Assessment of Labrasol®/Labrafil®/Transcutol® (4/4/2, v/v/v) as a non-clinical vehicle for poorly water-soluble compounds after 4-week oral toxicity study in Wistar rats

Oral self-nanoemulsifying drug delivery systems for enhancing bioavailability and anticancer potential of fosfestrol: In vitro and in vivo characterization

PURPOSE

The objective of the current research work was to fabricate a fosfestrol (FST)-loaded self-nanoemulsifying drug delivery system (SNEDDS) to escalate the oral solubility and bioavailability and thereby the effectiveness of FST against prostate cancer.

METHODS

32 full factorial design was employed, and the effect of lipid and surfactant mixtures on percentage transmittance, time required for self-emulsification, and drug release were studied. The optimized solid FST-loaded SNEDDS (FSTNE) was characterized for in vitro anticancer activity and Caco-2 cell permeability, and in vivo pharmacokinetic parameters.

RESULTS

Using different ratios of surfactant and co-surfactant (Km) a pseudo ternary phase diagram was constructed. Thirteen liquid nano emulsion formulations (LNE-1 to LNE-13) were formulated at Km = 3:1. LNE-9 exhibited a higher % transmittance (99.25 ± 1.82 %) and a lower self-emulsification time (24 ± 0.32 s). No incompatibility was observed in FT-IR analysis. Within 20 min the solidified FST loaded LNE-9 (FSTNE) formulation showed almost complete drug release (98.20 ± 1.30 %) when compared to marketed formulation (40.36 ± 2.8 %), and pure FST (32 ± 3.3 %) in 0.1 N HCl. In pH 6.8 phosphate buffer, the release profiles are found moderately higher than in 0.1 N HCl. FSTNE significantly (P < 0.001) inhibited the PC-3 prostate cell proliferation and also caused apoptosis (P < 0.001) compared to FST. The in vitro Caco-2 cell permeability study results revealed 4.68-fold higher cell permeability of FSTNE than FST. Remarkably, 4.5-fold rise in bioavailability was observed after oral administration of FSTNE than plain FST.

CONCLUSIONS

FSTNE remarkably enhanced the in vitro anticancer activity and Caco-2 cell permeability, and in vivo bioavailability of FST. Thus, FST-SNEDDS could be utilized as a potential carrier for effective oral treatment of prostate cancer.

Formulation and Evaluation of a Self-Microemulsifying Drug Delivery System of Raloxifene with Improved Solubility and Oral Bioavailability

Poor aqueous solubility and dissolution limit the oral bioavailability of Biopharmaceutics Classification System (BCS) class II drugs. In this study, we aimed to improve the aqueous solubility and oral bioavailability of raloxifene hydrochloride (RLX), a BCS class II drug, using a self-microemulsifying drug delivery system (SMEDDS). Based on the solubilities of RLX, Capryol 90, Tween 80/Labrasol ALF, and polyethylene glycol 400 (PEG-400) were selected as the oil, surfactant mixture, and cosurfactant, respectively. Pseudo-ternary phase diagrams were constructed to determine the optimal composition (Capryol 90/Tween 80/Labrasol ALF/PEG-400 in 150/478.1/159.4/212.5 volume ratio) for RLX-SMEDDS with a small droplet size (147.1 nm) and stable microemulsification (PDI: 0.227). Differential scanning calorimetry and powder X-ray diffraction of lyophilized RLX-SMEDDS revealed the loss of crystallinity, suggesting a molecularly dissolved or amorphous state of RLX in the SMEDDS formulation. Moreover, RLX-SMEDDS exhibited significantly higher saturation solubility and dissolution rate in water, simulated gastric fluid (pH 1.2), and simulated intestinal fluid (pH 6.8) than RLX powder. Additionally, oral administration of RLX-SMEDDS to female rats resulted in 1.94- and 1.80-fold higher area under the curve and maximum plasma concentration, respectively, than the RLX dispersion. Collectively, our findings suggest SMEDDS is a promising oral formulation to enhance the therapeutic efficacy of RLX.

