and tolerability. To ensure bioequivalence for both newly initiated and switch patients, this paper proposes bioequivalence standards that could be adopted in Canada that include two studies, a multiple-dose cross-over study, and a single-dose study with partial AUC metrics.

Fenofibrate oral absorption from SNEDDS and super-SNEDDS is not significantly affected by lipase inhibition in rats.

The effect of drug load and digestion on the solubilization and absorption of fenofibrate in self-nanoemulsifying drug delivery system (SNEDDS) was assessed in a pharmacokinetic study in rats and in an in vitro lipolysis model. SNEDDS containing fenofibrate at 75% of equilibrium solubility (Seq), a super-saturated SNEDDS (super-SNEDDS) containing fenofibrate at 150% of Seq and a super-SNEDDS suspension containing fenofibrate at 100% of Seq and an additional 50% Seq fenofibrate suspended (150% of Seq in total) were used. To assess the effect of lipid digestion on fenofibrate absorption in rats and fenofibrate solubilization during in vitro lipolysis, the lipase inhibitor orlistat was added at 1% (w/w) to the SNEDDS, resulting in six different SNEDDS: SNEDDS, super-SNEDDS and super-SNEDDS suspension with and without orlistat 1% (w/w). In vivo, super-SNEDDS had a higher Cmax and AUC0-30h compared to SNEDDS and super-SNEDDS suspension, both with and without orlistat. While orlistat did not affect fenofibrate absorption in SNEDDS and super-SNEDDS, an increase of Tmax and AUC0-30h for super-SNEDDS suspension was found when orlistat was present. During in vitro lipolysis, the addition of orlistat decreased digestion and lowered drug precipitation. Super-SNEDDS showed significantly increased absorption in rats compared to SNEDDS and super-SNEDDS suspension and the inhibition of digestion resulted in prolonged and increased absorption for the super-SNEDDS suspension.

Bioavailability testing of a newly developed clindamycin oral suspension in a pediatric porcine model.

Background: Clindamycin's bitter taste and odor is known to affect treatment adherence in children. Recently, a formulation of clindamycin HCl complexed with ion exchange resin IRP 69 was shown to mask the bitter taste. Because of the potential benefit of this formulation for children, a pilot study using a porcine model was conducted to evaluate its relative bioavailability. Methods: A randomized two-way crossover study design using six (n = 6) healthy male piglets 10-12 kg was used to evaluate the absorption profiles and pharmacokinetic parameters of clindamycin from the resinate complex formulation (Test) compared to a commercialized reference suspension. A dose of 15 mg/kg was administered orally by gastric gavage to each piglet followed by repeated blood sampling over 12 h. A wash-out period of 48 h occurred between treatments. Plasma concentration vs. time data was analyzed by non-compartmental analysis. Results: The mean relative bioavailability of clindamycin from the resinate formulation was 78.8%. A two-tailed, paired Student t test yielded a p < 0.05 for AUC∞ and Tmax parameters. A two one-sided test (TOST) suggested a difference in AUC∞ and Cmax for the Test formulation compared to the reference formulation according to the FDA's criteria for bioequivalence. Conclusion: The bioavailability of clindamycin from this novel oral formulation supports continued evaluation of the drug in humans for potential pediatric applications.

Pulmonary Dissolution of Poorly Soluble Compounds Studied in an ex Vivo Rat Lung Model.

Many inhaled drugs are poorly water soluble, and the dissolution rate is often the rate-limiting step in the overall absorption process. To improve understanding of pulmonary drug dissolution, four poorly soluble inhalation compounds (AZD5423 (a developmental nonsteroidal glucocorticoid), budesonide, fluticasone furoate (FF), and fluticasone propionate (FP)) were administered as suspensions or dry powders to the well-established isolated perfused rat lung (IPL) model. Two particle size distributions (d50 = 1.2 µm and d50 = 2.8 µm) were investigated for AZD5423. The pulmonary absorption rates of the drugs from the suspensions and dry powders were compared with historical absorption data for solutions to improve understanding of the effects of dissolution on the overall pulmonary absorption process for poorly soluble inhaled drugs. A physiologically based biopharmaceutical in silico model was used to analyze the experimental IPL data and to estimate a dissolution parameter ( kex vivo). A similar in silico approach was applied to in vitro dissolution data from the literature to obtain an in vitro dissolution parameter ( kin vitro). When FF, FP, and the larger particles of AZD5423 were administered as suspensions, drug dissolution was the rate-limiting step in the overall absorption process. However, this was not the case for budesonide, which has the highest aqueous solubility (61 µM), and the smaller particles of AZD5423, probably because of the increased surface area available for dissolution (d50 = 1.2 µm). The estimated dissolution parameters were ranked in accordance with the solubility of the drugs, and there was good agreement between kex vivo and kin vitro. The dry powders of all the compounds were absorbed more slowly than the suspensions, indicating that wetting is an important parameter for the dissolution of dry powders. A wetting factor was introduced to the in silico model to explain the difference in absorption profiles between the suspensions and dry powders where AZD5423 had the poorest wettability followed by FP and FF. The IPL model in combination with an in silico model is a useful tool for investigating pulmonary dissolution and improving understanding of dissolution-related parameters for poorly soluble inhaled compounds.

