Extensive Hepatic First-pass Metabolism Research Articles

Enhancing Oral Bioavailability of Simvastatin Using Uncoated and Polymer-Coated Solid Lipid Nanoparticles.

Simvastatin (SVA) is a well-prescribed drug for treating cardiovascular and hypercholesterolemia. Due to the extensive hepatic first-pass metabolism and poor solubility, its oral bioavailability is 5%. Solid lipid nanoparticles (SLNs) and hydrogel-coated SLNs were investigated to overcome the limited bioavailability of SVA. Four different lipids used alone or in combination with two stabilizers were employed to generate 13 SLNs. Two concentrations of chitosan (CS) and alginate (AL) were coating materials. SLNs were studied for particle size, zeta potential, in vitro release, rheology, and bioavailability. The viscosities of both the bare and coated SLNs exhibited shear-thinning behavior. The viscosity of F11 (Chitosan 1%) at 20 and 40 rpm were 424 and 168 cp, respectively. F11 had a particle size of 260.1 ± 3.72 nm with a higher release; the particle size of F11-CS at 1% was 524.3 ± 80.31 nm. In vivo studies illustrated that F11 had the highest plasma concentration when compared with the SVA suspension and coated chitosan (F11 (Chitosan 1%)). Greater bioavailability is measured as (AUC0→24), as compared to uncoated ones. The AUC for F11, F11-CS 1%, and the SVA suspension were 1880.4, 3562.18, and 272 ng·h/mL, respectively. Both bare and coated SLNs exhibited a significantly higher relative bioavailability when compared to that from the control SVA.

Enhancing the bioavailability of clozapine through microwave-assisted formulation of a stable β-cyclodextrin inclusion complex

The low oral bioavailability of clozapine due to its poor aqueous solubility, poor dissolution rate, and extensive hepatic first-pass metabolism poses a challenge to the effective treatment of psychiatric disorders. The objective of the current research was to address the above issues by developing a clozapine inclusion complex (CLZ-IC) using the microwave irradiation method. To optimize the formulation and processing variables, namely the molar ratio of CLZ to β-CD (X1) and the irritation reaction time (X2), a 32 factorial design was performed. The phase solubility study revealed the formation of a stable inclusion complex with a stoichiometry of 1:1, suggesting that β-cyclodextrin could effectively solubilize clozapine. The characterization data confirmed the formation of the inclusion complex of clozapine in β-cyclodextrin. The optimized inclusion complex showed a solubility of 342 ± 26 µg/ml and a percentage dissolution of 91.1 ± 3.4% after four hours. The inclusion-complex tablets exhibited excellent physical properties and showed an improved in vitro dissolution profile, with 80% of the drug being released within 100 minutes, compared to marketed tablets (80% release in 300 min). In vivo pharmacokinetic studies conducted in a rat model demonstrated an increase in Cmax, area under the curve (AUC), and relative bioavailability by a factor of 2.26 with the optimized formulation, indicating a significant improvement in drug absorption compared to the marketed tablet. The techno-economic analysis suggests a cost-benefit ratio of 25.08 after 7 years, indicating the suitability for large-scale production. Overall, using Design of Experiment, in silico, and in vivo studies proved effective in optimizing the inclusion-complex formation and enhancing the bioavailability of clozapine. In conclusion, the optimized clozapine-β-cyclodextrin inclusion complex prepared using a time-saving (90 sec) and cost-effective microwave irradiation method exhibited excellent physical properties and demonstrated significant improvements in the drug's solubility, dissolution rate, and pharmacokinetic performance.

Formulation and Characterization of Nanoparticulate Drug Carrier System for Lacidipine.

