Ball-milled solid dispersions of BCS Class IV drugs: Impact on the dissolution rate and intestinal permeability of acyclovir

Supersaturating drug delivery systems containing fixed-dose combination of two antihypertensive drugs: Formulation, in vitro evaluation and molecular metadynamics simulations

The purpose of this study was to associate the poorly water-soluble antihypertensive drugs candesartan cilexetil (CC) and hydrochlorothiazide (HCTZ) as fixed-dose combination, in the form of ternary Amorphous Solid Dispersions (ASD), using hydroxypropylmethylcellulose acetate succinate (HPMCAS) type M as polymeric carrier. The potential of the system to generate and to maintain supersaturation of both drugs was also evaluated. The ASDs were prepared by ball milling technique and solid-state characterization was performed by differential scanning calorimetry (DSC), Fourier transformed infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD). Interaction between drugs and polymer in solid-state was evaluated by molecular metadynamics simulations. In vitro supersaturation profiles were determined in biorelevant medium. Physicochemical stability of ASDs was also evaluated under different storage conditions. Amorphization of both drugs was confirmed by solid-state characterization techniques. Molecular metadynamics simulations indicated that CC has stronger interaction with HMPCAS than HCTZ. In vitro supersaturation studies have shown that ternary ASDs could generate and maintain supersaturation of both drugs in biorelevant medium. The polymer reduced the desupersaturation of both drugs. Ternary ASDs also showed physicochemical stability over a period of 90 days, demonstrating the potential of the polymer in reducing the drugs recrystallization over the time. Ternary ASDs of CC, HCTZ and HPMCAS can be considered a promising system to associate the drugs as fixed-dose combinations. Also, these systems generate and maintain supersaturation of both drugs in biorelevant medium, with great storage stability. HPMCAS M was a good carrier for reducing the desupersaturation of associated HCTZ and CC.

Influence of nutrients on the bioaccessibility and transepithelial transport of polybrominated diphenyl ethers measured using an in vitro method and Caco-2 cell monolayers

Previous research has shown the absorption of polybrominated diphenyl ethers (PBDEs) in the human gastrointestinal tract, but limited attention has been given to the influence of nutrients on PBDE absorption from food matrices. We investigated the effects of nutrients (oil, starch, protein, and dietary fiber) on the absorption and transport of PBDEs in a Caco-2 cell model and bioaccessibility of PBDEs by an in vitro gastrointestinal digestion method. The results showed that the accumulation ratios of PBDE congeners in Caco-2 cells were higher in the nutrient addition groups (oil: 26.7-50.6%, starch: 27.0-58.7%, protein: 12.1-44.1%, and dietary fiber: 28.2-55.1%) than the control group (7.17-36.1%), whereas the transport ratios were lower (oil: 2.30-7.20%, starch: 1.55-9.15%, protein: 1.04-8.78%, and dietary fiber: 0.85-7.04%) than control group (3.78-11.1%). Additionally, the PBDE bioaccessibility could be increased by adding the nutrients, particularly oil and starch. This study clarified the differences in PBDE absorption in the presence of nutrients using the in vitro digestion and Caco-2 cell model. The findings showed that nutrients were an important factor that promoted PBDE absorption in the gastrointestinal tract. Therefore, it is important to focus on a novel dietary strategy of food consumption with contaminant compounds to protect human health.

The use of amphiphilic copolymer in the solid dispersion formulation of nimodipine to inhibit drug crystallization in the release media: Combining nano-drug delivery system with solid preparations

Solid dispersion is a widely used method to improve the dissolution and oral bioavailability of water-insoluble drugs. However, due to the strong hydrophobicity, the drug crystallization in the release media after drug dissolution and the resulted decreased drug absorption retards the use of solid dispersions. It is widely known that the amphiphilic copolymer can encapsulate the hydrophobic compounds and help form stable nano-dispersions in water. Inspired by this, we tried to formulate the solid dispersion of nimodipine by using amphipathic copolymer as one of the carriers. Concerning the solid dispersions, there are many important points involved in these formulations, such as the miscibility between the drug and the carriers, the storage stability of solid dispersions, the dissolution enhancement and so on. In this study, a systemic method is proposed. In details, the supersaturation test and the glass transition temperature (T_g) measurement to predict the crystallization inhibition, the ratios of different components and the storage stability, the interactions among the components were investigated in detail by nuclear magnetic resonance (¹H NMR) and isothermal titration calorimetry (ITC) and, the final dissolution and oral bioavailability enhancement. It was found that the amphiphilic copolymer used in the solid dispersion encouraged the formation the drug loading micelles in the release media and, finally, the problem of drug crystallization in the dissolution process was successfully solved.

