Influence of Drug Property and Product Design on In Vitro–In Vivo Correlation of Complex Modified-Release Dosage Forms

The present study examines how drug's inherent properties and product design influence the evaluation and applications of in vitro–in vivo correlation (IVIVC) for modified-release (MR) dosage forms consisting of extended-release (ER) and immediate-release (IR) components with bimodal drug release. Three analgesic drugs were used as model compounds, and simulations of in vivo pharmacokinetic profiles were conducted using different release rates of the ER component and various IR percentages. Plasma concentration–time profiles exhibiting a wide range of t_max and maximum observed plasma concentration (C_max) were obtained from superposition of the simulated IR and ER profiles based on a linear IVIVC. It was found that depending on the drug and dosage form design, direct use of the superposed IR and ER data for IVIVC modeling and prediction may (1) be acceptable within errors, (2) become unreliable and less meaningful because of the confounding effect from the non-negligible IR contribution to C_max, or (3) be meaningless because of the insensitivity of C_max to release rate change of the ER component. Therefore, understanding the drug, design and drug release characteristics of the product is essential for assessing the validity, accuracy, and reliability of IVIVC of complex MR products obtained via directly modeling of in vivo data.     

The Effect of Drug Content Reduction on the In Vitro and In Vivo Properties of Levonorgestrel-Releasing Intravaginal Rings

Intravaginal rings (IVRs) are an option for continuous administration of drugs in women. However, a considerable amount of excess drug often remains in the ring upon removal. The current study focuses on comparing 2 IVRs releasing levonorgestrel (LNG). Both formulations were designed to release 40 μg of LNG daily, however, with a significant difference in the total amount of drug (10.6 vs. 176.9 mg). Numerical simulations and in vitro release rate testing were utilized in designing the IVRs and confirming the similarity of drug release. Moreover, a pharmacokinetic (PK) study was performed in 13 healthy Japanese women to investigate both formulations during the intended wearing period of 28 days. The primary PK metrics was the average concentration of LNG in plasma at defined time points under stable conditions. Statistical evaluation of the ratio of the main PK metrics indicated values almost in the bioequivalence range. Furthermore, drug content determinations for used and unused IVRs were analyzed for confirming the expected drug delivery in vivo. In summary, it was shown that with proper design, even major differences in the total drug content of IVR formulations might not result in significant effects in the in vitro and in vivo release properties.     

In Vitro Release—In Vivo Microbiological and Toxicological Studies on Ketoconazole Lipid Granules

In some multidrug therapy programs, ketoconazole (KTZ) may be administered with some antacids that could modify its dissolution rate and reduce its absorption, thus leading to therapeutic failures. The primary aim of this study was to evaluate the influence of Compritol HD5 ATO and Compritol 888 ATO on this interaction in comparison with commercial KTZ tablets. The second aim was to prepare lipid granules of KTZ that could be an alternative to the commercial formulation. Therefore, six KTZ sustained-release granules were prepared with different lipid concentrations, because they were found to be more suitable than tablets that are dissolved only in gastric medium. The results confirmed that the dissolution rate of KTZ granules was significantly reduced in the presence of antacids. The ideal formulation was selected as granules including 5% of Compritol lipids in relation to the suitability of the target profile. Therapeutic effects of orally administered, ideal KTZ granule formulations, and commercial tablets were evaluated in vivo by the experimental model of murine vulvo-vaginal candidiasis (VVC) with and without antacids. It was found that formulations were very effective on VVC, and the therapeutic effect decreased significantly in the presence of antacids. Histopathological studies were carried out for vagina, stomach, and liver tissues and hepatoxicity was also examined. The levels of reduced glutathione (GSH) were measured to assess the oxidative stress induced by KTZ and function of the liver. It was observed that orally administered formulations of KTZ were successful in treating candidiasis in mice without irritancy in stomach. However, liver tissues were damaged. The decreased GSH levels indicated toxicity in our study. This study suggested that in vitro release and in vivo microbiological-toxicological properties of KTZ were affected by antacids and drug-excipient interactions. Lipid granules of KTZ prepared with Compritol 888 ATO could be proposed as a new KTZ solid dosage form with optimum dissolution and therapeutic characteristics.     