Lacidipine, a calcium channel antagonist, is primarily used to treat hypertension. It is classified as a Biopharmaceutics Classification System Class II drug and exhibits an oral bioavailability of 10% due to its extensive hepatic first-pass metabolism. This research study focused on formulating lacidipine-loaded cubosomal nanovesicles developed into rapidly dissolving oral films as an alternative to overcome the downsides faced by conventional antihypertensive therapy. Lacidipine-loaded cubosomes were prepared utilizing a top-down technique using lipid and surfactant and were further developed into fast dissolving oral films. Box-Behnken design was used for the optimization of process variables to achieve minimum particle size and greater entrapment efficiency of the nanovesicles, and response data were statistically evaluated. The optimized cubosomal dispersions upon characterization reported particle size within nanorange (116.8-341 nm) and an entrapment efficiency of 88.15%-97.1%, with 91.72% of total drug content. Morphological studies revealed uniformly dispersed vesicles with cubic to spherical shape. Oral rapidly dissolving films, after evaluation, were reported to have transparent to opaque appearance with a highly porous nature, which was confirmed by scanning electron microscopic imaging and displayed uniformity in weight and thickness and reported optimum mechanical strength and considerable flexibility, with disintegration time of 37.67 ± 3.68 s and exhibited 91.44% ± 1.65% in vitro drug release after 6 min. Short-term stability studies conducted on films at 25°C ± 2°C and 60% ± 5% relative humidity for 3 months demonstrated no significant variation in morphological and mechanical properties. Therefore, lacidipine-loaded cubosomal rapid dissolving oral films may be a promising formulation approach for the management of hypertension.

Preparation and in vitro Evaluation of Rasagiline Mesylate Hybrid Nanoparticles.

Rasagiline is a selective and irreversible inhibitor of monoamine oxidase B (MAO-B) that is effective in the treatment of Parkinson's disease (PD). It had antioxidant and anti-apoptotic activity in experimental models. Moreover, it has low permeability and its oral bioavailability is weak and highly variable due to extensive first-pass hepatic metabolism (35%). This study aimed to formulate rasagiline mesylate (RM) as a lipid-polymer hybrid nanoparticle in order to enhance its permeation and increase its chance to be absorbed by lymphatic circulation to avoid metabolism and control its release. Successful formulation (PCL-2) was reached by the nanoprecipitation method using polycaprolactone with RM in the organic phase and lecithin in the aqueous phase DSPE-PEG. The lipid:polymer ratio of 24% and DSPE: lecithin of 50% resulted in stable nanoparticles having a particle size of 132±4.58 nm, polydispersity index of 0.273±0.02, zeta potential of -25.6±3.3, entrapment efficiency of 46±3.9%, and drug loading of 51.93±6.5. Results showed that the diffusion was more effective on the release profile than the degradation and resulted in a Fickian diffusion mechanism.

The Optimization and Evaluation of Flibanserin Fast-Dissolving Oral Films.

Flibanserin (FLB) is a drug used for female hypotensive sexual desire disorder approved by the FDA in August 2015. FLB exhibits extensive hepatic first-pass metabolism and low aqueous solubility, hence poor oral bioavailability. In this study, beta hydroxypropyl cyclodextrin-FLB inclusion complexes were incorporated into orally fast dissolving films. This dosage form was expected to improve FLB aqueous solubility, which would give fast onset of action and decrease presystemic metabolism, hence improving oral bioavailability. The inclusion complex at a ratio of 1:1 was prepared by the kneading method. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffractometry (XRD) were used to confirm complex formation. The Box–Behnken design (15 different formulae of FLB fast-dissolving oral films (FLBFDOFs) were utilized for the optimization of the prepared films. The Expert Design 11 program was utilized to examine the effects of three selected factors, polymer concentration (X1), plasticizer concentration (X2), and disintegrant concentration (X3) on four responses: disintegration time (DT), initial dissolution rate (IDR), dissolution efficiency (DE), and film quality (QF). Numerical optimization was performed by minimizing disintegration time (Y1), while maximizing the initial drug dissolution rate (Y2), dissolution efficiency (Y3), and the quality factor (Y4). The statistical analysis showed that X1 has a significant positive effect on the disintegration time and a significant negative effect on IDR. While X2 and X3 produced a nonsignificant negative effect on IDR. Dissolution efficiency was maximized at the middle concentration of both X2 and X3. The best film quality was observed at the middle concentration of both X1 and X2. In addition, increasing X3 leads to an improvement in film quality. The optimized film cast from an aqueous solution contains hydroxypropyl cellulose (2%) as a hydrophilic film-forming agent and propylene glycol (0.8%) as a plasticizer and cross povidone (0.2%) as a disintegrant. The prepared film released 98% of FLB after 10 min and showed good physical and mechanical properties. The optimized formula showed a disintegration time of 30 s, IDR of 16.6% per minute, DE15 of 77.7%, and QF of 90%. This dosage form is expected to partially avoid the pre-systemic metabolism with a fast onset of action, hence improving its bioavailability that favors an advantage over conventional dosage forms.

