Solid Dispersion Preparation by Different Methods to Improve Solubility & Dissolution Simvastatin

The improvement of a pure drug's solubility and dissolution rate in the treatment of hyperlipidemia. Simvastatin is a 5-percent absolute bioavailability selective competitive inhibitor of HMG Co-A reductase. For the selection of the carrier, a preliminary solubility investigation of solid dispersion was performed, and solid dispersion was made using Hydroxy Propyl Methyl Cellulose (HPMC) and gum acacia. Solid dispersion of medication with polymer was created and studied for solubility and in-vitro dissolution profile. Solid dispersion of drug with polymer has shown an increase in solubility and improved dissolution rate. On the obtained formulations, further FTIR, X-Ray, Scanning electron microscopy, and Differential scanning calorimetry experiments were conducted. The existence of amorphous form in a solid dispersion made with polymer in a 1:5 ratio is verified by characterization research. The research also showed that using a solid dispersion approach with Polymer, the dissolving rate of a pure medication may be significantly increased.

Determination of the Peptide AWRK6 in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and Its Application to Pharmacokinetics

AWRK6 was a synthesized peptide developed based on the natural occurring peptide dybowskin-2CDYa, which was discovered in frog skin in our previous study. Here, a quantitative determination method for AWRK6 analysis in rat plasma by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established and validated following U.S. FDA guidelines. A combination of plasma precipitation and liquid–liquid extraction was applied for the extraction. For pharmacokinetics study, the rats were administrated with AWRK6 via intraperitoneal and intravenous injection. The prepared plasma samples were separated on an ODS column and analyzed by tandem MS using precursor-to-product ion pairs of m/z: 533.4→84.2 for AWRK6 and m/z: 401.9→101.1 for internal standard Polymyxin B sulfate in multiple reaction monitoring mode. AWRK6 concentrations in rat plasma peaked at about 1.2 h after intraperitoneal injections at 2.35, 4.7 and 9.4 mg/kg bodyweight. The terminal half-life was around 2.8 h. The absolute bioavailability of AWRK6 was 50% after 3 doses via injection, and the apparent volume of distribution was 4.884 ± 1.736 L. The obtained determination method and pharmacokinetics profiles of AWRK6 provides a basis for further development, and forms a benchmark reference for peptide quantification.

(+)-9-Trifluoroethoxy-α-Dihydrotetrabenazine as a Highly Potent Vesicular Monoamine Transporter 2 Inhibitor for Tardive Dyskinesia

Valbenazine and deutetrabenazine are the only two therapeutic drugs approved for tardive dyskinesia based on blocking the action of vesicular monoamine transporter 2 (VMAT2). But there exist demethylated inactive metabolism at the nine position for both them resulting in low availability, and CYP2D6 plays a major role in this metabolism resulting in the genetic polymorphism issue. 9-trifluoroethoxy-dihydrotetrabenazine (13e) was identified as a promising lead compound for treating tardive dyskinesia. In this study, we separated 13e via chiral chromatography and acquired R,R,R-13e [(+)-13e] and S,S,S-13e [(−)-13e], and we investigated their VMAT2-inhibitory activity and examined the related pharmacodynamics and pharmacokinetics properties using in vitro and in vivo models (+)-13e displayed high affinity for VMAT2 (Ki = 1.48 nM) and strongly inhibited [3H]DA uptake (IC50 = 6.11 nM) in striatal synaptosomes. Conversely, its enantiomer was inactive. In vivo, (+)-13e decreased locomotion in rats in a dose-dependent manner. The treatment had faster, stronger, and longer-lasting effects than valbenazine at an equivalent dose. Mono-oxidation was the main metabolic pathway in the liver microsomes and in dog plasma after oral administration, and glucuronide conjugation of mono-oxidized and/or demethylated products and direct glucuronide conjugation were also major metabolic pathways in dog plasma. O-detrifluoroethylation of (+)-13e did not occur. Furthermore, CYP3A4 was identified as the primary isoenzyme responsible for mono-oxidation and demethylation metabolism, and CYP2C8 was a secondary isoenzyme (+)-13e displayed high permeability across the Caco-2 cell monolayer, and it was not a P-glycoprotein substrate as demonstrated by its high oral absolute bioavailability (75.9%) in dogs. Thus, our study findings highlighted the potential efficacy and safety of (+)-13e in the treatment of tardive dyskinesia. These results should promote its clinical development.