Synthesis of Methacryloylated Hydroxyethylcellulose and Development of Mucoadhesive Wafers for Buccal Drug Delivery

Non-ionic hydroxyethylcellulose (HEC) has limited mucoadhesive properties for application in transmucosal drug delivery. In this study, HEC was chemically modified by reaction with glycidyl methacrylate. This allowed introducing the methacryloyl groups to HEC structure to make it capable of forming covalent bonds with the sulfhydryl groups present in the mucin glycoprotein to achieve enhanced mucoadhesive properties. The results showed a successful modification of HEC as confirmed by ¹H NMR and FTIR spectroscopies. The quantification of methacryloyl moieties was conducted using HPLC. The toxicity studies using in vivo planaria acute toxicity assay, in vivo planaria fluorescent test, and in vitro MTT assay with Caco-2 cell line confirmed that the chemical modification of HEC does not result in any toxicological effects. Mucoadhesive wafers were developed based on parent and modified HEC as a model dosage form for buccal delivery. The mucoadhesive properties of modified HEC assessed using a tensile test were found to be significantly better compared to unmodified HEC.

Safety Assessment of PEGylated Alkyl Glycerides as Used in Cosmetics

The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 60 PEGylated alkyl glycerides. PEGylated alkyl glycerides are mono-, di-, and/or triglycerides that have been modified with ethylene glycol repeat units (in the starting material form as epoxide). Most of the PEGylated alkyl glycerides are reported to function as skin-conditioning agents or surfactants. The Panel reviewed the available animal and clinical data as well as data from the 1999 report for the 5 polyethylene glycol (PEG) glyceryl cocoates and the 2012 report of PEGylated oils, to determine the safety of these ingredients. The Panel concluded these ingredients are safe in the current practices of use and concentration when formulated to be nonirritating; this conclusion supersedes the 1999 conclusion issued on 5 PEG glyceryl cocoate ingredients.

Potent nonopioid antinociceptive activity of telocinobufagin in models of acute pain in mice

Introduction:

In recent decades, several researches have been conducted in search of new analgesics that do not present the side effects of opioids. In this context, animal venoms contain natural painkillers that have been used for the development of new analgesics.

Objective:

The aims of this study were to evaluate the antinociceptive effects of telocinobufagin (TCB), a bufadienolide isolated from Rhinella jimi venom, in murine acute pain models, and to verify the participation of the opioid system in these effects.

Methods:

TCB was purified from R. jimi venom by high-performance liquid chromatography, and its structure was confirmed by spectrometric techniques. TCB was administered intraperitoneally (i.p.) (0.062, 0.125, 0.25, 0.5, and 1 mg·kg⁻¹) and orally (p.o.) (0.625, 1.125, 2.5, 5, and 10 mg·kg⁻¹) in mice, which were then subjected to pain tests: acetic acid–induced writhing, formalin, tail-flick, and hot-plate. Involvement of the opioid system in TCB action was evaluated by naloxone i.p. injected (2.5 mg·kg⁻¹) 20 minutes before TCB administration. In addition, the TCB action on the μ, δ, and κ opioid receptors was performed by radioligand binding assays.

Results:

In all the tests used, TCB showed dose-dependent antinociceptive activity with more than 90% inhibition of the nociceptive responses at the doses of 1 mg·kg⁻¹ (i.p.) and 10 mg·kg⁻¹ (p.o.). Naloxone did not alter the effect of TCB. In addition, TCB did not act on the μ, δ, and κ opioid receptors.

Conclusion:

The results suggest that TCB may represent a novel potential nonopioid therapeutic analgesic for treatment of acute pains.

Formation of nanosuspensions in bottom-up approach: theories and optimization

BACKGROUND

Nanosuspensions, liquid dispersions with nanometer size distribution, are becoming trendy in pharmaceutical practice to formulate poorly water-soluble drugs and to enhance their bioavailability. Generally, nanosuspensions are produced in two main approaches; top-down or bottom-up. The former is based on size-reduction of large particles via milling or high pressure homogenization. The latter is focused on the mechanisms of nucleation and particle growth.

METHODS

In this review, the critical factors influencing the kinetics or dynamics of nucleation and growth are discussed. Subsequently, the mechanisms of nanosuspension instability as well as strategies for stabilization are elaborated. Furthermore, the effects of stabilizers on key parameters of instability as well as the process of choosing an appropriate stabilizer is discussed.

