Improved oral delivery of clonazepam through liquisolid powder compact formulations: In-vitro and ex-vivo characterization

In Vitro Release, Mucosal Permeation and Deposition of Cannabidiol from Liquisolid Systems: The Influence of Liquid Vehicles

This work investigated the influence of liquid vehicles on the release, mucosal permeation and deposition of cannabidiol (CBD) from liquisolid systems. Various vehicles, including EtOH, nonvolatile low- and semi-polar solvents, and liquid surfactants, were investigated. The CBD solution was converted into free-flowing powder using carrier (microcrystalline cellulose) and coating materials (colloidal silica). A physical mixture of the CBD and carrier–coating materials was prepared as a control. The non-crystalline state of CBD in the liquisolid systems was confirmed using XRD, FTIR and SEM studies. The CBD liquisolid powder prepared with volatile and nonvolatile solvents had a better CBD release performance than the CBD formed as the surfactant-based and control powders. The liquisolid systems provided the CBD permeation flux through porcine esophageal mucosa ranging from 0.68 ± 0.11 to 13.68 ± 0.74 µg·cm⁻²·h⁻¹, with the CBD deposition levels of 0.74 ± 0.04 to 2.62 ± 0.30 μg/mg for the dry mucosa. Diethylene glycol monoethyl ether showed significant CBD permeation enhancement (2.1 folds) without an increase in mucosal deposition, while the surfactants retarded the permeation (6.7–9.0 folds) and deposition (1.5–3.2 folds) significantly. In conclusion, besides the drug release, liquid vehicles significantly influence mucosal permeation and deposition, either enhanced or suppressed, in liquisolid systems. Special attention must be paid to the selection and screening of suitable liquid vehicles for liquisolid systems designed for transmucosal applications.

Technology of Processing Plant Extracts Using an Aluminometasilicate Porous Carrier into a Solid Dosage Form

A method of preparing tablets called liquisolid technique is currently emerging. In these formulations, an important role is played by porous carriers, which are the basic building blocks of liquisolid systems (LSSs). The most common are microcrystalline cellulose (MCC), magnesium aluminometasilicates, silica aerogels, mesoporous silicates, clays, etc. In this study, magnesium aluminometasilicate is used to prepare modified LSS formulations with plant extracts as model drugs dissolved in water (W) or ethanol (E). The modification involves drying tablets in a microwave (MW) and hot air dryer (HA) for a specified period. Powder blends and tablets were evaluated for physical properties, and their antioxidant activity (AA) was measured in a modified dissolution by ferric reducing antioxidant power assay (FRAP). PLS and ANOVA were used to compare tablets properties depending on the composition and technology. The experiment is based on a previous one, in which the plant extracts were processed into tablets using a similar method. Therefore, extending the study to include more plants and the robust statistical evaluation and comparison of the products was a procedure to justify the suitability of the presented method for a wide range of liquid plant extracts. As a result, we obtained tablets with excellent physical properties, including a short disintegration and dissolution, which is problematic in tableted extracts.

Development, Characterization, and Optimization of a Novel Abiraterone Acetate Formulation to Improve Biopharmaceutical Attributes Aided by Pharmacokinetic Modelling

Abiraterone acetate has very low bioavailability and drastic food effect to warrant a dosing regimen under fasting state only. Therefore, we aimed to develop and optimize a liquisolid compact formulation of abiraterone acetate to improve biopharmaceutical attributes aided by pharmacokinetic modelling and achieve dose reduction with no food effect on the formulation. Preliminary studies highlighted the importance of the selection of olive oil as a compatible vehicle. The pharmacokinetic model, integrated with gastrointestinal physiology, was used to predict fasted and fed state pharmacokinetic parameters. Optimization of the liquisolid formulation containing abiraterone acetate was carried at more than five times lower dose, i.e. 190 mg, compared to 1000 mg. A central composite design (CCD) was used to identify optimal levels of formulation factors, namely the amount of vehicle (olive oil), the amount of coating agent (silicon dioxide), and the amount of surfactant (polysorbate 80). Graphical optimization using the selected models in conjunction with maximization of the desirability was used to identify the optimized liquisolid formulation. The predicted pharmacokinetic parameters (fasted C_max 901.83 ng/mL, fasted AUC_inf 2723.82 ng·h/mL, fed C_max 1024.34 ng/mL, and fed AUC_inf 3041.83 ng·h/mL) of the optimized formulation were acceptable. Overall, the liquisolid compact formulation of abiraterone acetate was successfully developed and optimized. In vitro solubility and dissolution results aided by pharmacokinetic modelling also showed improved predicted bioavailability with greater than five times reduction in dose and elimination of food effect.