FARMACOCINÉTICA Y BIODISPONIBILIDAD ABSOLUTA DE MARBOFLOXACINA EN BÚFALOS (Bubalus bubalis)

The aim of this study was to evaluate the pharmacokinetic behaviour and the absolute bioavailability of marbofloxacin (MFX) in adult water buffaloes and to estimate the pharmacokinetic parameters for calculating the therapeutic dose in this animal species. Six adult buffaloes (3 males and 3 females) where treated by intravenous (IV) and subcutaneous (SC) route with a 10% experimental MFX injectable formulation at the dose of 2 mg/kg. After administration blood samples were drawn at pre-established times and MFX plasma concentrations where determined by microbiologic method. The pharmacokinetic analysis was made by compartmental analysis. After IV administration MFX presented a clearance of 198.4 ± 21.0 mL.kg.h and a half-life of elimination of 7.64 ± 3.29 h. After SC administration marbofloxacin presented a half-life of elimination of 8.5 ± 2.42 h, reaching it maximum plasma concentration (1.67 ± 0.516 μg/mL) at 1.69 ± 0.231 h, with a bioavailability of 80.8 ± 11.2 %. The estimated values of clearance and bioavailability will be employed in further studies for calculating the therapeutic dose of MFX in water buffaloes.

898 Intratumoral administration of NL-201, an alpha-independent IL-2/15 receptor agonist, inhibits the growth of both injected and uninjected tumors in preclinical models

BackgroundNL-201 is a potent, selective, and long-acting computationally designed alpha-independent agonist of the IL-2 and IL-15 receptors that is being developed as an immunotherapy for cancer. Intravenous NL-201 administration is active in numerous pre-clinical tumor models. Here, we report data demonstrating favorable tolerability, pharmacokinetics, and antitumor activity of NL-201 after intratumoral (IT) administration in syngeneic murine tumor models.MethodsMice were implanted with syngeneic colorectal tumors in a single tumor (right flank) or bilateral tumor model (right and left flank). Once tumors were established, mice were randomized to receive IT or intravenous (IV) NL-201, or IV vehicle as control. Tumor volumes (mm3) and bodyweights were measured twice weekly, and mice were monitored for abnormal clinical signs. Blood samples were collected at pre-specified time points, and serum was analyzed for NL-201 concentration using a ligand-binding assay. Toxicokinetic parameters were determined using a non-compartmental model consistent with the IT and IV routes. Animals were sacrificed if tumor sizes reached 2000 mm3 or if body weight loss was >20%. In the bilateral tumor models, surviving tumor-free animals from both the IT and IV treatment arms were rechallenged with tumor cells after a washout period to assess antitumor immune responses.ResultsIT NL-201 demonstrated dose-dependent antitumor activity and was well tolerated based on a lack of clinical observations and body weight changes at doses up to 10 µg/mouse. Comparable antitumor activity was observed in mice receiving 3 μg/mouse NL-201 via IV or IT routes, but reduced systemic exposure and better tolerability were observed after IT administration. The estimated absolute bioavailability following 3 µg/mouse IT administration was 19.4%–66.5% of the NL-201 IV exposure. In the bilateral tumor model, IT NL-201 resulted in significant antitumor activity in both the treated and untreated tumors. Surviving animals from both IT and IV groups in which the initial tumors regressed rejected engraftment of the same tumor cell line upon rechallenge.ConclusionsIT NL-201 administration resulted in dose-dependent antitumor activity in both injected and uninjected tumors while demonstrating markedly reduced systemic exposure and improved tolerability compared to systemic administration at equivalent dose levels. Rechallenged animals failed to develop tumors, demonstrating durable tumor-specific immunity after IT NL-201 treatment. Results of this study support planned clinical investigation of IT NL-201 administration to increase NL-201 concentrations in accessible lesions.Ethics ApprovalThis study was approved by the Institutional Animal Care and Use Committee (IACUC) of CrownBio.