RESULTS

Steric and electrostatic stabilizations or combination of them is essential for nanosuspensions formulation to prevent coagulation. Accordingly, some characteristics of stabilizers play critical role on stability and optimization of nanosuspensions; i.e., HLB and concentration. Nevertheless, after reviewing various articles, it is ascertained that each formulation requires individual selection of surfactants according to the parameters of the particle surface and the medium.

CONCLUSIONS

Based on the results, application of excipients such as stabilizers requires proper optimization of type and concentration. This implies that each formulation requires its own optimization process. Graphical Abstract ᅟ.

Safety assessment of the pharmacological excipient, diethylene glycol monoethyl ether (DEGEE), using in vitro and in vivo systems

BACKGROUND

Diethylene glycol monoethyl ether (DEGEE) is widely used as a solubilizer in cosmetics as well as in oral, topical, transdermal and injectable pharmaceutical formulations. Due to the unavailability of detailed toxicological studies on DEGEE, the Scientific Committee on Consumer Products (SCCP) found its toxicological reports to be unsatisfactory, comprising only summaries. Also, a few reports have raised concern on the use of DEGEE as it might cause damage to the kidneys.

OBJECTIVE

Safety assessment of DEGEE using in vitro and in vivo models.

METHODS

In vitro effects of DEGEE (0.5-25 mg/ml) were assessed in the HEK293 human embryonic kidney cells. In vivo effects were evaluated after single acute exposure of DEGEE via intraperitoneal route in Swiss albino mice and further, a 28 days subchronic exposure study was conducted where DEGEE was administered orally, once daily.

RESULTS

DEGEE was cytotoxic to HEK293 cells, and an IC50 of 15 mg/ml was established. An increase in the intracellular levels of ROS and alteration in the mitochondrial membrane potential led to nuclear fragmentation and induction of apoptosis in these cells. Survival rate of animals administered intraperitoneally with a single acute dose of 1000 mg/kg DEGEE was 100% with no significant changes in the behavioural and histological parameters. However, the dose of 3000 mg/kg and above led to total mortality within 14 days of acute exposure. Subchronic oral exposure of 500-2000 mg/kg DEGEE showed no significant changes in the hematological, biochemical and histopathological parameters.

CONCLUSIONS

The in vitro findings indicate that the nephrotoxic potential of DEGEE cannot be ruled out. The results of the in vivo studies reveal that the degree of toxic effects shown by DEGEE varies, depending on the dose, duration of exposure and routes of administration. Therefore, the present findings are of relevance and thorough studies should be conducted before using this substance in clinical formulations. Graphical abstract Evaluation of the toxic potential of Diethylene glycol monoethyl ether.

Ravuconazole self-emulsifying delivery system: in vitro activity against Trypanosoma cruzi amastigotes and in vivo toxicity

Self-emulsifying drug delivery systems (SEDDSs) are lipid-based anhydrous formulations composed of an isotropic mixture of oil, surfactant, and cosurfactants usually presented in gelatin capsules. Ravuconazole (Biopharmaceutics Classification System [BCS] Class II) is a poorly water-soluble drug, and a SEDDS type IIIA was designed to deliver it in a predissolved state, improving dissolution in gastrointestinal fluids. After emulsification, the droplets had mean hydrodynamic diameters <250 nm, zeta potential values in the range of −45 mV to −57 mV, and showed no signs of ravuconazole precipitation. Asymmetric flow field-flow fractionation with dynamic and multiangle laser light scattering was used to characterize these formulations in terms of size distribution and homogeneity. The fractograms obtained at 37°C showed a polydisperse profile for all blank and ravuconazole–SEDDS formulations but no large aggregates. SEDDS increased ravuconazole in vitro dissolution extent and rate (20%) compared to free drug (3%) in 6 h. The in vivo toxicity of blank SEDDS comprising Labrasol^® surfactant in different concentrations and preliminary safety tests in repeated-dose oral administration (20 days) showed a dose-dependent Labrasol toxicity in healthy mice. Ravuconazole–SEDDS at low surfactant content (10%, v/v) in Trypanosoma cruzi-infected mice was safe during the 20-day treatment. The anti-T. cruzi activity of free ravuconazole, ravuconazole–SEDDS and each excipient were evaluated in vitro at equivalent ravuconazole concentrations needed to inhibit 50% or 90% (IC₅₀ and IC₉₀), respectively of the intracellular amastigote form of the parasite in a cardiomyocyte cell line. The results showed a clear improvement of the ravuconazole anti-T. cruzi activity when associated with SEDDS. Based on our results, the repurposing of ravuconazole in SEDDS dosage form is a strategy that deserves further in vivo investigation in preclinical studies for the treatment of human T. cruzi infections.

