Preparation and comparison of tacrolimus-loaded solid dispersion and self-microemulsifying drug delivery system by in vitro/in vivo evaluation

An overview of oral bioavailability enhancement through self-emulsifying drug delivery systems

INTRODUCTION

The pharmaceutical technologists face a lot of challenges and limitations when designing novel drug delivery systems such as low oral bioavailability of many drugs, primarily due to poor solubility, slow dissolution rates, limited permeability through gastrointestinal mucosa, and rapid degradation within the body.

AREAS COVERED

The biopharmaceutical classification (BCS) classification represents a map in drug delivery research. Numerous active ingredients are characterized by low bioavailability due to poor water solubility, especially active ingredients of BCS class II and IV. Self-emulsifying drug delivery systems (SEDDS) could act as game changer in order to overcome the challenges and limitations of poor bioavailability. In this review, timelines representing the launch of self-emulsifying drug delivery systems, their introduction to the pharmaceutical platform and their benefits will be discussed in detail.

EXPERT OPINION

The development of multifunctional systems capable of combining controlled release, targeted delivery, and diagnostic capabilities is a promising avenue. As the technology matures, self-microemulsifying drug delivery systems and self-nanoemulsifying drug delivery systems are likely to become a standard approach for delivering BCS class II and IV drugs, transforming the pharmaceutical landscape.

Development of Solidified Self-microemulsifying Delivery Systems Containing Tacrolimus for Enhanced Dissolution and Pharmacokinetic Profile

The use of tacrolimus (FK506) as an immunosuppressant is limited by its low aqueous solubility and bioavailability. The self-microemulsifying drug delivery system (SMEDDS) has successfully improved the solubility of FK506 in our previous study. This study focused on the solidification of liquid SMEDDS to capture the benefits of both liquid SMEDDS and solid dosage forms. Among several porous silica adsorbents evaluated, Aeroperl® 300 Pharma showed the best performance in terms of droplet size, in vitro dissolution, adsorbent-drug compatibility, and tabletabilities. And precoating the adsorbent with polyvinylpyrrolidone K30 resulted in complete drug release. Hydroxypropyl methylcellulose based matrix tablet was developed to achieve a sustained release of FK506. Differential scanning calorimetry and X-ray powder diffraction indicated that FK506 was present in a molecular or amorphous state in the solidified SMEDDS and tablets. In vivo pharmacokinetic studies showed that the self-prepared tablet had improved bioavailability (179.02%) compared to the marketed product Advagraf®. This study provided a promising candidate with improved dissolution and bioavailability for FK506 and a prospective platform for SMEDDS development.

Tacrolimus-loaded chitosan-based nanoparticles as an efficient topical therapeutic for the effective treatment of atopic dermatitis symptoms

Atopic dermatitis (AD) is a chronic cutaneous disease with a complex underlying mechanism, and it cannot be completely cured. Thus, most treatment strategies for AD aim at relieving the symptoms. Although corticosteroids are topically applied to alleviate AD, adverse side effects frequently lead to the withdrawal of AD therapy. Tacrolimus (TAC), a calcineurin inhibitor, has been used to treat AD, but its high molecular weight and insolubility in water hinder its skin permeability. Herein, we developed and optimized TAC-loaded chitosan-based nanoparticles (TAC@CNPs) to improve the skin permeability of TAC by breaking the tight junctions in the skin. The prepared nanoparticles were highly loadable and efficient and exhibited appropriate characteristics for percutaneous drug delivery. TAC@CNP was stable for 4 weeks under physiological conditions. CNP released TAC in a controlled manner, with enhanced skin penetration observed. In vitro experiments showed that CNP was non-toxic to keratinocyte (HaCaT) cells, and TAC@CNP dispersed in an aqueous solution was as anti-proliferative as TAC solubilized in a good organic solvent. Importantly, an in vivo AD mouse model revealed that topical TAC@CNP containing ~1/10 of the dose of TAC found in commercially used Protopic® Ointment exhibited similar anti-inflammatory activity to that of the commercial product. TAC@CNP represents a potential therapeutic strategy for the management of AD.

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.