Verapamil hydrochloride loaded solid lipid nanoparticles: Preparation, optimization, characterisation, and assessment of cardioprotective effect in experimental model of myocardial infarcted rats

Verapamil, a calcium channel blocker has poor bioavailability (20–30%) owing to extensive hepatic first-pass metabolism. Hence, the major objective of this research was to improve the oral bioavailability of Verapamil by Solid Lipid Nanoparticles (V-SLNs) using high shear homogenization and ultrasonication technology. A 32 factorial design was employed to statistically optimize the formulation to get minimum particle size with maximum entrapment efficiency. The average particle size was 218 nm and the entrapment efficiency was 80.32%. The V-SLN formulation exhibited biphasic behavior with a rapid release at first, then a steady release (75–80%) up to 24 h following the Korsmeyer Peppas release model. In the Isoproterenol induced myocardial necrosis model, oral administration of V-SLNs positively modulated almost all the studied hemodynamic parameters such as left ventricular end-diastolic pressure, cardiac injury markers, and tissue architecture. The cardioprotective effect was also confirmed with histopathological studies. When compared with free drugs, in-vivo pharmacokinetic studies demonstrated a rise in t1/2, AUC0-∞, and Cmax, indicating that bioavailability has improved. These encouraging results demonstrate the promising potential of developed V-SLNs for oral delivery and thereby improve the therapeutic outcome.

A Oral Fast Dissolving Films Containing Lyophilized Labetalol HCL with Hydroxy Propyl β-Cyclodextrin/ Soluplus: Formulation Development, In Vitro Evaluation

Introduction: Labetalol HCL is an antihypertensive drug used to treat high blood pressure in the long term management of angina. Labetalol HCL is readily absorbed after oral administration. Labetalol HCl undergoes considerable hepatic first-pass metabolism due to its lipid-soluble nature. 
 Objective: The drug has an absolute bioavailability of approximately 25%. To overcome extensive hepatic first-pass metabolism the oral fast-dissolving film for labetalol HCL need to be developed. Lyophilized inclusion complexes of Labetalol HCL were developed with the hydrophilic carrier as Soluplus a Polyvinyl acetate polyethene glycol graft copolymer and Hydroxy Propyl β-cyclodextrin.
 Experimental: Lyophilized inclusion complexes of labetalol: Soluplus and labetalol HCL: HP-β-CD were prepared with 1:0.5 weight ratios. The prepared lyophilized inclusion complexes were evaluated for solubility estimation, drug content, and In-vitro dissolution study. 
 Results: The prepared inclusion complexes were characterized by Fourier transforms infrared spectroscopy and differential scanning calorimetry. Characterization of the lyophilized complex showed changed crystallinity of labetalol HCL. The fast dissolving oral film of labetalol HCL was prepared by solvent casting method by adding film-forming polymer as HPMC K 4M/ PVA in different proportions and Propylene Glycol was used as a plasticizer. The prepared batches of films were evaluated for weight variation, tensile strength, folding, endurance, disintegration time, surface pH, and drug content uniformity. All formulations prepared among F5 and F 7 showed a better result as compared to other formulations. 
 Conclusion: The study confirms the use of a lyophilized product containing Soluplus is best as that of HP-βCD for the preparation of fast dissolving film with HPMC/ PVA as film forming agent and propylene glycol as plasticizer respectively to improve dissolution rate and oral bioavailability of Labetalol HCl.