In Vitro–In Vivo Correlation on Delivery of Drug Candidates to Articular Cartilage

PURPOSE: In the treatment of osteoarthritis (OA), some of the therapeutic approaches require delivery of drug(s) to the diseased cartilage. Presence of adequate drug levels in the cartilage is one of the important criteria in selection and ranking of lead compounds. The purpose of this study was to investigate the correlation in cartilage compound levels between in vitro experiments and in vivo animal studies. MATERIALS AND METHODS: Bovine cartilage samples were incubated with test compounds of various concentrations in a culture medium, in the absence or presence of 25 mg/ml of serum albumin which served as an artificial synovial fluid (SF). The test compounds were also dosed to rabbits, the animal model used for efficacy studies, over a six-week treatment period. Test article concentrations in plasma, SF, and cartilage were determined by LC/MS/MS analysis. RESULTS AND CONCLUSIONS: A correlation in cartilage drug concentration was observed between in vitro and in vivo studies. Plasma protein binding and the test article's affinity to cartilage were the major determining factors for drug delivery to cartilage in vivo.     

In Vitro and In Vivo Investigation on PLA–TPGS Nanoparticles for Controlled and Sustained Small Molecule Chemotherapy

Purpose

The aim of this work was to evaluate in vivo poly(lactide)-d-α-tocopheryl polyethylene glycol 1,000 succinate nanoparticles (PLA–TPGS NPs) for controlled and sustained small molecule drug chemotherapy.

Methods

The drug-loaded PLA–TPGS NPs were prepared by the dialysis method. Particle size, surface morphology and surface chemistry, in vitro drug release and cellular uptake of NPs were characterized. In vitro and in vivo therapeutic effects of the nanoparticle formulation were evaluated in comparison with Taxol®.

Results

The PLA–TPGS NP formulation exhibited significant advantages in in vivo pharmacokinetics and xenograft tumor model versus the PLGA NP formulation and the pristine drug. Compared with Taxol®, the PLA–TPGS NP formulation achieved 27.4-fold longer half-life in circulation, 1.6-fold larger area-under-the-curve (AUC) with no portion located above the maximum tolerance concentration level. For the first time in the literature, one shot for 240 h chemotherapy was achieved in comparison with only 22 h chemotherapy for Taxol® at the same 10 mg/kg paclitaxel dose. Xenograft tumor model further confirmed the advantages of the NP formulation versus Taxol®.

Conclusions

The PLA–TPGS NP formulation can realize a way of controlled and sustained drug release for more than 10 days, which relieves one of the two major concerns on cancer nanotechnology, i.e. feasibility.     

Hepatic Metabolism and Disposition of Baicalein via the Coupling of Conjugation Enzymes and Transporters—In Vitro and In Vivo Evidences

Baicalein (Ba) was found to be subject to serious first-pass metabolism after oral administration. We previously revealed the important role of intestine in the low oral bioavailability of Ba. The present study aims to evaluate the hepatic metabolism and disposition of Ba. Ba was given to Sprague-Dawley rats through bolus or infusion via intravenous or intra-portal route of administrations. Both plasma and bile samples at different time intervals were obtained. Concentrations of Ba and potential metabolites in the collected samples were analyzed with HPLC/UV and identified by LC/MS/MS, respectively. Plasma concentration versus time profiles of Ba obtained from intravenous and intra-portal administrations were compared to estimate the extent of hepatic metabolism. In addition, transport studies of baicalein-7-glucuronide (BG), one of the major metabolites of Ba, were carried out using transfected cell systems overexpressing various human organic anion-transporting polypeptide (OATP) isoforms to estimate the specific transporters involved in the hepatic disposition of Ba metabolites. The results showed that liver, in addition to intestine, also conferred extensive metabolism to Ba. Several mono- and di-conjugates of Ba, which were mainly glucuronides, sulfates, and methylates, were found in bile. The transport study demonstrated that besides MRPs and BCRP, human OATP2B1 and OATP1B3 in liver might also mediate the secretion of BG to bile. In summary, liver plays an important role in the metabolism of Ba and transport of its conjugated metabolites.     