Solid dispersions of telaprevir with improved solubility prepared by co-milling: formulation, physicochemical characterization, and cytotoxicity evaluation

Telaprevir (TVR) is typically a poorly soluble drug with an extremely low bioavailability of 1.7%. Polymorph modifications cannot improve the solubility of TVR because it only has a single unsolvated crystalline form. Co-crystals also provide limited bioavailability enhancement for TVR. Thus, in this study, we increased the solubility and dissolution rate of TVR through formulations of TVR-polymer solid dispersions. Three solid dispersions of TVR were successfully prepared by co-milling with polyvinylpyrrolidone K30 (PVP), polyethylene glycol 6000, and hydroxypropyl methylcellulose (HPMC), which were characterized by different techniques. According to X-ray powder diffraction and differential scanning calorimetry results, TVR presented in amorphous form in all solid dispersions. The fourier transform infrared spectra results indicated that TVR may connect with polymers through the N-H···O or O-H···O hydrogen bonds, which were verified by molecular docking. TVR-PVP and TVR-HPMC displayed a good stability at conventional RH levels, and their thermostabilities were better than those of milled TVR. Among the three solid dispersions, TVR-HPMC showed significant solubility and dissolution rate advantages in different media. Moreover, TVR-HPMC displayed the same anticancer efficacy with crystalline TVR and presented no toxic side effects to normal liver cells. Thus, TVR-HPMC showed potential application value.

Atorvastatin calcium inclusion complexation with polysaccharide arabinogalactan and saponin disodium glycyrrhizate for increasing of solubility and bioavailability

The aim of the present investigation was to enhance the solubility and dissolution of atorvastatin calcium (ATV), a poorly water-soluble drug with larch polysaccharide arabinogalactan (AG) and disodium glycyrrhizate (Na₂GA) as carriers of drug delivery systems for improving its bioavailability. The interactions of ATV with AG or Na₂GA were investigated by DSC, XRD, SEM, and NMR techniques. The molecular weights of supramolecular systems-inclusion complexes and micelles-which are the hosts for ATV molecules were measured. On the other hand, the rapid storage assay (+ 40 °C for 3 months) showed that the chemical stability of ATV/AG and ATV/Na₂GA complexes had been enhanced compared with pure ATV. In vitro drug release showed a significant increase in ATV's dissolution rate after formation of a complex with Na₂GA or AG. Pharmacokinetic tests in vivo on laboratory animals showed a significant increase in ATV's bioavailability after its introduction as a complex with Na₂GA or AG. Moreover, ATV/AG and ATV/Na₂GA complexes showed a more prominent decrease of total cholesterol (TC) level compared to net ATV. Therefore, the novel mechanochemically synthesized complexes of ATV with AG or Na₂GA as drug delivery systems might be potential and promising candidates for hypercholesterolemia treatment and deserved further researches.

Composite Microparticles Based on Natural Mucoadhesive Polymers with Promising Structural Properties to Protect and Improve the Antifungal Activity of Miconazole Nitrate

Oropharyngeal candidiasis is a recurrent oral infection caused by Candida species. Gel formulation containing miconazole nitrate is the most common approach for treating oral candidiasis. However, traditional oral topical antifungal therapies have many limitations, including short contact time with the oral mucosa and the necessity to administrate various doses per day. Thus, the aim of this work was to formulate composited microparticulated systems based on combinations of mucoadhesive cationic, anionic, and nonionic polymers that could protect and modify the drug release rate and therefore avoid a fast dilution of the drug by saliva. Microparticulated systems were prepared by the spray drying method employing chitosan, gelatin, and hydroxypropyl methylcellulose. The morphology of the systems was investigated by scanning electron microscopy; drug crystallinity was studied by X-ray, while interactions between polymers were analyzed by infrared spectroscopy. Drug release and halo zone test were employed to analyze the release and activity of the systems loaded with miconazole against Candida albicans cultures. The most appropriate microparticulated system was the one based on chitosan and gelatin which showed homogeneous morphology (mean size of 1.7 ± 0.5 μm), a protective effect of the drug, and better antifungal effect against Candida culture than miconazole nitrate and the other assayed systems. Taking into account these results, this approach should be seriously considered for further evaluation of its safety and in vivo efficacy to be considered as an alternative therapeutic system for the treatment of oral candidiasis.

Mechanochemistry of nucleosides, nucleotides and related materials

The application of mechanical force to induce the formation and cleavage of covalent bonds is a rapidly developing field within organic chemistry which has particular value in reducing or eliminating solvent usage, enhancing reaction rates and also in enabling the preparation of products which are otherwise inaccessible under solution-phase conditions. Mechanochemistry has also found recent attention in materials chemistry and API formulation during which rearrangement of non-covalent interactions give rise to functional products. However, this has been known to nucleic acids science almost since its inception in the late nineteenth century when Miescher exploited grinding to facilitate disaggregation of DNA from tightly bound proteins through selective denaturation of the latter. Despite the wide application of ball milling to amino acid chemistry, there have been limited reports of mechanochemical transformations involving nucleoside or nucleotide substrates on preparative scales. A survey of these reactions is provided, the majority of which have used a mixer ball mill and display an almost universal requirement for liquid to be present within the grinding vessel. Mechanochemistry of charged nucleotide substrates, in particular, provides considerable benefits both in terms of efficiency (reducing total processing times from weeks to hours) and by minimising exposure to aqueous conditions, access to previously elusive materials. In the absence of large quantities of solvent and heating, side-reactions can be reduced or eliminated. The central contribution of mechanochemistry (and specifically, ball milling) to the isolation of biologically active materials derived from nuclei by grinding will also be outlined. Finally non-covalent associative processes involving nucleic acids and related materials using mechanochemistry will be described: specifically, solid solutions, cocrystals, polymorph transitions, carbon nanotube dissolution and inclusion complex formation.