Understanding Interindividual Variability in the Drug Interaction of a Highly Extracted CYP1A2 Substrate Tizanidine: Application of a Permeability-Limited Multicompartment Liver Model in a Population Based Physiologically Based Pharmacokinetic Framework

Tizanidine, a centrally acting skeletal muscle relaxant, is predominantly metabolized by CYP1A2 and undergoes extensive hepatic first-pass metabolism after oral administration. As a highly extracted drug, the systemic exposure to tizanidine exhibits considerable interindividual variability and is altered substantially when coadministered with CYP1A2 inhibitors or inducers. The aim of the current study was to compare the performance of a permeability-limited multicompartment liver (PerMCL) model, which operates as an approximation of the dispersion model, and the well stirred model (WSM) for predicting tizanidine drug-drug interactions (DDIs). Physiologically based pharmacokinetic models were developed for tizanidine, incorporating the PerMCL model and the WSM, respectively, to simulate the interaction of tizanidine with a range of CYP1A2 inhibitors and inducers. Whereas the WSM showed a tendency to underpredict the fold change of tizanidine area under the plasma concentration-time curve (AUC ratio) in the presence of perpetrators, the use of PerMCL model increased precision (absolute average-fold error: 1.32-1.42 versus 1.58) and decreased bias (average-fold error: 0.97-1.25 versus 0.63) for the predictions of mean AUC ratios as compared with the WSM. The PerMCL model captured the observed range of individual AUC ratios of tizanidine as well as the correlation between individual AUC ratios and CYP1A2 activities without interactions, whereas the WSM was not able to capture these. The results demonstrate the advantage of using the PerMCL model over the WSM in predicting the magnitude and interindividual variability of DDIs for a highly extracted sensitive substrate tizanidine. SIGNIFICANCE STATEMENT: This study demonstrates the advantages of the PerMCL model, which operates as an approximation of the dispersion model, in mitigating the tendency of the WSM to underpredict the magnitude and variability of DDIs of a highly extracted CYP1A2 substrate tizanidine when it is administered with CYP1A2 inhibitors or inducers. The physiologically based pharmacokinetic modeling approach described herein is valuable to the understanding of drug interactions of highly extracted substrates and the source of its interindividual variability.

Comparative Pharmacokinetic Studies of Marketed Gel and Transdermal Patches Loaded with Diclofenac Diethylamine in Rabbits

Oral administration of the non-steroidal anti-inflammatory drug, Diclofenac diethylamine (DDEA) is often associated with gastrointestinal ulcers, extensive first-pass hepatic metabolism, and gastric bleeding. As an alternative to oral administration, a transdermal drug delivery system (TDDS) of DDEA was developed for topical administration, to quantify diclofenac diethylamine in plasma of rabbits for this, a sensitive Reverse Phase-high performance liquid chromatography (RP-HPLC) method was developed to compare DDEA in marketed gel and optimized formulation, using Carbamazepine as Internal standard (IS). DDEA provoke on Hypersil RP C18 column (250 mm × 4.6 mm 5 μm) using a mobile phase mixture of potassium dihydrogen buffer pH 2.5 and acetonitrile in the ratio of 30:70v/v at an isocratic flow rate of 1mL/min. The retention time of DDEA was found to be 5.3min. The calibration curve was linear over the concentration range from 50-750ng/mL of DDEA. This method was accurate for quantitative estimation of the drug in marketed gel and optimized formulation. The main aim of study is to compare Pharmacokinetic profile of diclofenac diethylamine in pharmaceutical dosage forms (Marketed gel & formulated transdermal patches) using WinNonlin software version 8.1.