Omega-3 fatty acid-based self-microemulsifying drug delivery system (SMEDDS) of pioglitazone: Optimization, in vitro and in vivo studies

Pioglitazone (PGL) is an effective insulin sensitizer, however, side effects such as accumulation of subcutaneous fat, edema, and weight gain as well as poor oral bioavailability limit its therapeutic potential for oral delivery. Recent studies have shown that combination of both, PGL and fish oil significantly reduce fasting plasma glucose, improve insulin resistance, and mitigate pioglitazone-induced subcutaneous fat accumulation and weight gain. Nevertheless, developing an effective oral drug delivery system for administration of both medications have not been explored yet. Thus, this study aimed to develop a self-micro emulsifying drug delivery system (SMEDDS) for the simultaneous oral administration of PGL and fish oil. SMEDDS was developed using concentrated fish oil,Tween® 80, and Transcutol HP and optimized by central composite design (CCD). The reconstituted, optimized PGL-SMEDDS exhibited a globule size of 142 nm, a PDI of 0.232, and a zeta potential of -20.9 mV. The in-vitro drug release study of the PGL-SMEDDS showed a first-order model kinetic release and demonstrated remarkable 15-fold enhancement compared to PGL suspension. Additionally, following oral administration in fasting albino Wistar rats, PGL-SMEDDS exhibited 3.4-fold and 1.4-fold enhancements in the AUC0-24h compared to PGL suspension and PGL marketed product. The accelerated stability testing showed that the optimized SMEDDS formulation was stable over a three-month storage period. Taken together, our findings demonstrate that the developed fish oil-based SMEDDS for PGL could serve as effective nanoplatforms for the oral delivery of PGL, warranting future studies to explore its synergistic therapeutic potential in rats.

Cinnamon oil solid self-microemulsion mediates chronic mild stress-induced depression in mice by modulating monoamine neurotransmitters, corticosterone, inflammation cytokines, and intestinal flora

Cinnamon oil (CO) is a classic Chinese medicine with excellent soothing effects on exhaustion, weakness and depression. Cinnamaldehyde is the main active ingredient of cinnamic oil. Although CO have antidepression-like effects, limited information is available. Furthermore, the disadvantages of CO, such as low oral availability and difficult portability, limit its development. In this study, a Cinnamon Oil Solid Self-Microemulsifying Drug Delivery System (CO-S-SME) was designed, prepared. In addition, we explored the effects and mechanisms of CO-S-SME on chronic unpredictable mild stress (CUMS)-induced depression-like behavior, monoamine neurotransmitters, inflammatory factors, intestinal flora in mice. Mice were subjected CUMS to establish the depression model. The antidepressant effect of CO-S-SME was evaluated by behavioral tests. In addition, the expression levels of neurotransmitters, corticosterone (CORT) and inflammatory factors in CUMS mice were analyzed by enzyme-linked immunosorbent assay. In addition, we explored the effects of CO-S-SME on the diversity and richness of intestinal flora of mice in each group. Behavioral tests showed that CO-S-SME could effectively improve depression-like behaviors in CUMS mice. Specifically, CO-S-SME treatment effectively increased neurotransmitter levels and reduced the expressions of corticosterone and inflammatory factors in CUMS mice. CO-S-SME also changed the intestinal flora composition, decreased the ratio of Firmicutes to Bacteroidetes, reduced relative abundances of Lactobacillus, modulated Alpha diversity and beta diversity. These results suggest that CO-S-SME an act as a good antidepressant, exhibiting effects via monoamine neurotransmitters, CORT, inflammation cytokines, and intestinal flora.

Redox-Responsive Hyaluronic Acid-Tacrolimus Conjugate: Synthesis, Characterization, and In Vitro Immunosuppressive Activity

A redox-responsive macromolecular prodrug of tacrolimus, HA-ss-Tac, was constructed by conjugation of tacrolimus (TAC, FK506) through its succinate ester to cystamine-modified hyaluronic acid (HA-Cys), and its physicochemical properties and immunosuppressive activity were studied. The synthesized HA-ss-TAC was determined to contain 8% of chemically loaded TAC with significantly enhanced water solubility. The release study showed a sustained release of drug through slow degradation of linker-drug bonds. In vitro inhibition of proliferation of T- and B-lymphocytes was almost comparable to that of TAC, implying that the biologically active compound could be released from the conjugate. The polymeric prodrug lacks obvious cytotoxicity on Raw 264.7 macrophages and significantly suppressed the production of inflammatory cytokines IL-2 and IL-1β by LPS-activated cells. Additionally, the cellular uptake study of the FITC-labeled conjugate confirmed the HA receptor-mediated internalization of the conjugate into targeted cells, thus avoiding systemic side effects. Taken together, the HA-ss-TAC prodrug could be an optimal prodrug for intravenous administration based on this preliminary data and can be expected to have improved therapeutic efficacy.