Clinical Pharmacokinetic Evaluation of Optimized Liquisolid Tablets as a Potential Therapy for Male Sexual Dysfunction

The study aimed at developing a liquisolid tablet (LST) containing tadalafil (TDL) and dapoxetine (DPX) with improved bioavailability as a potential therapy for male sexual dysfunction. A mixture of nonvolatile solvents, namely PEG 200 and Labrasol®, was utilized to prepare LSTs that were assessed for their quality characteristics. The Box–Behnken design (BBD) was employed to statistically explore the effect of the formulation factors on the quality attributes of LSTs. Furthermore, an in vivo pharmacokinetic study was carried out for the optimized LST in comparison with the marketed tablets on healthy human volunteers. The optimized LST revealed acceptable quality limits with enhanced dissolution for both APIs. The pharmacokinetic parameters after oral administration of the optimized LST indicated that the Cmax of TDL in LSTs was 122.61 ng/mL within 2h compared to the marketed tablets, which reached 91.72 ng/mL after 3 h, indicating the faster onset of action. The AUC was improved for TDL in LST (4484.953 vs. 2994.611 ng/mL∙h in the marketed tablet) and DPX in LST (919.633 vs. 794.699 ng/mL∙h in the marketed tablet). This enhancement in bioavailability potentially minimizes the associated side effects and improves the treatment of male sexual dysfunction, particularly for diabetic patients.

Enhancing the Hypolipidemic Effect of Simvastatin in Poloxamer-Induced Hyperlipidemic Rats via Liquisolid Approach: Pharmacokinetic and Pharmacodynamic Evaluation

This study aimed to enhance the dissolution of simvastatin (SMV) through its formulation in liquisolid tablets (LSTs) to improve its bioavailability and hypolipidemic activity after oral administration. SMV-LSTs were optimized using Box-Behnken design to maximize the rate and extent of SMV dissolution. The optimized SMV-LST was evaluated for pharmacokinetic parameters and potential hypolipidemic activity on induced hyperlipidemic rats. The dissolution parameters revealed a shortening of mean dissolution time from 10.99 to 6.82 min, increasing of dissolution rate during the first 10 min from 1253.15 to 1667.31 μg/min, and enhancing of dissolution efficiency after 60 min from 71.92 to 86.93% for SMV-LSTs versus the commercial SMV tablets. The obtained data reflected an improvement in the relative bioavailability of SMV with 148.232% which was confirmed by the significant reduction of the levels of circulating total cholesterol, triglycerides that reached the normal level after 12 h. In particular, the optimized SMV-LSTs reduced serum low-density lipoproteins (LDL) by 44.6% which was significantly different from the commercial SMV tablets. In contrast, the level of serum high-density lipoprotein (HDL) was significantly augmented after 4 h in rats treated with the optimized SMV-LSTs by 47.6%. Finally, the optimized SMV-LSTs showed a significant lower atherosclerotic index value which could maximize its potential in decreasing the risk of coronary disease and atherosclerosis. Overall enhancement in pharmacokinetics and pharmacodynamics in comparison with the commercial tablets confers the potential of the liquisolid approach as a promising alternative for improved oral bioavailability, hypolipidemic, and cardioprotective effects of SMV. Graphical abstract.

Benzodiazepines co-crystals screening using FTIR and Raman spectroscopy supported by differential scanning calorimetry

Co-crystals, which are defined as "solids that are crystalline materials composed of two or more molecules in the same crystal lattice" have recently been the focus of increased interest in the pharmaceutical industry since co-crystallization can improve unfavorable physicochemical properties of active pharmaceutical ingredients. Thus, the quest for new co-crystal screening methods has become an issue of importance. The aim of this work was, therefore, to show to what extent expanded methodology based on FTIR and Raman spectroscopy supported by the DSC method can be used as a reliable tool to screen co-crystallization. Because co-crystals of benzodiazepines had not yet been obtained, a set of 72 binary mixtures composed of eight 1,4-benzodiazepine derivatives and nine coformers were used as model substances. Potential co-crystals were prepared in solid-state by liquid-assisted grinding procedure. The characteristic FTIR and Raman bands which reflect hydrogen bond formation between benzodiazepine and coformer were used as proof of co-crystal creation. DSC was used as a supporting tool to reflect the phase transitions which occur during co-crystallization. As a result of the study, four potential co-crystals can be selected: lorazepam with nicotinamide, chlordiazepoxide with p-aminobenzoic and saccharin, and estazolam with fumaric acid. The detailed spectral and thermal characteristics of these systems are presented in this work. Thus, the proposed methodology of co-crystal screening based on FTIR and Raman data supported by the DSC examination of phase transitions facilitates the screening and detection of benzodiazepine co-crystal prepared by short time components ground with a slight additional volume of solvent.