Potential of Cationic-Polymeric Nanoparticles for Oral Delivery of Naringenin: In Vitro and In Vivo Investigations

The objective of the study was to improve the bioavailability and anticancer potential of naringenin (NRG) by developing a drug-loaded polymeric nanodelivery system. NRG-loaded eudragit E100 nanoparticle (NRG-EE100-NPs) system was developed and physicochemically characterized. In vivo pharmacokinetic and in vitro cytotoxicity abilities of the NRG-EE100-NPs were investigated. In vivo anticancer activity was evaluated in murine BALB/c mice-bearing colorectal tumor. The NRG-EE100-NPs had an optimum mean particle size (430.42 ± 5.78 nm), polydispersity index (0.283 ± 0.089) with percent entrapment efficiency (68.83 ± 3.45%). The NRG-EE100-NPs demonstrated significant higher bioavailability (～96-fold; p <0.05) as well as cytotoxicity (～16-fold; p <0.001) as compared to free NRG. Furthermore, NRG-EE100-NPs indicated significant tumor suppression (p <0.01) subsequently improvement in survival rate compared to free NRG in vivo. Thus, the physicochemical properties and colorectal cancer efficacy of NRG were improved by successful encapsulating in cationic-polymeric nanoparticle system.     

An In Vitro and In Vivo Comparison of Solid and Liquid–Oil Cores in Transdermal Aconitine Nanocarriers

This study compared transdermal aconitine delivery using solid lipid nanoparticles (SLN) and microemulsion (ME) vehicles. Aconitine‐loaded SLN and ME were formulated with the same surfactant, cosurfactant, and water content, with an equal amount of oil matrix (ATO 888 for SLN and ethyl oleate for ME). These nanosized formulations (70–90 nm) showed suitable pH values and satisfactory skin tissue biocompatibility. SLN contained a higher concentration of smaller nanoparticles, compared with that in ME. Neither of the nanocarriers penetrated across excised skin in their intact form. In vitro transdermal delivery studies found that transdermal aconitine flux was lower from SLN than from ME (p < 0.05), but skin aconitine deposition was higher using SLN (p < 0.05). Fluorescence‐activated cell sorting indicated that in vitro uptake of fluorescently labeled SLN by human immortalized keratinocyte (HaCaT) cells was greater than that of ME, indicating that a transcellular pathway may contribute to cutaneous drug absorption more effectively from SLN. In vivo studies found that these formulations could loosen stratum corneum layers and increase skin surface crannies, which may also enhance transdermal aconitine delivery. SLN produced a more sustained aconitine release, indicating that compared with ME, this transdermal delivery vehicle may reduce the toxicity of this drug. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3602–3610, 2014     

In Vitro and In Vivo Correlation of Hepatic Fraction of Metabolism by P450 in Dogs

1-Aminobenzotriazole (ABT) has been widely used as a nonspecific mechanism-based inhibitor of cytochrome P450 (P450) enzymes. It is extensively used in preclinical studies to determine the relative contribution of oxidative metabolism mediated by P450 in vitro and in vivo. The aim of present study was to understand the translation of fraction metabolized by P450 in dog hepatocytes to in vivo using ABT, for canagliflozin, known to be cleared by P450-mediated oxidation and UDP-glucuronosyltransferases–mediated glucuronidation, and 3 drug discovery project compounds mainly cleared by hepatic metabolism. In a dog hepatocyte, intrinsic clearance assay with and without preincubation of ABT, 3 Lilly compounds exhibited a wide range of fraction metabolized by P450. Subsequent metabolite profiling in dog hepatocytes demonstrated a combination of metabolism by P450 and UDP-glucuronosyltransferases. In vivo, dogs were pretreated with 50 mg/kg ABT or vehicle at 2 h before intravenous administration of canagliflozin and Lilly compounds. The areas under the concentration-time curve (AUC) were compared for the ABT-pretreated and vehicle-pretreated groups. The measured AUC_ABT/AUC_veh ratios were correlated to fraction of metabolism by P450 in dog hepatocytes, suggesting that in vitro ABT inhibition in hepatocytes is useful to rank order compounds for in vivo fraction of metabolism assessment.     

