Application of Accelerated Predictive Stability Studies in Extemporaneously Compounded Formulations of Chlorhexidine to Assess the Shelf Life

Industrially fabricated medicines have a well-defined shelf life supported by rigorous studies before their approval for commercialization. However, the shelf life of extemporaneous compounding topical formulations prepared at hospitals tends to be shorter, especially when no data are available to prove a longer stability period. Also, the storage conditions are unknown in many circumstances. Accelerated Predictive Stability (APS) studies have been shown to be a useful tool to predict in a faster and more accurate manner the chemical stability of extemporaneously compounded formulations requiring a minimum amount of formulation, thereby reducing the chemical drug waste per study. Shelf life will be allocated based on scientific data without compromising drug efficacy or safety. In this work, the APS approach was applied to the commercially available Cristalmina® (CR) and an extemporaneously compounded formulation of chlorhexidine (DCHX). A different degradation kinetic was found between DCHX and CR (Avrami vs. zero-order kinetics, respectively). This can explain the different shelf life described by the International Council for Harmonisation of Technical Requirements Registration Pharmaceuticals Human Use (ICH) conditions between both formulations. A predicted stability for the DCHX solution was obtained from the extrapolation of the degradation rate in long-term conditions from the Arrhenius equation. The estimated degradation from the Arrhenius equation for DCHX at 5 °C, 25 °C, and 30 °C at 365 days was 3.1%, 17.4%, and 25.9%, respectively. The predicted shelf life, in which the DCHX content was above 90%, was 26.67 months under refrigerated conditions and 5.75 and 2.24 months at 25 and 30 °C, respectively. Currently, the Spanish National Formulary recommends a shelf life of no longer than 3 months at room temperature for DCHX solution. Based on the predicted APS and confirmed by experimental long-term studies, we have demonstrated that the shelf life of DCHX extemporaneously compounded formulations could be prolonged by up to 6 months.

Co-Delivery of a High Dose of Amphotericin B and Itraconazole by Means of a Dry Powder Inhaler Formulation for the Treatment of Severe Fungal Pulmonary Infections

Over the past few decades, there has been a considerable rise in the incidence and prevalence of pulmonary fungal infections, creating a global health problem due to a lack of antifungal therapies specifically designed for pulmonary administration. Amphotericin B (AmB) and itraconazole (ITR) are two antifungal drugs with different mechanisms of action that have been widely employed in antimycotic therapy. In this work, microparticles containing a high dose of AmB and ITR (20, 30, and 40% total antifungal drug loading) were engineered for use in dry powder inhalers (DPIs) with an aim to improve the pharmacological effect, thereby enhancing the existing off-label choices for pulmonary administration. A Design of Experiment (DoE) approach was employed to prepare DPI formulations consisting of AmB-ITR encapsulated within γ-cyclodextrin (γ-CD) alongside functional excipients, such as mannitol and leucine. In vitro deposition indicated a favourable lung deposition pattern characterised by an upper ITR distribution (mass median aerodynamic diameter (MMAD) ~ 6 µm) along with a lower AmB deposition (MMAD ~ 3 µm). This offers significant advantages for treating fungal infections, not only in the lung parenchyma but also in the upper respiratory tract, considering that Aspergillus spp. can cause upper and lower airway disorders. The in vitro deposition profile of ITR and larger MMAD was related to the higher unencapsulated crystalline fraction of the drug, which may be altered using a higher concentration of γ-CD.