Development and Characterization of Liquisolid Tablets Based on Mesoporous Clays or Silicas for Improving Glyburide Dissolution

The aim of this work was to evaluate the effectiveness of mesoporous clays or silicas to develop fast-dissolving glyburide tablets based on a liquisolid approach. Selected clay (Neusilin^®US2) and silica (Aeroperl^®300) allowed preparation of innovative drug liquisolid systems containing dimethylacetamide or 2-pyrrolidone as drug solvents, without using coating materials which are necessary in conventional systems. The obtained liquisolid powders were characterized for solid-state properties, flowability, compressibility, morphology, granulometry, and then used for directly compressed tablet preparation. The developed liquisolid tablets provided a marked drug dissolution increase, reaching 98% dissolved drug after 60 min, compared to 40% and 50% obtained from a reference tablet containing the plain drug, and a commercial tablet. The improved glyburide dissolution was attributed to its increased wetting properties and surface area, due to its amorphization/solubilization within the liquisolid matrix, as confirmed by DSC and PXRD studies. Mesoporous clay and silica, owing to their excellent adsorbent, flow, and compressibility properties, avoided use of coating materials and considerably improved liquid-loading capacity, reducing the carrier amount necessary to obtain freely flowing powders. Neusilin^®US2 showed a superior performance than Aeroperl^®300 in terms of the tablet’s technological properties. Finally, simplicity and cost-effectiveness of the proposed approach make it particularly advantageous for industrial scale-up.

Investigation of the effect of solubility increase at the main absorption site on bioavailability of BCS class II drug (risperidone) using liquisolid technique

BCS class II drugs usually suffer inadequate bioavailability as dissolution step is the absorption rate limiting step. In this work, the effect of solubility increase at the main absorption site for these drugs was investigated using risperidone as a drug model. Liquisolid technique was applied to prepare risperidone per-oral tablets of high dissolution rate at intestinal pH (6.8) using versatile nonionic surfactants of high solubilizing ability [Transcutol HP, Labrasol and Labrasol/Labrafil (1:1) mixture] as liquid vehicles at different drug concentrations (10-30%) and fixed (R). The prepared liquisolid tablets were fully evaluated and the dissolution rate at pH 6.8 was investigated. The formulae that showed significantly different release rate were selected and subjected to mathematical modeling using DE25, MDT and similarity factor (f2). Depending on mathematical modeling results, formula of higher dissolution rate was subjected to solid state characterization using differential scanning calorimetric (DSC), infrared spectroscopy (IR) and X-ray diffraction (XRD). Finally, the drug bioavailability was studied in comparison to conventional tablets in rabbits. Results showed that liquisolid tablet prepared using Labrasol/Labrafil (1:1) mixture as liquid vehicle containing 10% risperidone is a compatible formula with law drug crystallinity and higher dissolution rate (100% in 25 min). The drug bioavailability was significantly increased in comparison to the conventional tablets (1441.711 μg h/mL and 137.518 μg/mL in comparison to 321.011 μg h/mL and 38.673 μg/mL for AUC and Cpmax, respectively). This led to the conclusion that liquisolid technique was efficiently improved drug solubility and solubility increase of BCS class II drugs at their main absorption site significantly increases their bioavailability.