Comparative Pharmacokinetic Studies of Marketed and Microsponges Gel Loaded with Diclofenac Diethylamine in Rabbits

Oral administration of the non-steroidal anti-inflammatory drug, Diclofenac Diethylamine (DDEA) is often associated with gastrointestinal ulcers, bleeding and extensive first-pass hepatic metabolism. As an alternative to oral administration, formulated microsponges-based gel of DDEA was developed for topical administration, to quantify diclofenac diethylamine in plasma of rabbits for this a sensitive Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) method was developed using carbamazepine as Internal standard (IS) and DDEA (pure drug) was provoked on Hypersil RP C18 column (250mm × 4.6mm 5µm) using a mobile phase mixture of potassium dihydrogen buffer pH 2.5 and acetonitrile in the ratio of 30:70 v/v at an isocratic flow rate of 1mL/min. The drug peak area was detection and found at 276nm. The retention time of DDEA was found to be 5.3 min. The calibration curve was linear over the concentration range of 50-750ng/ml of DDEA. This method was accurate for quantitative estimation of the drug from the marketed gel and optimized microsponge gel. The main of investigation is to compare pharmacokinetic profile of diclofenac diethylamine in pharmaceutical dosage forms (marketed gel and microsponges gel) using WinNonlin software version 8.1.

Nebulization of a polyelectrolyte-drug system for systemic hypertension treatment

Hypertension is a chronic pathology where blood pressure levels are continuously high, causing cardiac, renal, cerebral, and vascular damage leading to early morbi-mortality. This illness is the main risk factor for cardiovascular diseases and the main cause of atrial fibrillation. Atenolol (AT) is a β-1 blocker drug useful for antihypertension and antiarrhythmic treatments. However, this drug possesses low oral bioavailability associated to its low permeability and extensive hepatic first-pass metabolism. To solve the conventional AT-administration problems, oral controlled-release and transdermal delivery have been reported. In this work, an alternative AT inhalatory system administered by nebulization is presented. This system is based on an ionic complex between acidic groups of alginic acid and cationic groups of AT (AA-AT), which was obtained by spray-drying. Pharmaceutical and biopharmaceutical properties for AA-AT inhalatory administration using a jet nebulizer were investigated. The aerodynamic performance (assayed at different cup-nebulizer loadings) of the nebulized system demonstrated that around 40% of the formulation would deposit in the respiratory membrane, with mass median aerodynamic diameters of 3.4–3.6 µm. The AT carried in the AA-AT system was released adequately by ionic exchange in saline solution by permeation through a cellulose membrane. The presence of AA as polyelectrolyte conferred mucoadhesive properties to the ionic complex. Even at high relative AA-AT concentrations, no cytotoxic effect was detected in A-549 cell line. Finally, the preliminary pharmacokinetic assay in the in vivo model confirmed that AT was absorbed from the lung to the systemic circulation, with a greater plasmatic AUC compared to the pure drug (around 50% higher). Then, the system and the nebulization administration demonstrated potential for drug cardiac targeting.

Formulation Design and Evaluation of Olmesartan Mucoadhesive Buccal Tablets

The present study mucoadhesive buccal tablets of Olmesartan can be used to bypass the extensive hepatic first-pass metabolism and improve the bioavailability. The mucoadhesive Buccal tablets of Olmesartan are a drug of choice in the treatment of high blood pressure, heart failure, and diabetic kidneys. The FTIR results revealed that there was no interaction between drugs and other excipients. All the post-compression parameter was within acceptable limits. The in vitro drug release was in the range of 85.35% to 99.65% after 8 hrs the very best regression integrity (r) the best fit role model for F1 to F8 used to be zero-order and for F9 it was Higuchi matrix.

Improved Bioavailability with Dry Powder Cannabidiol Inhalation: A Phase 1 Clinical Study