Effects of the Oral Oxytocin Receptor Antagonist Tocolytic OBE001 on Reproduction in Rats

BACKGROUND

OBE001 is a novel, orally active nonpeptide oxytocin receptor antagonist under development for the treatment of preterm labor and improvement in embryo implantation and pregnancy rate in assisted reproductive technology (ART). The reproductive safety of OBE001 was evaluated in customized fertility embryonic development (FER)/early embryonic development (EED) and fetal development (FD) and pre/postnatal development (PPN) studies mimicking clinical exposure scenarios.

METHODS

Oral OBE001 was evaluated at doses of 37.5, 75, and 125 mg/kg/d in female rats during a FER/EED study (from premating to implantation) and throughout FD during a FD/PPN study.

RESULTS

No OBE001 effects were observed during the FER/EED study. The FD/PPN study did not result in adverse OBE001 effects in females allowed to litter, their offspring, and second-generation fetuses. Females at 125 mg/kg/d who underwent cesarean section before term had slight reductions in body weights and food consumption, and associated fetuses had slightly delayed ossification of skull bones, which was not adverse in the absence of effects on live offspring.

CONCLUSION

OBE001 at up to 125 mg/kg/d had no effects on EED and no adverse effects on FD and postnatal development of rats. These results constitute an important step toward the development of OBE001 in preterm labor and ART indications.

Lower irritation microemulsion-based rotigotine gel: formulation optimization and in vitro and in vivo studies

BACKGROUND

Rotigotine is a potent and selective D1, D2, and D3 dopaminergic receptor agonist. Due to an extensive first-pass effect, it has a very low oral bioavailability (approximately 0.5% in rats).

PURPOSE

The present investigation aimed to develop a microemulsion-based hydrogel for transdermal rotigotine delivery with lower application site reactions.

METHODS

Pseudoternary phase diagrams were constructed to determine the region of oil in water (o/w)-type microemulsion. Central composite design was used to support the pseudoternary phase diagrams and to select homogeneous and stable microemulsions with an optimal amount of rotigotine permeation within 24 hours. In vitro skin permeation experiments were performed, using Franz diffusion cells, to compare rotigotine-loaded microemulsions with rotigotine solutions in oil. The optimized formulation was used to prepare a microemulsion-based hydrogel, which was subjected to bioavailability and skin irritancy studies.

RESULTS

The selected formulations of rotigotine-loaded microemulsions had enhanced flux and permeation coefficients compared with rotigotine in oil. The optimum microemulsion contained 68% water, 6.8% Labrafil(®), 13.44% Cremophor(®) RH40, 6.72% Labrasol(®), and 5.04% Transcutol(®) HP; the drug-loading rate was 2%. To form a microemulsion gel, 1% Carbomer 1342 was added to the microemulsion. The bioavailability of the rotigotine-loaded microemulsion gel was 105.76%±20.52% with respect to the marketed rotigotine patch (Neupro(®)). The microemulsion gel irritated the skin less than Neupro.

CONCLUSION

A rotigotine microemulsion-based hydrogel was successfully developed, and an optimal formulation for drug delivery was identified. This product could improve patient compliance and have broad marketability.