Biopolymeric nano/microspheres for selective and reversible adsorption of coronaviruses

A novel biopolymeric material in the form of nano/microspheres was developed which was capable of adsorbing coronaviruses. The biopolymer was obtained by crosslinking of chitosan (CHIT) with genipin, a nontoxic compound of plant origin, in inverted emulsion and reacting the chitosan nano/microspheres obtained (CHIT-NS/MS) with glycidyltrimethyl-ammonium chloride (GTMAC). As a result the nano/microspheres of N-(2-hydroxypropyl)-3-trimethyl chitosan (HTCC-NS/MS) were obtained. HTCC-NS/MS were studied as the adsorbents of human coronavirus NL63 (HCoV-NL63), mouse hepatitis virus (MHV), and human coronavirus HCoV-OC43 particles in aqueous virus suspensions. By studying cytopathic effect (CPE) caused by these viruses and performing PCR analyses it was found HTCC-NS/MS strongly adsorb the particles of HCoV-NL63 virus, moderately adsorb mouse hepatitis virus (MHV) particles, but do not adsorb HCoV-OC43 coronavirus. The adsorption capacity of HTCC-NS/MS well correlated with the antiviral activity of soluble HTCC against a given virus. Importantly, it was shown that HCoV-NL63 particles could be desorbed from the HTCC-NS/MS surface with a salt solution of high ionic strength with retention of virus virulence. The obtained material may be applied for the removal of coronaviruses, purification and concentration of virus samples obtained from biological matrices and for purification of water from pathogenic coronaviruses.

Heterogeneous polymer composite nanoparticles loaded in situ gel for controlled release intra-vaginal therapy of genital herpes

Herpes simplex virus causes serious and contagious genital infections in high percentage of female population world-wide. Acyclovir is a clinically successful antiviral molecule till date, in-spite of limitations as poor solubility, low half-life, reduced oral bioavailability and side effects at higher doses. In the present work, controlled release in situ gelling system loaded with polymeric nanoparticles of acyclovir containing a dose of drug equivalent to 105mg/day has been developed. The formulation containing drug loaded polyvinyl pyrrolidone-Eudragit RSPO hybrid polymeric nanoparticles (Size ∼99±3nm, Zeta ∼+26.1±1.5mV) in 15% Pluronic F-127 gel exhibited improved permeability through vaginal membrane (KP=2.20±0.19×10(-6)cm/s). The nanoparticles showed enhanced viability for vaginal epithelial cell lines up to concentration of 100-250μg/mL. The formulation was evaluated for bioavailability and biodistribution through intra-vaginal administration in rat models. The nanoparticle in situ gel formulation maintained an average therapeutic drug level of 0.6±0.2μg/mL in plasma for 24h. Significant improvement in mean residence time of the drug (12.52±1.12h) was observed with a two-fold increase in the relative bioavailability (AUC0-24h=14.92±2.44μgh/mL) compared to that of the pure drug (7.18±1.79μgh/mL). The tissue distribution was 2-3 folds higher in animals treated with nanoparticles in situ gel compared to that of pure drug. Sustained release of drug in vivo was demonstrated, ensuring the suitability of the formulation for clinical therapy in female population.

Formulation design of oral pediatric Acetazolamide suspension: dose uniformity and physico-chemical stability study

CONTEXT

The formulation of an active pharmaceutical ingredient (API) as oral solution or suspension in pediatrics is a habitual practice, due to the non-existence of many commercialized medicines in pediatric doses. It is also the simplest way to prepare and administer them to this vulnerable population. The design of a formulation that assures the dose and the system stability depends on the physico-chemical properties of the API.

OBJECTIVE

In this study, we formulate a class IV API, Acetazolamide (AZM) as suspension for oral administration to pediatric population. The suspension must comply attributes of quality, safety and efficacy for this route of administration.

MATERIALS AND METHODS

We use simple compounding procedures, as well as fewer pure excipients, as recommended for children. Mass and uniformity content assays and physical and chemical stability studies were performed. To quantify the API an UPLC method was used.

RESULTS AND DISCUSSION

We verified the physico-chemical stability of the suspensions and that they passed the mass test of the European Pharmacopeia (EP), but not the dose uniformity test.

CONCLUSIONS

This reveals that AZM must be formulated as liquid forms with a more complex system of excipients (not usually indicated in pediatrics), or otherwise solid forms capable of assuring uniformity of mass and dose for every dosage unit.