Engineering of 3D printed personalized polypills for the treatment of the metabolic syndrome

Metabolic syndrome is a collection of abnormalities, including at least three of the following insulin resistance, hypertension, dyslipidemia, type 2 diabetes, obesity, inflammation, and non-alcoholic fatty liver disease. 3D printed solid dosage forms have emerged as a promising tool enabling the fabrication of personalized medicines and offering solutions that cannot be achieved by industrial mass production. Most attempts found in the literature to manufacture polypills for this syndrome contain just two drugs. However, most fixed-dose combination (FDC) products in clinical practice required the use of three or more drugs. In this work, Fused deposition modelling (FDM) 3D printing technology coupled with Hot-melt extrusion (HME) has been successfully applied in the manufacture of polypills containing nifedipine (NFD), as an antihypertensive drug, simvastatin (SMV), as an antihyperlipidemic drug, and gliclazide (GLZ) as an antiglycemic drug. Hanssen solubility parameters (HSPs) were utilized as predictors to guide the formation of amorphous solid dispersion between drug and polymer to ensure miscibility and enhanced oral bioavailability. The HSP varied from 18.3 for NFD, 24.6 for SMV, and 7.0 for GLZ while the total solubility parameter for the excipient mixture was 27.3^0.5. This allowed the formation of an amorphous solid dispersion in SMV and GLZ 3D printed tablets compared to NFD which was partially crystalline. Popypill showed a dual release profile combining a faster SMV release (< 6 h) with a 24 h sustained release for NDF and GLZ. This work demonstrated the transformation of FDC into dynamic dose-personalized polypills.

Targeting lung macrophages for fungal and parasitic pulmonary infections with innovative amphotericin B dry powder inhalers

The incidence of fungal pulmonary infections is known to be on the increase, and yet there is an alarming gap in terms of marketed antifungal therapies that are available for pulmonary administration. Amphotericin B (AmB) is a highly efficient broad-spectrum antifungal only marketed as an intravenous formulation. Based on the lack of effective antifungal and antiparasitic pulmonary treatments, the aim of this study was to develop a carbohydrate-based AmB dry powder inhaler (DPI) formulation, prepared by spray drying. Amorphous AmB microparticles were developed by combining 39.7 % AmB with 39.7 % γ-cyclodextrin, 8.1 % mannose and 12.5 % leucine. An increase in the mannose concentration from 8.1 to 29.8 %, led to partial drug crystallisation. Both formulations showed good in vitro lung deposition characteristics (80 % FPF < 5 µm and MMAD < 3 µm) at different air flow rates (60 and 30 L/min) when used with a DPI, but also during nebulisation upon reconstitution in water.

Can amphotericin B and itraconazole be co-delivered orally? Tailoring oral fixed-dose combination coated granules for systemic mycoses

The incidence and prevalence of invasive fungal infections have increased significantly over the last few years, leading to a global health problem due to the lack of effective treatments. Amphotericin B (AmB) and itraconazole (ITR) are two antifungal drugs with different mechanisms of action. In this work, AmB and ITR have been formulated within granules to elicit an enhanced pharmacological effect, while enhancing the oral bioavailability of AmB. A Quality by Design (QbD) approach was utilised to prepare fixed-dose combination (FDC) granules consisting of a core containing AmB with functional excipients, such as inulin, microcrystalline cellulose (MCC), chitosan, sodium deoxycholate (NaDC) and Soluplus® and polyvinyl pyrrolidone (PVP), coated with a polymeric layer containing ITR with Soluplus® or a combination of Poloxamer 188 and hydroxypropyl methyl cellulose-acetyl succinate (HPMCAS). A Taguchi design of experiments (DoE) with 7 factors and 2 levels was carried out to understand the key factors impacting on the physicochemical properties of the formulation followed by a Box-Behnken design with 3 factors in 3 levels chosen to optimise the formulation parameters. The core of the FDC granules was obtained by wet granulation and later coated using a fluidized bed. In vitro antifungal efficacy was demonstrated by measuring the inhibition halo against different species of Candida spp., including C. albicans (24.19-30.48 mm), C. parapsilosis (26.38-27.84 mm) and C. krusei (11.48-17.92 mm). AmB release was prolonged from 3 to 24 h when the AmB granules were coated. In vivo in CD-1 male mice studies showed that these granules were more selective towards liver, spleen and lung compared to kidney (up to 5-fold more selective in liver, with an accumulation of 8.07 µg AmB/g liver after twice-daily 5 days administration of granules coated with soluplus-ITR), resulting in an excellent oral administration option in the treatment of invasive mycosis. Nevertheless, some biochemical alterations were found, including a decrease in blood urea nitrogen (∼17 g/dl) and alanine aminotransferase (<30 U/l) and an increase in the levels of bilirubin (∼0.2 mg/dl) and alkaline phosphatase (<80 U/l), which could be indicative of a liver failure. Once-daily regimen for 10 days can be a promising therapy.