Design, Characterization, and Evaluation of Diosmetin-Loaded Solid Self-microemulsifying Drug Delivery System Prepared by Electrospray for Improved Bioavailability

Diosmetin (DIOS) is a functional compound with poor water solubility, bad permeability, and crystal form. Self-microemulsifying drug delivery system (SMEDDS) was an effective formulation to overcome these shortcomings. In this study, liquid SMEDDS was prepared using Capmul® MCM C8 EP/NF, Cremophor EL, and PEG 400 (2:5.6:2.4, w/w/w) as excipients. Then, the novel technology of electrospray solidified liquid SMEDDS and prepared solid SMEDDS for inhibiting crystallization. Polyvinyl pyrrolidone (PVP) was used as carrier to construct DIOS-loaded solid SMEDDS, with polyethylene oxide (PEO) contributing to the formation of regular sphere in the process of spinning. The particle size of solid SMEDDS (194 ± 5 nm) was much bigger than of liquid SMEDDS (25 ± 1 nm), while DIOS-loaded solid SMEDDS showed greater dissolution rates in pH 1.2 and pH 6.8 media through in vitro drug release study. The solid nanoparticles were smooth and uniform from the graph of a scanning electron microscope (SEM). The graph of a transmission electron microscope (TEM) showed that small droplets were loaded in the matrix. Furthermore, DIOS was encapsulated by matrix in amorphous state via differential scanning calorimetry (DSC) and attenuated total reflection Fourier transform infrared (ATR-FTIR). The crystalline of DIOS was not formed in solid SMEDDS due to the characteristic peaks of DIOS disappeared in X-ray diffraction (XRD) pattern. Therefore, the oral bioavailability of DIOS improved significantly compared with liquid SMEDDS (4.27-fold). Hence, solid SMEDDS could improve the solubility and bioavailability of DIOS, through transfer of the state of crystalline to amorphous by electrospray technology.

Oral delivery of therapeutic peptides and proteins: Technology landscape of lipid-based nanocarriers

The oral administration of therapeutic peptides and proteins is favoured from a patient and commercial point of view. In order to reach the systemic circulation after oral administration, these drugs have to overcome numerous barriers including the enzymatic, sulfhydryl, mucus and epithelial barrier. The development of oral formulations for therapeutic peptides and proteins is therefore necessary. Among the most promising formulation approaches are lipid-based nanocarriers such as oil-in-water nanoemulsions, self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), liposomes and micelles. As the lipophilic character of therapeutic peptides and proteins can be tremendously increased such as by the formation of hydrophobic ion pairs (HIP) with hydrophobic counter ions, they can be incorporated in the lipophilic phase of these carriers. Since gastrointestinal (GI) peptidases as well as sulfhydryl compounds such as glutathione and dietary proteins are too hydrophilic to enter the lipophilic phase of these carriers, the incorporated therapeutic peptide or protein is protected towards enzymatic degradation as well as unintended thiol/disulfide exchange reactions. Stability of lipid-based nanocarriers towards lipases can be provided by the use to excipients that are not or just poorly degraded by these enzymes. Nanocarriers with a size <200 nm and a mucoinert surface such as PEG or zwitterionic surfaces exhibit high mucus permeating properties. Having reached the underlying absorption membrane, lipid-based nanocarriers enable paracellular and lymphatic drug uptake, induce endocytosis and transcytosis or simply fuse with the cell membrane releasing their payload into the systemic circulation. Numerous in vivo studies provide evidence for the potential of these delivery systems. Within this review we provide an overview about the different barriers for oral peptide and protein delivery, highlight the progress made on lipid-based nanocarriers in order to overcome them and discuss strengths and weaknesses of these delivery systems in comparison to other technologies.