Chitosan based atorvastatin nanocrystals: effect of cationic charge on particle size, formulation stability, and in-vivo efficacy

Cationic charged chitosan as stabilizer was evaluated in preparation of nanocrystals using probe sonication method. The influence of cationic charge densities of chitosan (low CS_L, medium CS_M, high CS_H molecular weights) and Labrasol^® in solubility enhancement and modifying the release was investigated, using atorvastatin (ATR) as poorly soluble model drug. Compared to CS_M and CS_H; low cationic charge of CS_L acted as both electrostatic and steric stabilizer by significant size reduction to 394 nm with charge of 21.5 meV. Solubility of ATR-CS_L increased to 60-fold relative to pure ATR and ATR-L. Nanocrystals were characterized for physiochemical properties. Scanning electron microscopy revealed scaffold-like structures with high surface area. X-ray powder diffractometry and differential scanning calorimetry revealed crystalline to slight amorphous state changes after cationic charge size reduction. Fourier transform-infrared spectra indicated no potent drug-excipient interactions. The enhanced dissolution profile of ATR-CS_L indicates that sustained release was achieved compared with ATR-L and Lipitor^®. Anti-hyperlipidemic performance was pH dependent where ATR-CS_L exhibited 2.5-fold higher efficacy at pH 5 compared to pH 6 and Lipitor^®. Stability studies indicated marked changes in size and charge for ATR-L compared to ATR-CS_L exemplifying importance of the stabilizer. Therefore, nanocrystals developed with CS_L as a stabilizer is a promising choice to enhance dissolution, stability, and in-vivo efficacy of major Biopharmaceutical Classification System II/IV drugs.

Preclinical formulations: insight, strategies, and practical considerations

A lot of resources and efforts have been directed to synthesizing potentially useful new chemical entities (NCEs) by pharmaceutical scientists globally. Detailed physicochemical characterization of NCEs in an industrial setup begins almost simultaneously with preclinical testing. Most NCEs possess poor water solubility posing bioavailability issues during initial preclinical screening, sometimes resulting in dropping out of an NCE with promising therapeutic activity. Selection of right formulation approach for an NCE, based on its physicochemical properties, can aid in improving its solubility-related absorption and bioavailability issues. The review focuses on preclinical formulations stressing upon different preclinical formulation strategies and deciphers the understanding of formulation approaches that could be employed. It also provides detailed information related to a vast pool of excipients available today, which is of immense help in designing preclinical formulations. Few examples mentioned, throw light on key aspects of preclinical formulation development. The review will serve as an important guide for selecting the right strategy to improve bioavailability of NCEs for academic as well as industrial formulation scientists.

A review of the nonclinical safety of Transcutol®, a highly purified form of diethylene glycol monoethyl ether (DEGEE) used as a pharmaceutical excipient

Transcutol® (Diethylene glycol monoethyl ether, DEGEE), CAS # 111-90-0, is commonly used as a vehicle in the formulation or manufacturing process of pharmaceuticals, cosmetics, and food additives. This paper presents unpublished nonclinical safety data using a form of DEGEE which includes a significantly decreased level of impurities, specifically ethylene glycol and diethylene glycol. It also reviews the history of use, regulatory status, and previously published toxicity data for DEGEE. The review supports that DEGEE is well tolerated across animal species and gender with toxicity occurring only at levels well above those intended for human use. At high levels of exposure, the kidney is identified as the critical target organ of DEGEE toxicity. DEGEE is negative for genotoxicity in in vitro and in vivo studies. Subchronic and chronic toxicity studies produced no reports of preneoplastic changes in organs, but the animal data is insufficient to allow a definitive opinion as to carcinogenicity. In silico data suggested that DEGEE is not carcinogenic or genotoxic. Developmental toxicity was seen in rats but only at levels 200 times greater than the estimated oral Permissible Daily Exposure Level of 10 mg/kg/day. The nonclinical data along with the long history of DEGEE use as a vehicle and solvent by multiple routes provide evidence of its safety. Furthermore, the novel data discussed herein provides evidence that toxicity previously associated with high levels of DEGEE in nonclinical studies conducted prior to 1990 could possibly be attributed to the presence of significant amounts of ethylene glycol or other impurities.