Oral cannabidiol (CBD) is approved by the Food and Drug Administration (FDA) to treat patients with Dravet and Lennox-Gastaut syndromes and tuberous sclerosis complex. The therapeutic potential of oral CBD formulations is limited by extensive first-pass hepatic metabolism. Following oral administration, the inactive metabolite blood concentration is ∼40-fold higher than CBD. Inhalation bypasses the pharmacokinetic (PK) variability attributed to irregular gastrointestinal absorption and first-pass hepatic metabolism and may efficiently deliver CBD into systemic circulation. This phase 1 study compared the PK of a dry-powder inhaler (DPI) CBD formulation (10 mg powder containing 2.1 mg CBD) with an oral CBD solution (Epidiolex®, 50 mg) in healthy participants. Following a single dose of Epidiolex or DPI CBD (n=10 PK evaluable participants each), the maximum CBD concentration for the inhaled powder was 71-fold higher than that of Epidiolex while administering 24-fold less CBD. The mean time to reach maximum concentration was 3.8 min for the DPI CBD formulation compared with 122 min for Epidiolex. Both Epidiolex and DPI CBD were generally safe and well-tolerated. These data indicate that DPI CBD provided more rapid onset and increased bioavailability than oral CBD and support further investigations on the use of DPI CBD for acute indications.

Design, development and in vivo evaluation of clozapine loaded adhesive diffusion controlled system for the treatment of schizophrenia

Schizophrenia is a chronic and severe mental disorder that affects a person's thoughts, feelings, and behavior. The treatment of schizophrenic patients is a challenging task for the caregivers and the doctors. Clozapine, the first atypical antipsychotic drug, is proved to be the most significant medication for the treatment of schizophrenia. However, the oral bioavailability of clozapine is only about 27% as it undergoes extensive hepatic first-pass metabolism. Taking this into consideration, the transdermal patch of clozapine was developed in order to bypass the biotransformation of clozapine and thereby enhance its bioavailability. The present research work was intended to develop and optimize the transdermal adhesive patch of clozapine using a 3-level 2-factor experimental design. Optimized formulation was evaluated for the physicochemical characterization, fourier transform infrared, differential scanning calorimetry, permeability enhancement potential by ex vivo, skin irritation, in vivo pharmacokinetics, and stability studies. The results of the optimized formulation (F5) showed the peel strength of 428 ± 3.43 cN/cm, the flux of 106.20 ± 1.21 (μg/h/cm2), and % drug content of 99.53 ± 0.42% which was stable up to six months in accelerated condition. As per the Draize score method, the optimized transdermal patch of clozapine was found to be free from skin irritation. The pharmacokinetic result had shown the bioavailability of clozapine improved about 2.23 fold after transdermal drug delivery when compared with the oral marketed formulation. The results of the study revealed that the developed transdermal patch of clozapine can be a promising alternative that provides effective management of schizophrenia in terms of improved patient compliance.

Pharmacokinetics and brain distribution studies of perphenazine-loaded solid lipid nanoparticles

Background Perphenazine (PPZ) is a typical antipsychotic that is mainly administrated for the treatment of schizophrenia. Due to its highly lipophilic nature and extensive hepatic first-pass metabolism, its oral bioavailability is low (40%). Objective The novel nanocarriers like solid lipid nanoparticles (SLN) have been reported to be highly effective for improving the therapeutic effect of drugs. Therefore the main scope of the present investigation was the evaluation of in vivo characteristics of PPZ-SLN in terms of pharmacokinetic parameters and brain distribution. Methods The PPZ-SLN was prepared by the solvent-emulsification and evaporation method. The storage stability of PPZ-SLN and empty SLN powders was studied for 3 months. In vivo pharmacokinetic studies and brain distribution evaluations were performed following a single oral dose administration of PPZ and PPZ-SLN suspensions on male Wistar rats. An HPLC method was established and validated for the quantitative determination of PPZ in plasma and brain samples. Results The storage stability studies revealed the good storage stability of the both PPZ-SLN and empty SLN at 4 °C. Compared to PPZ suspension, the relative bioavailability and the brain distribution of PPZ-SLN were increased up to 2-fold and 16-fold, respectively. Mean residence time (MRT) and half-life (t1/2) of PPZ-SLN were significantly (p value < 0.01) increased in both plasma and brain homogenate compared to PPZ suspension. Conclusion The significant improvement in the pharmacokinetic properties of PPZ following one oral dose indicates that SLN is a promising drug delivery system for PPZ and shows a high potential for successful brain delivery of this antipsychotic.