Development and in vitro and in vivo evaluations of a microemulsion formulation for the oral delivery of oxaprozin

BACKGROUND

Oxaprozin is labeled as a Class II drug in the biopharmaceutical classification system, and its poor solubility in the entire gastrointestinal tract may be the main reason for its poor oral absorption capacity.

OBJECTIVE

The purpose of this study was to develop an oxaprozin formulation to enhance its oral absorption.

METHOD

Oxaprozin-loaded microemulsions were prepared using the titration method and pseudoternary phase diagram. Characterization experiments were performed on microemulsion preparations, including pH, particle size, shape, zeta potential and stability (thermodynamic, dilution, and differential scanning calorimetry). Then, the in vitro release of the microemulsion and in vivo pharmacokinetics in rats were evaluated.

RESULTS

Several microemulsion formulations were prepared. The optimal formulation was 15% oleoyl macrogolglycerides, 35% Tween 20/isopropanol (Km=2) and 50% distilled water. Its particle size met the requirements, and it had a spherical shape with a negatively charged surface. This microemulsion-loaded drug was applied to in vitro release and in vivo pharmacokinetic experiments at 7.47 mg/mL. In vitro release of the oxaprozin-loaded microemulsion best fit the first-order model, while the microemulsion preparation had a certain sustained release effect. In vivo pharmacokinetic experiments indicated that the microemulsion formulation significantly delayed the peak time of the blood concentration and simultaneously prolonged the half-life of drug elimination.

CONCLUSION

The obtained data revealed satisfactory results for this novel microemulsion of oxaprozin, which is very meaningful for clinical trials.

Preparation and evaluation of oral self-microemulsifying drug delivery system of Chlorophyll

OBJECTIVE

This study was aimed at improving the water solubility and oral bioavailability of Chl by self-microemulsifying drug delivery system (Chl-SMEDDS).

METHODS

Compatibility experiments, pseudo-ternary phase diagram and central composite design were used to optimize the formulation. The selected systems were further evaluated for physical characteristics, including particle size, zeta potential, and appearance. The stability, in vitro dispersion test, and in vivo intestinal perfusion experiments were used to evaluate the SMEDDS.

RESULTS

The optimal composition of Chl-SMEDDS included: Labrafil M 1944 CS (35%), kolliphor RH 40 (46%), Transcutol HP (19%) and 60 mg/g Chl. The appearance of water emulsified Chl-SMEDDS was green and transparent. The particle size, ζ-potential, and transmission electron microscopy studies showed that spherical globules of Chl-SMEDDS with a size of about 22.82 ± 1.29 nm and a negative surface charge of -24.21 ± 3.45 mV were obtained. Chl-SMEDDS could remain stable at 25 °C and 4 °C for at least 6 months. The dispersion test showed that Chl-SMEDDS dispersed spontaneously to form microemulsion after disintegration of capsule shell and 90% drug dispersed in just 30 min in pH 1.2 HCl without any drug precipitation during the test period. In vivo intestinal perfusion experiment revealed that the main absorption site for Chl-SMEDDS was duodenum.

CONCLUSIONS

This study indicates that SMEDDS formulation could be an effective strategy for the oral administration of Chl.

Improvement of Oral Bioavailability and Anti-Tumor Effect of Zingerone Self-Microemulsion Drug Delivery System

This study sought to prepare a self-microemulsion drug delivery system containing zingerone (Z-SMEDDS) to improve the low oral bioavailability of zingerone and anti-tumor effect. Z-SMEDDS was characterized by particle size, zeta potential and encapsulation efficiency, while its pharmacokinetics and anti-tumor effects were also evaluated. Z-SMEDDS had stable physicochemical properties, including average particle size of 17.29 ± 0.07 nm, the zeta potential of -22.81 ± 0.29 mV, and the encapsulation efficiency of 97.96% ± 0.02%. In vitro release studies have shown the release of zingerone released by Z-SMEDDS was significantly higher than free zingerone in different release media. The relative oral bioavailability of Z-SMEDDS was 7.63 times compared with free drug. Meanwhile, the half inhibitory concentration （IC50）of Z-SMEDDS and free zingerone was 8.45 μg/mL and 13.30 μg/mL, respectively on HepG2. This study may provide a preliminary basis for further clinical research and application of Z-SMEDDS.