Influence of Dissolution Media and Presence of Alcohol on the In Vitro Performance of Pharmaceutical Products Containing an Insoluble Drug

The purpose of this investigation is to determine how the dissolution media may influence the release rate of an insoluble drug in in vitro conditions. Some oral dosage forms containing ibuprofen, a molecule that shows pH-dependent solubility, are tested. They are evaluated in different media to simulate the gastrointestinal transit at paddle rotation speeds of 50 and 100 rpm. Moreover, the potential effect of different ethanol concentrations on drug release is tested. The dissolution profiles of the tablets show a similar behavior in water (pH 1.0) and phosphate buffer (pH 4.5) where the 2 doses are not completely dissolved. The soft capsules show a different behavior: a certain amount of ibuprofen, which is in solution inside the capsule, reprecipitates in water and in the pH 4.5 buffer. Instead, ibuprofen dissolves rapidly in the pH 6.8 buffer from all the formulations. In the water-ethanol solutions, the dissolution curves show a valuable increase in the drug dissolved at higher ethanol concentrations.     

In Vitro Lipolysis and Intestinal Transport of β-Arteether-Loaded Lipid-Based Drug Delivery Systems

Purpose

We aimed to assess the fate of β-arteether lipid-based drug delivery systems (AE-LBDDS) in terms of resistance to lipolysis and permeation across intestinal cells.

Methods

AE-LBDDS contained Tween 80 or Cremophor EL as surfactants, ethanol, Maisine 35-1 and vegetable oil. The solubilization behavior of AE was investigated during dynamic in vitro lipolysis. The permeation of AE-LBDDS was evaluated using Caco-2, HT29-MTX and M cell monolayers.

Results

A higher level of AE precipitation was observed for formulations containing Cremophor EL (~30%) compared to formulations containing Tween 80 (~10%) after lipolysis. However, rapid re-dissolution of the precipitated AE from LBDDS containing Cremophor EL in the intestinal biorelevant media was observed. The transport of AE loaded in LBDDS was enhanced in comparison to that of free drug due to the increased AE solubility. The apparent permeability of all AE-LBDDS across Caco-2 cell monolayers was approximately 3.10^?6 cm/s. A decrease in the permeability was observed at 4°C. M cells did not influence the transport of AE-LBDDS, and mucus decreased AE permeability when formulated with Tween 80. Furthermore, AE is not a P-glycoprotein substrate.

Conclusion

LBDDS that are partly resistant to in vitro lipolysis significantly increased the transport of AE across intestinal cell monolayers.     

Contribution of Human Liver and Intestinal Carboxylesterases to the Hydrolysis of Selexipag In Vitro

In liver microsomes, selexipag (NS-304; ACT-293987) mainly undergoes hydrolytic removal of the sulfonamide moiety by carboxylesterase 1 (CES1) to yield the pharmacologically active metabolite MRE-269 (ACT-333679). However, it is not known how much CES in the liver and intestine contributes to the hydrolysis of selexipag or how selexipag is metabolized in the intestine, including by hydrolysis. To obtain a better understanding of selexipag metabolism in humans, we determined the percentage contribution of CES1 and carboxylesterase 2 (CES2) to the hydrolysis of selexipag and 7 of its analogs with different sulfonamide moieties and evaluated its nonhydrolytic metabolism in human liver microsomes and human intestinal microsomes (HIMS). For selexipag, the percentage contributions of CES1 and CES2 in human liver microsomes were 77.0% and 9.99%, respectively, while the percentage contribution of CES2 in HIMS was 100%. In HIMS, the rate of hydrolysis of selexipag was the lowest among the compounds tested, and no difference between the presence and absence of nicotinamide adenine dinucleotide phosphate was noted. We infer from these results that selexipag is likely to be hydrolyzed by CES2 as well as CES1, and only selexipag itself and the MRE-269 produced by hydrolysis in the intestine would be absorbed after oral administration.     