Effects of spray-drying and choice of solid carriers on concentrations of Labrasol® and Transcutol® in solid self-microemulsifying drug delivery systems (SMEDDS)

Solid self-microemulsifying drug delivery systems (SMEDDS) have been used increasingly for improving the bioavailability of hydrophobic drugs. Labrasol^® and Transcutol^® are used widely as surfactant and solubilizer in the formulation of solid SMEDDS. We investigated the effects of spray-drying and the use of different solid carriers on concentrations of Labrasol^® and Transcutol^® in solid SMEDDS with scutellarin as the formulated drug. Liquid and gas chromatography tandem mass spectrometry (LC-MS and GC-MS) methods were developed for measuring low concentrations of Labrasol^® and Transcutol^®. In the preparation of solid SMEDDS, lactose, hydroxypropylmethyl cellulose (HPMC) and microcrystalline cellulose (MCC) were used as solid carriers. Judging from the retention ratios of Labrasol^® and Transcutol^®, the droplet size of solid SMEDDS increased after spray-drying of liquid SMEDDS, and concentrations of these excipients decreased after the solidifying procedure. In such reduction, Lactose and HPMC were found to preserve Labrasol^® and Transcutol^® better than MCC during spray-drying, and the resultant droplet sizes were smaller than that of MCC. Labrasol^® and Transcutol^® showed good thermal stability at 60 °C degree for 10 days. It can be concluded that spray-drying could increase the droplet size of solid SMEDDS and decreased the concentration of Labrasol^® and Transcutol^® therein, while water-soluble solid carriers could preserve Labrasol^® and Transcutol^® better than insoluble carriers in the solid SMEDDS.

Toxicity Profile of Solvents by Aspiration Approach for Topical Agent Delivery to Respiratory Tract Epithelium

Agent solubility is a problem for aspiration of agents into lungs for chemopreventive efficacy evaluation, since many agents have to be dissolved in solvents. These solvents may be toxic to the lung epithelium. A study was conducted in female A/J mice to determine toxicity of different solvent concentrations by using saline, dimethyl sulfoxide (DMSO), ethanol, polyethylene glycol 400 (PEG-400), and labrasol for 1, 5, and 28 days via aspiration route. Toxicity was determined by measuring changes in body weight and bronchoalveolar lavage fluid (BALF). No significant difference was observed in body weight, differential cell counts, lactate dehydrogenase (LDH) and total protein in all solvent groups compared to saline by 28 days except 50% ethanol. However, myeloperoxidase (MPO) and macrophage inflammatory protein-2 (MIP-2) showed significant increase in 2% and 10% DMSO, 10% ethanol, 0.1% and 2% PEG-400, and 1% labrasol by longer dosing. All solvents except for 10% ethanol and 2% PEG-400 are suitable for agent aspiration.

Effects of artemisinin and Artemisia extracts on Haemonchus contortus in gerbils (Meriones unguiculatus)

Haemonchus contortus is a blood-sucking abomasal parasite of small ruminants that is responsible for major losses to producers worldwide. Resistance of this nematode to commercial anthelmintics has produced a demand for alternative control methods. Plants in the genus Artemisia have traditionally been used as anthelmintics and whole plants and plant extracts have demonstrated activity against gastrointestinal nematodes in several studies. In addition, Artemisia annua is the sole commercial source of artemisinin, the raw material used to produce drugs effective against the hemoprotozoan malaria parasites (Plasmodium species). Artemisinin derivatives have also shown efficacy against some trematodes, including Fasciola hepatica and Schistosoma species. In this study, artemisinin was tested for efficacy against H. contortus in a gerbil model of infection. Also tested in the gerbil model were an aqueous extract, an ethanolic extract and the essential oil of A. annua, and an ethanolic extract of Artemisia absinthium. In all experiments, gerbils were infected with 600 third-stage H. contortus larvae. In experiment 1, gerbils were treated orally with 400 milligrams per kilogram body weight (mg/kg BW) artemisinin once or 200mg/kg BW artemisinin daily for 5 days (Days 4-8 post-infection). In experiment 2, gerbils were treated daily for 5 days with 600 mg/kg BW of A. annua ethanolic or aqueous extract. In Experiment 3, gerbils were treated with 1000 mg/kg BW of A. annua or A. absinthium ethanolic extract or with 300 mg/kg BW of A. annua essential oil daily for five consecutive days (Days 4-8 post-infection). No significant effects of treatment were seen with artemisinin or any of the Artemisia species extracts at the dosages studied. The non-ionic surfactant Labrosol(®) was an effective nontoxic solvent for delivery of hydrophilic plant extracts and the lipophilic essential oil used in the study.