Improved Oral Bioavailability and Hypolipidemic Effect of Syringic Acid via a Self-microemulsifying Drug Delivery System

This study aimed to develop a self-microemulsifying drug delivery system (SMEDDS) to enhance the solubility, oral bioavailability, and hypolipidemic effects of syringic acid (SA), a bioactive and poorly-soluble polyphenol. Based on the response surface methodology-central composite design (RSM-CCD), an optimum formulation of SA-SMEDDS, consisting of ethyl oleate (oil, 12.30%), Cremophor-EL (surfactant, 66.25%), 1,2-propanediol (cosurfactant, 21.44%), and drug loading (50 mg/g), was obtained. The droplets of SA-SMEDDS were nanosized (16.38 ± 0.12 nm), spherically shaped, and homogeneously distributed (PDI = 0.058 ± 0.013) nanoparticles with high encapsulation efficiency (98.04 ± 1.39%) and stability. In vitro release study demonstrated a prolonged and controlled release of SA from SMEDDS. In vitro cell studies signified that SA-SMEDDS droplets substantially promoted cellular internalization. In comparison with the SA suspension, SA-SMEDDS showed significant prolonged T_max, t_1/2, and MRT after oral administration. Also, SA-SMEDDS exhibited a delayed in vivo elimination, increased bioavailability (2.1-fold), and enhanced liver accumulation. Furthermore, SA-SMEDDS demonstrated significant improvement in alleviating serum lipid profiles and hepatic steatosis in high-fat diet-induced hyperlipidemia in mice. Collectively, SMEDDS demonstrated potential as a nanosystem for the oral delivery of SA with enhanced bioavailability and hypolipidemic effects.

3D printed tacrolimus suppositories for the treatment of ulcerative colitis

Ulcerative colitis is a global health problem, affecting millions of individuals worldwide. As an inflammatory condition localised in the large intestine, rectal delivery of immunosuppressive therapies such as tacrolimus is a promising strategy to maximise drug concentration at the site of action whilst minimising systemic side effects. Here, for the first time, self-supporting 3D-printed tacrolimus suppositories were prepared without the aid of moulds using a pharmaceutical semi-solid extrusion (SSE) 3D printer. The suppositories were printed vertically in three different sizes using combinations of two lipid pharmaceutical excipients (Gelucire 44/14 or Gelucire 48/16) and coconut oil. Although both suppository formulations had the appropriate viscosity characteristics for printing, the Gel 44 formulation required less energy and force for extrusion compared to the Gel 48 system. The Gel 44 disintegrated more rapidly but released tacrolimus more slowly than the Gel 48 suppositories. Although the tacrolimus release profiles were significantly different, both suppository systems released more than 80% drug within 120 min. DSC and XRD analysis was inconclusive in determining the solid-state properties of the drug in the suppositories. In summary, this article reports on the fabrication of 3D printed self-supporting suppositories to deliver personalised doses of a narrow therapeutic index drug, with potential benefits for patients with ulcerative colitis.

Formulation and Pharmacokinetic Evaluation of Phosal Based Zaltoprofen Solid Self-Nanoemulsifying Drug Delivery System

Abstract:

Background: Phosal based excipients are liquid concentrates containing phospholipids. They are used to solubilize water-insoluble drug and also act as an emulsifier to get the smallest droplet size of the formed emulsion after administration.

Objective:

The aim is to prepare phosal based self nanoemulsifying drug delivery system (SNEDDS) for water insoluble drug zaltoprofen.

Methods:

The various parameters like solubility of drug in different vehicles, ternary phase diagram are considered to formulate the stable emulsion which is further characterized by Self emulsification time and globule size analysis to optimize liquid SNEDDS of Zaltoprofen. Optimized L-SNEDDS was converted into free-flowing powder Solid-SNEDDS (S-SNEDDS). S-SNEDDS was evaluated for Globule size analysis after reconstitution, in vitro dissolution study and in vivo pharmacokinetic study in rats.

Results:

Phosal 53 MCT with highest drug solubility was used as oil along with Tween 80 and PEG 400 as surfactant and cosurfactant respectively to prepare liquid SNEDDS. Neusilin us2 was used as an adsorbent to get free-flowing S-SNEDDS. S-SNEDDS showed improved dissolution profile of the drug as compared to pure drug. In vivo study demonstrated that there is a significant increase in Cmax and AUC of S-SNEDDS compared to zaltoprofen powder.