Preparation and In Vitro Analysis of Microcapsule Thalidomide Formulation for Targeted Suppression of TNF-α

Recent studies have implicated the cytokine tumor necrosis factor-alpha (TNF-α) in the inflammation associated with Crohn's disease (CD). Thalidomide has been shown to decrease this inflammation by the suppression of TNF-α secretion. However, side effects associated with thalidomide have precluded its widespread usage. In the present study we investigated the efficacy of a “targeted delivery approach” for thalidomide at the site of inflammation. We observed that alginate-poly-l-lysine-alginate (APA) polymer-based microcapsule formulations that encapsulate thalidomide could be designed. These capsules could be delivered at target sites where they almost entirely suppress TNF-α secretion in lipopolysaccharide activated RAW 264.7 macrophage cells in vitro. These findings indicate that targeted delivery of thalidomide using APA capsules could facilitate its usage in reducing the inflammation associated with chronic conditions such as Crohn's disease and ulcerative colitis.     

Methadone Metabolism and Drug-Drug Interactions: In Vitro and In Vivo Literature Review

Methadone is utilized for the treatment of individuals with opiate dependence. Methadone undergoes N-demethylation by multiple cytochrome P450 (CYP) enzymes including CYP3A4, CYP2B6, CYP2C19, CYP2D6, CYP2C9, and CYP2C8. In vivo, polymorphism effects on methadone systemic exposure have been noted for CYP2B6, CYP3A4, and CYP2D6. Clinical drug interaction studies with antiviral drugs in methadone maintenance treatment patients yield varying results on methadone pharmacokinetics and pharmacodynamics. In general, CYP inhibitors altered methadone exposure with no adverse effects. CYP inducers generally decreased methadone exposure with some reports of withdrawal symptoms in the subjects. Interaction studies with antiviral drug combinations yielding differing results depend on the enzyme(s) affected. For certain antiviral medicines which are dual inhibitor(s) and inducer(s) for CYP enzymes, their effect on methadone pharmacokinetics can change with time since the effect of induction is usually delayed compared to the effect of inhibition.     

Health Effects of Ambient Particulate Matter—Biological Mechanisms and Inflammatory Responses to In Vitro and In Vivo Particle Exposures

In this article, we review and analyze different modes of exposure to ultrafine particles in order to assess particle-induced inflammatory responses and the underlying mechanisms in vitro and in vivo. Based on results from monocytic cells cultured under submerged conditions, we discuss (1) the impact of particle properties such as surface area and oxidative potential on lipid metabolism as a highly sensitive regulatory pathway and (2) the interference of diesel exhaust particles with toll-like receptor-mediated inflammatory responses. Furthermore, new developments of air–liquid interface exposure used as an alternative approach to simulate cell particle interactions are presented. In addition to the in vitro approaches, animal exposure studies are described that apply selected mouse models to elucidate potential allergic and inflammatory pulmonary responses and mast-cell-related mechanisms after particle exposure. Long-term inhalation of ultrafine particles might lead to irreversible changes in lung structure and function. Clinical studies addressing the characteristics of inflammatory airway cells are a promising approach to understand underlying pathophysiological mechanisms in chronic obstructive pulmonary disease. Finally, a potential outcome of human particle exposure is chronic cough in children. Here, discrimination between asthmatic and nonasthmatic cough by means of immunological parameters appears to be an important step toward improving diagnosis and therapy.     