Amphotericin B Formulations and Drug Targeting

Amphotericin B is a low-soluble polyene antibiotic which is able to self-aggregate. The aggregation state can modify its activity and pharmacokinetical characteristics. In spite of its high toxicity it is still widely employed for the treatment of systemic fungal infections and parasitic disease and different formulations are marketed. Some of these formulations, such as liposomal formulations, can be considered as classical examples of drug targeting. The pharmacokinetics, toxicity and activity are clearly dependent on the type of amphotericin B formulation. New drug delivery systems such as liposomes, nanospheres and microspheres can result in higher concentrations of AMB in the liver and spleen, but lower concentrations in kidney and lungs, so decreasing its toxicity. Moreover, the administration of these drug delivery systems can enhance the drug accessibility to organs and tissues (e.g., bone marrow) otherwise inaccessible to the free drug. During the last few years, new AMB formulations (AmBisome, Abelcet, and Amphotec) with an improved efficacy/toxicity ratio have been marketed. This review compares the different formulations of amphotericin B in terms of pharmacokinetics, toxicity and activity and discusses the possible drug targeting effect of some of these new formulations.

Comparative pharmacokinetics and safety of a novel lyophilized amphotericin B lecithin-based oil-water microemulsion and amphotericin B deoxycholate in animal models

Amphotericin B (AmB) has been a most effective systemic antifungal agent, but its use is circumscribed by the dose-limiting toxicity of the conventional micellar dispersion formulation Fungizone (D-AmB). To lower AmB-associated toxicity, AmB may be integrated into oil-in-water lecithin-based microemulsions. The present study compares the pharmacokinetic characteristics of D-AmB with the alternative formulation of AmB in microemulsion (M-AmB), which has proved effective in a murine candidiasis model. Both formulations were given by intravenous bolus: D-AmB 1 mg/kg, and M-AmB 0.5, 1 or 2 mg/kg. The pharmacokinetics of D-AmB and M-AmB have several differences, specifically with regard to the respective Cmax and AUC0- infinity values. Elimination of AmB from serum was biphasic for both M-AmB and D-AmB. Single-dose D-AmB (1 mg/kg) achieved a Cmax of 3.89 +/- 0.48 mg/L and an AUC0- infinity of 32.28 +/- 7.31 mg.h/L, whereas single-dose M-AmB (1 mg/kg) by comparison achieved a lower Cmax (2.92 +/- 0.54 mg/L) and a lower AUC0- infinity (21.89 +/- 5.17 mg.h/L). To evaluate the safety of M-AmB, a multiple-dose toxicity study was performed in groups of 10 mice, each receiving D-AmB 1 mg/kg, or M-AmB 1, 1.5, 2 or 3 mg/kg. The findings suggest that, in comparison with D-AmB, M-AmB produces no histologically demonstrable renal lesions, or changes in clinical chemistry.

Lecithin-based oil-in-water microemulsions for parenteral use: pseudoternary phase diagrams, characterization and toxicity studies

Pseudoternary phase diagrams have been constructed to evaluate the phase behavior of systems containing water/lecithin/polysorbate 80/isopropyl myristate at different polysorbate 80:lecithin weight ratios (K(m)). Oil-in-water microemulsion regions were accurately determined and the influence of the K(m) on the area of existence of such disperse systems was also examined. Viscosity studies as well as particle size analysis by dynamic light scattering were carried out on oil-water microemulsions, and the influence of the oil phase content, the total amount of surfactants and K(m) on the rheological behavior, viscosity, and droplet size of such disperse systems was evaluated. All systems studied showed a water-rich isotrope region (oil-in-water microemulsion area), that was seen to be highly dependent upon the surfactant/cosurfactant weight ratio. Most of the microemulsions analyzed showed a non-Newtonian rheological behavior and both, droplet size, and viscosity of the disperse systems, were found to be much more influenced by the total content of oil phase and surfactants present in the microemulsion than by the K(m). The selected system underwent both stability and in vivo acute toxicity studies, and seemed to be highly stable, even at extreme conditions, and very low toxic according to the results obtained.