Pharmacokinetic and Metabolomic Studies with BIO 300, a Nanosuspension of Genistein, in a Nonhuman Primate Model.

Genistein is a naturally occurring phytoestrogen isoflavone and is the active drug ingredient in BIO 300, a radiation countermeasure under advanced development for acute radiation syndrome (H-ARS) and for the delayed effects of acute radiation exposure (DEARE). Here we have assessed the pharmacokinetics (PK) and safety of BIO 300 in the nonhuman primate (NHP). In addition, we analyzed serum samples from animals receiving a single dose of BIO 300 for global metabolomic changes using ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight mass spectrometry (QTOF-MS). We present a comparison of how either intramuscularly (im) or orally (po) administered BIO 300 changed the metabolomic profile. We observed transient alterations in phenylalanine, tyrosine, glycerophosphocholine, and glycerophosphoserine which reverted back to near-normal levels 7 days after drug administration. We found a significant overlap in the metabolite profile changes induced by each route of administration; with the po route showing fewer metabolic alterations. Taken together, our results suggest that the administration of BIO 300 results in metabolic shifts that could provide an overall advantage to combat radiation injury. This initial assessment also highlights the utility of metabolomics and lipidomics to determine the underlying physiological mechanisms involved in the radioprotective efficacy of BIO 300.

Exploitation of enrofloxacin-loaded docosanoic acid solid lipid nanoparticle suspension as oral and intramuscular sustained release formulations for pig.

In our previous study, enrofloxacin-loaded docosanoic acid solid lipid nanoparticles (SLNs) could be effectively delivered to cells in vitro. In this study, its properties and exploitation as possible oral and intramuscular sustained release formulations for pigs were studied after being made into suspension. The re-dispersed time and sedimentation rate of the nanosuspension were 55 s and 1, respectively. It showed good stability when stored away from light and sustained release in pH = 7.4 PBS buffer. The suspension exhibited no irritation at the injection site and good palatability. Compared with commercial injection and soluble powder, the nanosuspension increased the bioavailability of enrofloxacin by 1.63 and 2.38 folds, and extended the mean residence time (MRT) of the drug from 11.27 and 12.33 to 37.76 and 35.15 h after intragastric and intramuscular administration, respectively. These results suggest that docosanoic acid SLN suspension (DAS) might be a promising oral and intramuscular sustained release formulation to enhance the pharmacological activity of enrofloxacin.

Investigation of Drug Delivery in Rats via Subcutaneous Injection: Case Study of Pharmacokinetic Modeling of Suspension Formulations.

With the rising cost of drug research, "do more with less" has become a new emphasis in the pharmaceutical industry. Consequently, the early analysis of pharmacokinetic/pharmacodynamic, efficacy, and safety parameters for a new drug target is critical for ensuring informed decision-making as soon as possible during the drug discovery process. When absorption, distribution, metabolism, and excretion properties of compounds are suboptimal which is especially true during the early stages of drug discovery, obtaining the desired exposure can be challenging via the most common routes (oral, intravenous). Therefore, subcutaneous (SC) injection is often explored as an alternate route of delivery. Although SC injection is used widely in the industry, information about how to model and predict the absorption of drugs administered via SC injection is not readily available. In the current research, we analyzed the absorption behavior of 12 model compounds covering a wide range of physicochemical properties following SC injection. We introduced a compound-specific parameter, the absorption factor from single SC injections of suspension doses of each compound, to aid in modeling and predicting of drug absorption profiles. The pharmacokinetic models derived in this study are capable of describing and predicting the absorption properties of SC injection for individual compounds.

Bioequivalence Comparison of Pediatric Dasatinib Formulations and Elucidation of Absorption Mechanisms Through Integrated PBPK Modeling.