D-α-Tocopherol polyethylene glycol succinate and stearoylmacrogol glycerides biomaterial based nanostructured mixed micelles as nose-to-brain targeting drug delivery system

ABSTRACT Olanzapine (OLA), a first atypical antipsychotic moleculethat experiences low brain permeability because of efflux by P-glycoproteins (Pgp) in the brain and extensive hepatic first-pass metabolism. The present investigation intended to design OLA-loaded mixed micelles (MM) and study their nose-to-brain targeting capability. OLA-MM was prepared by a mixture of d-α-tocopheryl polyethylene glycol 1000 succinate and gelucire®44/14 (stearoylmacrogol glycerides) (OLA-TPGL-MM) using the solvent evaporation technique. OLA-TPGL-MM was studied for various physiochemical properties, in-vitro release, ex-vivodrug permeation and in-vivo pharmacokinetic potential in male Wister rats as compared to OLA alone. Developed OLA-TPGL-MM showed particle size, negative zeta potential and entrapment efficiency of 125 nm, −5.97 mV and > 83%, respectively. OLA-TPGL-MM showed 2.12 and 1.85-fold improvement in in-vitro and ex-vivo OLA release and permeation. Substantially higher values for intranasal (i.n) OLA-TPGL-MM in drug targeting efficiency (265.36%), drug targeting index (1.82) and direct transport percentage (64.36%) indicating the potential of non-invasive OLA-loaded MM nose-to-brain targeting delivery system. TheTPGS and gelucire®44/14 based MM has a great potential for the safe and effective delivery of antipsychotic molecules in the treatment of CNS disorders.

The Interplay Between Liver First-Pass Effect and Lymphatic Absorption of Cannabidiol and Its Implications for Cannabidiol Oral Formulations.

For highly lipophilic drugs, passage into the intestinal lymphatic system rather than the portal vein following oral administration may represent a major alternative route of delivery into the general circulation. Increasing intestinal lymphatic transport provides an effective strategy to improve oral bioavailability when hepatic first-pass metabolism is a major rate-limiting step hampering access to the systemic circulation after oral dosing. The transfer of orally administered, highly lipid-soluble drugs to the lymphatic system is mediated by their association with chylomicrons, large intestinal lipoproteins that are assembled in the enterocytes in the presence of long-chain triglycerides or long-chain fatty acids. Due to its very high lipophilicity, cannabidiol (CBD) has physicochemical features (e.g. logP = 6.3) consistent with an oral absorption mediated at least in part by transport via the intestinal lymphatic system. CBD also undergoes extensive first-pass hepatic metabolism. Formulation changes favoring diversion of orally absorbed CBD from the portal to the lymphatic circulation pathway can result in reduced first-pass liver metabolism, enhanced oral bioavailability, and reduced intra- and intersubject variability in systemic exposure. In this manuscript, we discuss (1) evidence for CBD undergoing hepatic first-pass liver metabolism and lymphatic absorption to a clinically important extent; (2) the potential interplay between improved oral absorption, diversion of orally absorbed drug to the lymphatic system, and magnitude of presystemic elimination in the liver; and (3) strategies by which innovative chemical and/or pharmaceutical delivery systems of CBD with improved bioavailability could be developed.

Role of Budesonide for the Treatment of Rejection in Pediatric Liver Transplantation.

Corticosteroids are an integral part of liver transplant (LT) immunosuppression regimens but are often accompanied by many adverse effects. Budesonide is an oral corticosteroid with extensive (80%-90%) hepatic first-pass metabolism and minimal systemic absorption. The aim of this study was to examine the safety and efficacy of budesonide for management of acute cellular rejection (ACR) in pediatric LT recipients. A retrospective descriptive analysis was performed for all pediatric patients who underwent LT at our center and were prescribed oral budesonide for the treatment of ACR. Alanine aminotransferase (ALT) values and documented adverse effects were reviewed. Twenty-nine patients were prescribed budesonide for the treatment of ACR; 65.5% with biopsy-proven acute rejection and 34.5% with presumed ACR. There was a significant decrease in ALT noted from the time of rejection when compared to values 1 month (P = 0.0011), 3 months (P = 0.0003), and 6 months (P = 0.0001) after treatment with budesonide. There was no difference noted between patient baseline ALT levels before rejection when compared to 1, 3, and 6 months posttreatment values suggesting resolution of rejection. Three patients required conversion from budesonide to systemic steroids. There were no discontinuations of budesonide secondary to adverse effects. Oral budesonide may be a promising alternative to systemic corticosteroids for the management of mild/moderate ACR and for empiric treatment of ACR in select pediatric LT recipients. Data from this study may provide the foundation for larger, prospective, multicenter trials to assess the effectiveness of budesonide in the treatment of ACR.