The Development of Self-nanoemulsifying Liquisolid Tablets to Improve the Dissolution of Simvastatin

The aim of this work was to develop self-nanoemulsifying liquisolid tablets (SNELT) to enhance the dissolution profile of poorly water-soluble simvastatin. SNELT present a unique technique of incorporating self-nanoemulsifying drug delivery systems (SNEDDS) into tablets. Optimized SNEDDS containing different oils, Cremophor^® RH 40 (surfactant) and Transcutol^® HP (co-surfactant), at different ratios, were used as liquid vehicles and loaded on carrier material, microcrystalline cellulose (MCC), and coating material, Cab-o-sil^® H-5 (nanosize colloidal silicon dioxide) powders at different loading factors (L _f ) and fixed excipient ratio (R = 20). The effect of using different carrier materials, granulated mannitol, crystalline mannitol, and maltodextrin with MCC at different ratios, and different coating materials, Aeroperl^® 300 (granulated silicon dioxide) at different excipient ratios (R), was also emphasized. Liquisolid powders with acceptable flowability, compressibility, and tablet weight were compressed into tablets. Results revealed that powders with L _f  = 0.2 possessed the most preferable properties to be tableted. SNELT with MCC and Cab-o-sil^® H-5 were able to generate nanoemulsions and to enhance the cumulative percent of drug dissolved at 60 min significantly to reach up to 90%. Furthermore, using carrier material (granulated mannitol/MCC at ratio 3:1) enabled SNELT to disperse into nanoemulsion (Z-average = 25.7 nm) and improved the dissolution profile significantly to reach 99% at 60 min. Cab-o-sil^® H-5 proved to be a better coating material compared to Aeroperl^® 300. In conclusion, developed SNELT were promising in enhancing in vitro dissolution of simvastatin and excipients highly affect SNELT's performance.

Liquisolid technique and its applications in pharmaceutics

Most of the newly developed drug candidates are lipophilic and poorly water-soluble. Enhancing the dissolution and bioavailability of these drugs is a major challenge for the pharmaceutical industry. Liquisolid technique, which is based on the conversion of the drug in liquid state into an apparently dry, non-adherent, free flowing and compressible powder, is a novel and advanced approach to tackle the issue. The objective of this article is to present an overview of liquisolid technique and summarize the progress of its applications in pharmaceutics. Low cost, simple processing and great potentials in industrial production are main advantages of this approach. In addition to the enhancement of dissolution rate of poorly water-soluble drugs, this technique is also a fairly new technique to effectively retard drug release. Furthermore, liquisolid technique has been investigated as a tool to minimize the effect of pH variation on drug release and as a promising alternative to conventional coating for the improvement of drug photostability in solid dosage forms. Overall, liquisolid technique is a newly developed and promising tool for enhancing drug dissolution and sustaining drug release, and its potential applications in pharmaceutics are still being broadened.

Effect of hydrogen bond formation/replacement on solubility characteristics, gastric permeation and pharmacokinetics of curcumin by application of powder solution technology

The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems (LS-1 to LS-12) were prepared using different vehicles (PEG 200, PEG 400 and Tween 80) and curcumin concentrations in vehicle (40%, 50%, 60% and 70%, w/w). The carrier [microcrystalline cellulose (MCC) PH102] to coat (Aerosil^®) ratio was 20 in all formulations. The systems were screened for pre-compression properties before being compressed to liquisolid tablets (LT-1 to LT-12). Post compression tests and in vitro dissolution of LTs were conducted and the results compared with those obtained for a directly compressed tablet (DCT) made of curcumin, MCC PH102 and Aerosil^®. LTs exhibited higher cumulative drug release (CDR) than the DCT and the optimum formulation, LT-9 (made using Tween 80), was studied by powder XRD, DSC, SEM and FTIR. Ex-vivo permeation of curcumin from LT-9 through goat gastrointestinal mucosa was significantly (P<0.05) enhanced and its oral bioavailability was increased 18.6-fold in New Zealand rabbits. In vitro cytotoxicity (IC₅₀) of LT-9 towards NCL 87 cancer cells was 40.2 µmol/L substantiating its anticancer efficacy. Accelerated stability studies revealed insignificant effects of temperature and humidity on LT-9. In summary, solubility enhancement of curcumin in LTs produced significant improvements in its permeation and bioavailability.

The effect of superdisintegrants on the properties and dissolution profiles of liquisolid tablets containing rosuvastatin

CONTEXT

The preparation of liquisolid systems (LSS) represents a promising method for enhancing a dissolution rate and bioavailability of poorly soluble drugs. The release of the drug from LSS tablets is affected by many factors, including the disintegration time.

OBJECTIVE

The evaluation of differences among LSS containing varying amounts and types of commercially used superdisintegrants (Kollidon® CL-F, Vivasol® and Explotab®).

MATERIALS AND METHODS

LSS were prepared by spraying rosuvastatin solution onto Neusilin® US2 and further processing into tablets. Varying amounts of superdisintegrants were used and the differences among LSS were evaluated. The multiple scatter plot method was used to visualize the relationships within the obtained data.