In Vitro–In Vivo Correlations of Scalable PLGA-Risperidone Implants for the Treatment of Schizophrenia

Purpose  

Nonadherence to antipsychotic medications is a major obstacle preventing optimal outcomes for patients with schizophrenia. Extended release systems exist in the form of depot injections, but these formulations exhibit several disadvantages. To address these concerns, we previously demonstrated proof of concept for an antipsychotic implant containing risperidone and the biodegradable polymer poly(lactic-co-glycolic) acid (PLGA).     

In Vitro Digestion of the Self-Emulsifying Lipid Excipient Labrasol® by Gastrointestinal Lipases and Influence of its Colloidal Structure on Lipolysis Rate

Pharmaceutical Research - Labrasol® is a self-emulsifying excipient used to improve the oral bioavailability of poorly water-soluble drugs. It is a mixture of acylglycerols and PEG esters,...     

Formulation and Characterization of Spray-Dried Powders Containing Vincristine-Liposomes for Pulmonary Delivery and Its Pharmacokinetic Evaluation From In Vitro and In Vivo

Vincristine (VCR) has been used in the treatment of lung cancer. To improve its efficacy, the designs of elevating lung exposure to drug and decreasing the clearance with extended time were brought out. Pulmonary delivery is regarded as a good choice in pulmonary diseases treatment. Spray-drying is a technology for the preparation of drugs that can be delivered to lung via a dry powder inhaler. The results showed an appropriate particle size and shape for the pulmonary delivery. The aerosol behaved a sustained-release profile while VCR solution released rapidly within 10 h. The antitumor activity was characterized by 3-(4, 5-dimethylthiazol-2-yl) -2, 5-diphenyltetrazolium bromide assay, and half maximal inhibitory concentration values of VCR-liposomes spray-dried powder were 24.42 ± 1.88 nM and 55.28 ± 4.76 nM in MCF-7 and A549 cells, respectively. Compared with the free VCR, the aerosol performed better pharmacokinetic behavior: increased maximum concentration (630.8%) and systemic exposure (429.6%) and decreased elimination half-life (81.1%). The clearance was decreased by 83.2%. Comprehensively, the pulmonary delivery seemed to be a recommendable way to effectively treat the pulmonary disease.     

Diosmin Nanocrystal–Loaded Wafers for Treatment of Diabetic Ulcer: In Vitro and In Vivo Evaluation

This work aimed at loading of diosmin nanocrystals into alginate-based wafers for treatment of highly exuding diabetic ulcer in rats using topical route of administration. For this purpose, different formulation variables and preparation techniques to enhance the flexibility and adhesion properties of the prepared sodium alginate (SA) wafers were carried out. The prepared wafers were characterized regarding hydration capacity, bioadhesion, scanning electron microscope, and Fourier-transform infrared spectroscopy. Efficacy of treating diabetic ulcer was studied using diabetic-induced rat model using streptozotocin. Results obtained showed that using SA:gelatin with 1.5%/1.5% w/w gave acceptable wafers with a sustained release of diosmin over 8 h. A complete re-epithelialization, well-organized dermal layers, well-formed granulation tissue, and mature collagen bundles were observed in treated rats. It was concluded that combination of gelatin with SA provided an excellent wafer as a promising medicated wound dressing holding diosmin nanocrystals while maintaining its stability.     

In Vitro Skin Permeation of Osthol from Hydro-Alcohofic Gel Formulations

Aim To evaluate the in vitro percutaneous absorption behavior of osthol from a series of hydro-alcoholic gel formulations containing three penetration enhancers through excised human skin (stratum cormeum and epidermis,SCE). Methods Excised human skin was mounted in Franz-type diffusion cells. The samples withdrawn from the receptor cell were analyzed for osthol content by high-performance liquid chromatography (HPLC). Results The enhancers azone, menthol and chenopodium increased the osthol percutaneous steady-state fluxes 3.12, 2.00 and 1.25 times those of the enhancer-free formulations (controls), separately. Conclusions The main enhancement mechanism of the skin penetration enhancers azone, menthol and chenopodium is to destroy the barrier fimction of stratum corneum, reducing the resistance of drug transport through the skin and increasing the diffusion coefficients of osthol.