Effect of binary combinations of solvent systems on permeability profiling of pure agomelatine across rat skin: a comparative study with statistically optimized polymeric nanoparticles

Objective: Agomelatine (AGM), an antidepressant drug has low biological half-life coupled with extensive hepatic first-pass metabolism. For effective treatment of depression, daily medication is required but irregular dose intake occurs due to psychological illness which can be overcome by development of transdermal drug delivery system. But for effective transdermal delivery permeation of AGM through stratum corneum is a crucial step. Thus present study was intended to formulate and optimize polymeric nanoparticles of agomelatine and to compare the effect of binary combinations of solvent system on permeability profiling of pure agomelatine with statistically optimized polymeric nanoparticles.Methods: Polymeric agomelatine nanoparticles (AGM-PNPs) were prepared by nano-precipitation method which was further optimized by experimental design and characterized by FTIR, DSC, XRD and SEM study while ex-vivo study was performed on adult male wistar rats.Results: The optimized formulation has particle size in nano range (107.64 nm) with low PDI (0.209), stable zeta potential (−15 mV) and high entrapment efficiency (81.91%). Ex-vivo analysis of optimized nanoparticles suggests that nanoparticles permeate faster compared to plain AGM, while, permeation profile of AGM was enhanced when combination of solvent systems were used. It was observed that among various solvent system 33% PG-ethanol showed maximum flux (148.48 ± 3.24 µg/cm2/h) and least lag time (4.04 ± 0.12 h). The flux was further enhanced (180.98 ± 2.54 µg/cm2/h) when 5%v/v transcutol-HP was added as penetration enhancer.Conclusion: The above observations concluded that binary combination of 33% PG-ethanol with 5 %v/v transcutol-HP can serve as a solvent system of choice for effective transdermal delivery of agomelatine via nanoparticulate system.

Nose-to-brain Delivery of Natural Compounds for the Treatment of Central Nervous System Disorders

Several natural compounds have demonstrated potential for the treatment of central nervous system disorders such as ischemic cerebrovascular disease, glioblastoma, neuropathic pain, neurodegenerative diseases, multiple sclerosis and migraine. This is due to their well-known antioxidant, anti-inflammatory, neuroprotective, anti-tumor, anti-ischemic and analgesic properties. Nevertheless, many of these molecules have poor aqueous solubility, low bioavailability and extensive gastrointestinal and/or hepatic first-pass metabolism, leading to a quick elimination as well as low serum and tissue concentrations. Thus, the intranasal route emerged as a viable alternative to oral or parenteral administration, by enabling a direct transport into the brain through the olfactory and trigeminal nerves. With this approach, the blood-brain barrier is circumvented and peripheral exposure is reduced, thereby minimizing possible adverse effects. Herein, brain-targeting strategies for nose-to-brain delivery of natural compounds, including flavonoids, cannabinoids, essential oils and terpenes, will be reviewed and discussed. Brain and plasma pharmacokinetics of these molecules will be analyzed and related to their physicochemical characteristics and formulation properties. Natural compounds constitute relevant alternatives for the treatment of brain diseases but often require loading into nanocarrier systems to reach the central nervous system in sufficient concentrations. Future challenges lie in a deeper characterization of their therapeutic mechanisms and in the development of effective, safe and brain-targeted delivery systems for their intranasal administration.