RESULTS AND DISCUSSION

All disintegrants do not showed negative effect on the flow properties of powder blends. The type and concentration of superdisintegrant had an impact on the disintegration time and dissolution profiles of tablets. Tablets with Explotab® showed the longest disintegration time and the smallest amount of released drug. Fastest disintegration and dissolution rate were observed in tablets containing Kollidon® CL-F (≥2.5% w/w). Also tablets with Vivasol® (2.5-4.0% w/w) showed fast disintegration and complete drug release.

CONCLUSION

Kollidon® CL-F and Vivasol® in concentration ≥2.5% are suitable superdisintegrants for LSS with enhanced release of drug.

A pH-triggered delayed-release chronotherapeutic drug delivery system of aceclofenac for effective management of early morning symptoms of rheumatoid arthritis

CONTEXT

Rheumatoid arthritis (RA) is differentiated as an early morning exacerbation of the core arthritis condition associated with increase in pain and stiffness in joints and necessitate for medication.

OBJECTIVE

The aim of the present work was to develop and optimise a pH-triggered delayed-release colon-specific aceclofenac microspheres and to accomplish chronotherapy of RA.

METHODS

A 3-factor, 3-level Box-Behnken design (BBD) was used to optimise selected variables. Developed formulation was evaluated for in vivo delayed response and anti-arthritis activity in rats.

RESULTS

The particle size and encapsulation efficacy of these microspheres were 117.36 ± 10.54 µm and 85.06 ± 5.85%, respectively. Optimised formulation was analysed by SEM, DSC, X-RPD and FTIR. The in vivo evaluation revealed delayed anti-inflammatory activity in carrageenan-induced rats and anti-arthritic activity in freund's adjuvant-induced arthritis rats.

CONCLUSION

The optimised aceclofenac microspheres formulation is potential for the chronotherapy of early morning symptoms of RA.

Effect of formulation variables on design, in vitro evaluation of valsartan SNEDDS and estimation of its antioxidant effect in adrenaline-induced acute myocardial infarction in rats

Valsartan is a specific angiotensin II antagonist used for the treatment of hypertension. It suffers from low aqueous solubility and high variability in its absorption after oral administration. The aim of this study was to improve the dissolution and thereby the bioavailability of Valsartan through the development of self nano-emulsifying drug delivery systems. Four ternary phase diagrams were constructed to identify the self-emulsification region of Capmul® MCM, Labrafil® M1944, Capryol™ 90 and Labrafac® PG together with Cremophore® RH 40 and Transcutol™ HP as oil, surfactant and co-surfactant, respectively. The effect of oil type, oil and surfactant concentration on droplet size and in vitro Valsartan dissolution were studied. The protective effect of the optimum formula F5 in adrenaline-induced oxidative stress in rats during myocardial infarction was determined. Formula F5 exhibited globule size of (13.95 nm) with 76.07% ± 1.10 of Valsartan dissolved after five minutes compared to Disartan 80 mg capsules (13.43%). Results revealed a significant reduction (p < 0.05) in serum aspartate transaminase, creatine kinase myocardial band and malondialdehyde levels, while a significant increase (p < 0.05) in serum glutathione in F5. Therefore, self nano-emulsifying drug delivery systems could be considered as a promising approach to improve the dissolution and thereby the bioavailability of Valsartan.

Modern evaluation of liquisolid systems with varying amounts of liquid phase prepared using two different methods

Liquisolid systems are an innovative dosage form used for enhancing dissolution rate and improving in vivo bioavailability of poorly soluble drugs. These formulations require specific evaluation methods for their quality assurance (e.g., evaluation of angle of slide, contact angle, or water absorption ratio). The presented study is focused on the preparation, modern in vitro testing, and evaluation of differences of liquisolid systems containing varying amounts of a drug in liquid state (polyethylene glycol 400 solution of rosuvastatin) in relation to an aluminometasilicate carrier (Neusilin US2). Liquisolid powders used for the formulation of final tablets were prepared using two different methods: simple blending and spraying of drug solution onto a carrier in fluid bed equipment. The obtained results imply that the amount of liquid phase in relation to carrier material had an effect on the hardness, friability, and disintegration of tablets, as well as their height. The use of spraying technique enhanced flow properties of the prepared mixtures, increased hardness values, decreased friability, and improved homogeneity of the final dosage form.