SPRYCEL® (Dasatinib) is a Biopharmaceutical Classification System II weakly basic drug that exhibits strong pH-dependent solubility. Dasatinib is currently presented in 2 drug product formulations as an adult immediate release tablet and a pediatric powder for oral suspension. A bioequivalence study comparing the formulations in adult healthy subjects found that overall exposure (AUC0-24) from suspension treatments was ∼9% to 13% lower, Cmax was similar, and median Tmax from powder for oral suspension was ∼30 min earlier. To understand the mechanism contributing to this behavior, a combination of biorelevant dissolution studies and physiologically based pharmacokinetic modeling was used to simulate in vivo performance. In vitro biorelevant dissolution confirmed that the rate and extent of release was similar between tablet and suspension formulations (>90% release within first 15 min). Physiologically based pharmacokinetic parameter sensitivity analysis demonstrated particular sensitivity to dosage form gastric residence time. A 12% higher AUC0-24 was simulated for tablet dosage forms with 10 to 15 min longer gastric transit relative to solutions or suspensions of small particulates (rapid gastric emptying). The corresponding narrow simulated Cmax range also agreed with observed tablet and suspension bioequivalence data. The unique physicochemical properties, absorption characteristics, and inherent differences in dosage form transit behavior are attributed to influence the dasatinib bioequivalence.

Enhanced oral bioavailability of fluvastatin by using nanosuspensions containing cyclodextrin.

BACKGROUND: In this study, fluvastatin (FVT) nanosuspensions containing cyclodextrin were developed to improve oral bioavailability. METHODS: FVT nanosuspensions containing cyclodextrin were prepared by a high pressure homogenization technique. The nanosuspensions system was then characterized by transmission electron microscopy (TEM), particle size, differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD). In addition, in vitro drug release properties, pharmacokinetics and pharmacodynamics were also investigated in detail. RESULTS: After lyophilization, the nanosuspensions could be redispersed gently and with a narrow particle size distribution, but the particle size has no obvious change. The powder X-ray diffraction and differential scanning calorimetry of FVT nanosuspensions showed that FVT existed in amorphous form in nanosuspensions. In vitro release, FVT nanosuspensions have sustained-release properties. Meanwhile, FVT nanosuspensions could significantly modify the pharmacokinetic profile and increase the bioavailability of FVT by more than 2.4-fold in comparison with the FVT capsules group. In vivo irritation test showed that there was almost no evidence of hemorrhagic mucosal erosion and intestinal villus destruction in rat gastric mucosa. CONCLUSION: The combination of nanocrystallization and cyclodextrin complexation techniques is a new attempt to formulate poorly water-soluble FVT.

Extended cell and plasma drug levels after one dose of a three-in-one nanosuspension containing lopinavir, efavirenz, and tenofovir in nonhuman primates.

OBJECTIVE: To characterize a drug-combination nanoparticle (DcNP) containing water-insoluble lopinavir (LPV) and efavirenz (EFV), and water-soluble tenofovir (TFV), for its potential as a long-acting combination HIV treatment. DESIGN: Three HIV drugs (LPV, EFV, TFV) with well established efficacy and safety were coformulated into a single DcNP suspension. Two macaques were administered one subcutaneous injection and drug concentrations in plasma and mononuclear cells (in peripheral blood and lymph nodes) were analyzed over 2 weeks. Pharmacokinetic parameters and cell-to-plasma relationships of LPV, EFV, and TFV were determined. RESULTS: This three-in-one nanoformulation provided extended concentrations of all drugs in lymph node cells that were 57- to 228-fold higher than those in plasma. Levels of all three drugs in peripheral blood mononuclear cells persisted for 2 weeks at levels equal to or higher than those in plasma. CONCLUSION: With long-acting characteristics and higher drug penetration/persistence in cells, this three-in-one DcNP may enhance therapeutic efficacy of these well studied HIV drugs due to colocalization and targeting of this three-drug combination to HIV host cells.

Preparation, Characterization and In Vivo Assessment of Repaglinide Nanosuspension for Oral Bioavailability Improvement.

AIMS AND BACKGROUND: The objective of the study was to improve the bioavailability of poorly soluble repaglinide (RPG) by preparing nanosuspension with poloxamer 188 using high pressure homogenization (HPH). The recent patents on nanocrystals (US20150337006A1) facilitated selection of drug and polymer. METHODS: Suspensions containing dissimilar sized particles were prepared by ultrasonication and HPH. The prepared aqueous suspensions were lyophilized and then characterized. Further, the dried aqueous suspensions were evaluated for drug content, solubility, in vitro dissolution, oral bioavailability study and stability study. RESULTS: RPG nanoparticles size, polydispersity index (PDI) and zeta potential were found to be 280.8 ± 15 nm, 0.279 ± 0.04 and - 25.81 ± 1.6mV, respectively. DSC and XRD results showed that RPG particles in aqueous suspensions were present in a crystalline state; however, RPG nanoparticles exhibited decreased lattice energy due to smaller particle size. Nanoparticles prepared by HPH exhibited significant improvements in solubility and dissolution rate. Oral bioavailability was found to be enhanced by 1.93 fold in comparison with that of plain RPG. The nanosuspension was found to be stable when stored at 5°C ± 3°C. CONCLUSION: The outcomes of the study revealed significant enhancement in dissolution rate and oral bioavailability of RPG due to size reduction to nano range by HPH.