Lyophilized lecithin based oil-water microemulsions as a new and low toxic delivery system for amphotericin B

PURPOSE

To develop and investigate lecithin based oil-water microemulsions as potential amphotericin B (AmB) delivery systems and to evaluate their in vivo acute toxicity.

METHODS

AmB was added to the microemulsion and its location was evaluated by partitioning studies and UV-visible spectrophotometric analysis of the drug. Both, non-lyophilized and reconstituted microemulsions were characterised and assessed for their stability. Single-dose acute toxicity of the AmB microemulsion was studied on male albino Webster-derived CD-1 mice and compared with Fungizone.

RESULTS

The studies performed showed that AmB was intercalated on the oil-water interface of the microemulsion as a complex formed with lecithin molecules. AmB addition did not seem to modify the rheological properties of the original system, but had an effect on its particle size distribution. Lyophilization of the microemulsion led to an oily cake, easily reconstituted and stable at the conditions studied. Single-dose acute toxicity studies proved that the LD50 of AmB microemulsions was of 4 mg kg(-1) of animal weight, compared with 1 mg kg(-1) found for Fungizone.

CONCLUSIONS

Lyophilized lecithin based oil-water microemulsions appear to be valuable systems for the delivery of AmB in terms of easy and low-cost manufacturing, stability and safety compared with the formulations already in market.

Preparation and in vitro characterization of gelatin microspheres containing Levodopa for nasal administration

Transnasal absorption of pharmaceutical drugs has been recognized as an interesting alternative to the more conventional routes of administration. The aim of this paper was to develop a method of administrating L-dopa following the transnasal route. Gelatin microspheres were prepared by the w/o emulsification solvent extraction technique: the microspheres had a median particle size of 16.2 +/- 4.2 microm and were prepared using a stirring speed of 600 rpm for 5 min at 80 degrees C. The microspheres obtained were spherical and smooth-surfaced, and the microsphere size was inversely proportional to stirring speed (300-700 rpm) and to the percentage of the emulsifier (Tween 85, 1.4-2.7% v/v). L-dopa was incorporated into the microspheres with an efficiency of 65 +/- 6.7%. L-dopa was released from the microspheres, showing an initial fast release rate, followed by a second slower release rate.

Release of nortriptyline hydrochloride from oil-water microemulsions

The release of nortritptyline hydrochloride from oil-in-water (o/w) microemulsions (isopropyl myristate as oil, propylene glycol as cosurfactant, polysorbate 80 as surfactant and phosphate buffer, pH 7.4, as the continuous phase) containing increasing concentrations of polyethylene glycol 400, used to facilitate the diffusion of a drug from the inner oily phase of the microemulsion to the outer aqueous phase of such a dispersion system, was studied by determining the permeability constants of the drug through hydrophilic and lipophilic membranes separating the o/w microemulsions from the receiving aqueous phase (phosphate buffer pH 7.4). The permeability of nortriptyline hydrochloride from microemulsions through the lipophilic membrane increased as the concentration of polyethylene glycol 400 in the disperse system increased. The apparent permeability constant for nortriptyline hydrochloride, from the microemulsion without polyethylene glycol, was 1.36 x 10(-3) cm x h(-1), it increased up to 7.80 x 10(-3) cm x h(-1) in the presence of polyethylene glycol at a concentration of 50% (v/v) of the initial volume of the aqueous phase.