Conclusion:

Phosal based SNEDDS formation can be successfully used to improve the dissolution and oral bioavailability of poorly soluble drug zaltoprofen.

Solid dispersion technology as a strategy to improve the bioavailability of poorly soluble drugs

Over the last half-century, solid dispersions (SDs) have been intensively investigated as a strategy to improve drugs solubility and dissolution rate, enhancing oral bioavailability. In this review, an overview of the state of the art of SDs technology is presented, focusing on their classification, the main preparation methods, the limitations associated with their instability, and the marketed products. To fully take advantage of SDs potential, an improvement in their physical stability and the ability to prolong the supersaturation of the drug in gastrointestinal fluids is required, as well as a better scientific understanding of scale-up for defining a robust manufacturing process. Taking these limitations into account will contribute to increase the number of marketed pharmaceutical products based on SD technology.

Effect of Carrier Lipophilicity and Preparation Method on the Properties of Andrographolide⁻Solid Dispersion

Solid dispersion (SD) is a useful approach to improve the dissolution rate and bioavailability of poorly water-soluble drugs. This work investigated the effects of carrier material lipophilicity and preparation method on the properties of andrographolide (AG)–SD. The SDs of AG and the carrier materials, polyethylene glycol (PEG) and PEG grafted with carbon chains of different length (grafted PEG), have been prepared by spray-drying and vacuum-drying methods. In AG–SDs prepared by the different preparation methods with the same polymer as carrier material, the intermolecular interaction, 5% weight-loss temperature, the melting temperature (T_m), surface morphology, crystallinity, and dissolution behavior have significant differences. In the AG–SDs prepared by the same spray-drying method with different grafted PEG as carrier material, T_m, surface morphology, crystallinity, and dissolution behavior had little difference. In the AG–SDs prepared by the same vacuum-drying method with different grafted PEG as carrier material, the crystallinity and T_m decreased, and the dissolution rate of AG increased with the increase of grafted PEG lipophilicity. The preparation method has an important effect on the properties of SD. The increase of carrier material lipophilicity is beneficial to the thermal stability of SD, the decrease of crystallinity and the increase of dissolution rate of a poorly water-soluble drug in the SD.

Enhanced Oral Bioavailability of Chlormadinone Acetate through a Self-Microemulsifying Drug Delivery System for a Potential Dose Reduction

Chlormadinone acetate (CMA) is a derivative of the naturally secreted hormone progesterone and exhibits reliable contraceptive and non-contraceptive benefits. Although the marketed product of CMA as oral tablets under the trade name Belara® has been highly successful, there is still room for further improvements in oral bioavailability and a reduction in the clinical dose to decrease related adverse effects. In the current study, a CMA-based self-microemulsifying drug delivery system (SMEDDS) was developed using 32% ethyl oleate as an oil phase, 40% Tween-80 as a surfactant, and 12% Transcutol P combined with 16% PEG400 as a cosurfactant, resulting in spherical droplets with a z-average particle size of 38.92 nm and an average zeta potential of - 3.18 mv. The in vitro release rate of CMA from CMA-SMEDDS in different media (distilled water, HCl solution at pH 1.2, phosphate buffers at pH 4.5 and pH 6.8) was significantly faster than that from Belara® in the first 15 min. A pharmacokinetic study in rats showed that the C_max and AUC of CMA-SMEDDS were significantly higher (P < 0.01) than those of Belara®, with a 1.98-fold increase in oral bioavailability. In comparison with Belara®, the developed CMA-SMEDDS showed promising release profiles both in vitro and in vivo, which could potentially be useful in enhancing oral bioavailability and reducing the clinical dose of CMA.

Different types, applications and limits of enabling excipients of pharmaceutical dosage forms

Along with the development of novel drug delivery systems the material science is also advancing. Conventional and novel synthetic or natural excipients provide opportunities to design dosage forms of the required features including their bioavailability. Emerging trends in the design and development of drug products indicate an increasing need for the functionality-related characterization of excipients. The purpose of this review is to provide an overview of different types of excipients in relation to their application possibilities in various dosage forms with special focus on the enabling excipients. The study also summarizes the applied excipient systems of research formulations and dosage forms available on the market.