Pharmacokinetics of the Oral Selective CXCR2 Antagonist AZD5069: A Summary of Eight Phase I Studies in Healthy Volunteers.

OBJECTIVE: The aim of this study was to summarise the pharmacokinetic findings from eight phase I studies in healthy volunteers given oral AZD5069, a selective small-molecule CXCR2 antagonist. METHODS: 240 healthy volunteers across eight phase I studies received single (0.1-200 mg) or multiple once- or twice-daily (10-120 mg) oral AZD5069 as solution, suspension, capsules or tablets. Pharmacokinetics were evaluated using non-compartmental analysis methods. RESULTS: AZD5069 was rapidly absorbed (time to maximum concentration ~ 2 h) under fasting conditions. A high-fat, high-calorie meal delayed and reduced the peak plasma AZD5069 concentration (Cmax) by 50%, but total exposure (AUC) was unchanged (fed:fasting geometric mean ratio 90% confidence interval within 0.80-1.25). The plasma concentration of AZD5069 declined with an initial half-life of 4 h and terminal half-life of 11 h. Steady-state plasma concentrations were achieved within 2-3 days and accumulation was ~ 1.1-fold with twice-daily dosing. Systemic exposure was approximately proportional to dose. Intra- and inter-subject variability in AUC was 3-11 and 29-64%, respectively. Less than 5% of the AZD5069 dose was excreted as parent drug in the urine. Elderly subjects had 39% higher AZD5069 AUC and 21% higher Cmax than younger adults. Japanese subjects had similar or slightly higher exposure to AZD5069 than Caucasian subjects. Co-administration with ketoconazole resulted in 2.1-fold higher AUC and 1.6-fold higher Cmax. All formulations had similar bioavailability. CONCLUSIONS: AZD5069 demonstrated predictive linear pharmacokinetics with low intra- and moderate inter-subject variability and no major influences from ethnicity, age, food or formulation. Half-life data indicated suitability for twice-daily dosing. CLINICALTRIALS. GOV IDENTIFIERS: NCT00953888, NCT01051505, NCT01083238, NCT01100047, NCT01332903, NCT01480739, NCT01735240, NCT01989520.

Early Therapeutic Drug Monitoring of Posaconazole Oral Suspension in Patients With Hematologic Malignancies.

BACKGROUND: Therapeutic drug monitoring (TDM) of posaconazole is usually performed 1 week after starting the drug because of its long half-life. However, previous studies showed that measuring the posaconazole plasma concentration (PPC) on day 3 is effective for predicting steady-state levels. The purpose of this study was to evaluate the relevance of early TDM (day 3) of posaconazole for achieving an optimal PPC. METHODS: This prospective study was conducted from September 2014 to August 2016. A total of 148 patients with acute myeloid leukemia or myelodysplastic syndromes received a 200 mg posaconazole oral suspension 3 times daily for fungal prophylaxis. During the period from September 2014 to December 2015 (control group), no dose adjustment was performed on day 3. During the period from January 2016 to Aug 2016 (early TDM group), the frequency of posaconazole 200-mg administration was increased to 4 times daily in patients whose PPC on day 3 was <400 ng/mL. The cutoff value for optimal PPC on day 8 was defined as 500 ng/mL. RESULTS: In 21 of 107 patients (20%) in the control group, PPC was <400 ng/mL on day 3. In 15 (71%) of these 21 patients, the PPC was suboptimal on day 8. In the early TDM group, the PPC was <400 ng/mL on day 3 in 4 of 41 patients (10%). After increasing the posaconazole administration frequency in these 4 patients, PPC was suboptimal on day 8 in 1 patient (25%). In both groups, 104 patients had a PPC of ≥500 ng/mL on day 3, but 7% (7/104) of these had a suboptimal level on day 8. CONCLUSIONS: Early TDM on day 3 for posaconazole suspension may help more patients achieve optimal drug levels on day 8, although TDM on day 8 is needed even in patients with optimal levels on day 3.