Interaction of poly methyl vinyl ether/maleic anhydride-dimiristoyl phosphatidylcholine: a model bioadhesion study

The objective of this work is to study the interaction of a copolymer, poly methyl vinyl ether/maleic anhydride (PMV/MA) used in pharmaceutical dosage form and a phospholipid L-alpha-dimiristoyl phosphatidylcholine (DMPC) with the aim of developing a bioadhesive system. Glycerine is the plastifiant used to make PMV/MA insoluble. We have studied copolymer-plastifiant compatibility with differential scanning calorimetry and we have studied the influence that the solvents produce on the copolymer by infrared spectroscopy. Monolayer experiments were carried out with a Wilhelmy-type surface balance. The purpose of these experiments is to obtain molecular information about interaction PMV/MA-glycerine system with DMPC. The results show that there are attractive forces and it is a spontaneous process.

Comparison of UV spectrophotometric and LC methods for the determination of nortriptyline hydrochloride in polysorbate 80 based oil/water (o/w) microemulsions

A new rapid, reliable and specific UV spectrophotometric method was developed for the determination of nortriptyline hydrochloride formulated into o/w microemulsions. The UV spectra of nortriptyline standard solution in methanol and placebo (microemulsion without nortriptyline) were recorded over the wavelength range 200-600 nm and the spectra for placebo and nortriptyline loaded microemulsion were recorded over the range 260-400 nm in order to determine the overlapping that might appears, and hence to set the wavelength that could be used for the quantitative analysis. This method was validated and compared with a liquid chromatography (LC) procedure used for the quantitative analysis of the drug. Both methods showed excellent precision and accuracy with RSD values of 2.37 and 1.41%, respectively, for the LC method, and values of 1.24 and 2.88%, respectively, for the UV spectrophotometric method. The established linearity range was 10-50 microg ml(-1) (r2 = 0.9985) and 20-60 microg ml(-1) (r2 = 0.9979) for the HPLC and UV spectrophotometric methods respectively. The recoveries of nortriptyline from spiked placebos were > 95% for both methods over the linear range. The methods have been successfully used for determining the nortriptyline content of microemulsions and for evaluating the chemical stability of the drug in nortriptyline-loaded microemulsions.

Analysis of diclofenac sodium and derivatives

There are two reasons explaining why several researchers have carried out the in vitro release studies of diclofenac sodium (DFNa) using pH media of above 6.5. Firstly the pH dependence of solubility, and secondly the intramolecular cyclization suffered under acidic conditions which causes the salt to become inactivated. Nevertheless, many commercially available pharmaceutical dosage forms have no protective coat to avoid the inactivation in the gastric juices. A possible explanation may be found if reconstitution of the cyclated form takes place. It is therefore necessary to study the behaviour of diclofenac sodium when it is submitted to the action of different solutions in a wide pH range. To perform this study five analytical methods have been employed: UV-vis spectrophotometry, differential scanning calorimetry (DSC), infrared analysis (IR), X-ray diffractometry (DRX) and energy dispersive X-ray analysis (EDS).

Solvent and plasticizer influences on ethylcellulose-microcapsules

Variations in microencapsulation processes give rise to different products and it seems there are no firm rules. It is thus difficult to know what kind of product will be obtained before the research is carried out. Changes in temperature, rate, time and type of stirring can cause great modifications in the system, most of which are responsible for variations in standard techniques. In our study, we investigate the solvent influence on ethylcellulose (EC) microcapsule formation. We have selected four different solvents: ethanol as an aqueous solvent and acetone, chloroform and toluene as organic solvents. Diclofenac sodium (DFNa), a non-steroidal anti-inflammatory agent, has been used as an encapsulated substance as it is inactivated in the gastric juices. This polymer and microencapsulation process was selected after an exhaustive study with different polymers and processes. Once the solvent influence was determined, ethylphthalate was incorporated in one type of microcapsule in order to study the influence of this plasticizer on drug release by the modification of film-permeability.