The LC-MS/MS-Based Measurement of Isopimaric Acid in Rat Plasma and Application of Pharmacokinetics

Isopimaric acid (IPA) exhibits a diverse array of pharmacological activities, having been shown to function as an antihypertensive, antitumor, antibacterial, and hypocholesterolemic agent. However, few studies of the pharmacokinetics of IPA have been performed to date, and such analyses are essential to explore the in vivo mechanisms governing the biological activity of this compound. As such, we herein designed a selective LC-MS approach capable of quantifying serum IPA levels in model rats using an Agilent HC-C18 column ( 250 mm × 4.6 mm , 5 μm) via isocratic elution with a mobile phase composed of methanol 0.5% formic acid (91 : 9, v/v) at a 1 mL/min flow rate. Ion monitoring at m/z 301.2 [M-H]- was used to quantify IPA levels in plasma samples from these rats, while internal standard (IS) levels were assessed at m/z 455.3 [M-H]-. After validation, this approach was employed to conduct a pharmacokinetic analysis of rats administered IPA via the oral (p.o. 50, 100, or 200 mg/kg) and intravenous (i.v. 5 mg/kg) routes. Analyses of noncompartmental pharmacokinetic parameters revealed that IPA underwent secondary absorption following oral administration to these animals, with the two tested oral doses (50 and 100 mg/kg) being associated with respective absolute bioavailability values of 11.9% and 17.5%. In summary, this study may provide a foundation for future efforts to explore the mechanistic basis for the pharmacological activity of IPA, offering insights to guide its subsequent clinical utilization.

Enhancement of dissolution profile of poorly aqueous soluble atorvastatin calcium by binary and ternary solid dispersion techniques

Atorvastatin calcium (ATV) is an HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibitor commonly known as a cholesterol-lowering agent. As a poorly water-soluble drug its absolute bioavailability is very low. To increase the water solubility as well as oral bioavailability, different hydrophilic carriers were used in different ratios (1:0.5, 1:1 and 1:2) to prepare reproducible binary and ternary solid dispersion formulations of ATV by simple physical mixing (PM) and fusion or melting technique. In vitro dissolution studies results revealed that in all cases, the cumulative percent drug release from ATV ternary SD formulations were greater than binary formulations, some marketed products and pure ATV powder. The order of the carriers in enhancing the drug release was found as kollidon 90F > pregelatinized starch > lutrol> kollidon 12F (99.1%, 98.8%, 96% and 95% respectively) for ternary SD formulations whereas pure ATV powder and marketed products showed cumulative percentage release 70.8%, 68.9% (B1) and 73.1% (B2), respectively. The best-out performed ternary SD formulation ATV:Kollidon 90 F (1:2) were further characterized using FT-IR and SEM. SEM analyses indicated conversion of crystal drug to amorphous form and FT-IR data suggested that little or no interaction between the drug and polymer. Bangladesh J. Sci. Ind. Res.56(3), 165-176, 2021

An in vivo pharmacokinetic study of metformin microparticles as an oral sustained release formulation in rabbits

Background Metformin hydrochloride is a biguanide derivative that has been widely used to treat type 2 diabetes in humans. In veterinary medicine, metformin has shown increasing potential for diabetes treatment in different species, such as equids, dogs, cats and rabbits. It is highly hydrophilic, with incomplete gastrointestinal absorption and very large variability in absolute bioavailability between species, ranging from 4% in equids to 60% in humans. Metformin also shows a short half-life of approximately 2 h in dogs, cats, horses and humans. The objectives of this study were to evaluate a poly (lactic acid) (PLA) metformin microparticle formulation to test in rabbits and conduct a pharmacokinetics study of intravenous (SIV) and oral solution (SPO) metformin administration and oral PLA microparticle (SPLA) administration to rabbits to evaluate the improvement in the metformin pharmacokinetics profile. Results Metformin-loaded PLA microparticles were characterized by a spherical shape and high encapsulation efficiency. The results from Fourier transform infrared (FTIR) spectroscopy suggested the presence of interactions between metformin and PLA. X-Ray diffraction (XRD) analysis corroborated the results from the differential scanning calorimetry (DSC) studies, showing that metformin is present in an amorphous state within the microparticles. Physicochemical characterization suggested that PLA and metformin hydrochloride interacted within the microparticles via hydrogen bonding interactions. The pharmacokinetic study in rabbits showed sustained-release characteristics from the prepared microparticles with a delay in the time needed to reach the maximum concentration (Tmax), decreased Cmax and bioavailability, and increased mean residence time (MRT) and half-life compared to the pure drug solution. Conclusions Metformin-loaded PLA microparticles showed optimal and beneficial properties in terms of their physicochemical characteristics, making them suitable for use in an in vivo pharmacokinetic study. The pharmacokinetic parameters of the metformin microparticles from the in vivo study showed a shorter Tmax, longer MRT and half-life, decreased Cmax and the prolonged/sustained release expected for metformin. However, the unexpected decrease in bioavailability of metformin from the microparticles with respect to the oral solution should be evaluated for microparticle and dose design in future works, especially before being tested in other animal species in veterinary medicine.