Bioavailability of hydrochlorothiazide from pellets, made by extrusion/spheronisation, containing polyethylene glycol 400 as a dissolution enhancer

Egg White Protein Carrier-Assisted Development of Solid Dispersion for Improved Aqueous Solubility and Permeability of Poorly Water Soluble Hydrochlorothiazide

Hydrochlorothiazide (HTZ) is a first-line drug used in the treatment of hypertension suffered from low oral bioavailability due to poor aqueous solubility and permeability. Hence, lyophilized egg white protein-based solid dispersion (HTZ-EWP SD) was developed to explore its feasibility as a solid dispersion carrier for enhanced aqueous solubility and permeability of HTZ. The HTZ-EWP SD was prepared using the kneading method. HTZ-EWP SD was characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FT-IR), powder X-ray diffractometer (PXRD), solubility, in vitro dissolution, and ex vivo permeation studies. The physico-chemical evaluation suggested the formation of the solid dispersion. Optimized HTZ-EWP SD4 drastically enhanced (~32-fold) aqueous solubility (~16.12 ± 0.08 mg/mL) over to pure HTZ (~ 0.51 ± 0.03 mg/mL). The dissolution study in phosphate buffer media (pH 6.8) revealed that HTZ-EWP SD4 significantly enhanced the release rate of HTZ (~ 87 %) over to HTZ (~ 25 %). The permeation rate of HTZ from optimized HTZ-EWP SD4 was enhanced significantly (~ 84 %) compared to pure HTZ (~ 24 %). Optimized HTZ-EWP-SD4 enhanced the rate of HTZ dissolution (~ 86 %) in FeSSIF (fed state simulated intestinal fluid), compared to a low dissolution rate (~ 72 %) in FaSSIF (fasted state simulated intestinal fluid) state after 2-h study. Obtained results conclude that lyophilized egg white protein can be utilized as an alternative solid dispersion carrier for enhancing the solubility and permeability of HTZ.

Population-based meta-analysis of hydrochlorothiazide pharmacokinetics

Hydrochlorothiazide (HCTZ) is a thiazide diuretic used for the treatment of hypertension and edema associated with fluid overload conditions such as congestive heart failure (CHF). A population-based meta-analysis approach in NONMEM® was used to develop a PK model to characterize the time-course of HCTZ concentrations in plasma and excretion into the urine for healthy subjects and CHF patients. Data from healthy subjects receiving 100 mg of oral HCTZ were supplemented with additional plasma concentration and urinary excretion versus time data published in the literature following administration of oral HCTZ doses ranging from 10 to 500 mg to healthy subjects or patients with renal failure, CHF or hypertension. A two-compartment model with first-order oral absorption, using a Weibull function, and first-order elimination best described HCTZ PK. Creatinine clearance (CLCR ) was a statistically significant predictor of renal clearance (CLR ). Non-renal clearance was estimated to be 2.44 l/h, CLR was 18.3 l/h and T1/2,α was 1.6 h and T1/2,β was 14.8 h for a typical individual with normal renal function (CLCR  = 120 ml/min). However, CLR was reduced to 10.5, 5.47 and 2.70 l/h in mild (CLCR  = 80 ml/min), moderate (CLCR  = 50 ml/min) and severe (CLCR  = 30 ml/min) renal impairment, respectively. Model diagnostics helped to demonstrate that the population PK model reasonably predicts the rate of urinary HCTZ excretion over time using dosing history and estimated CLCR , allowing for the convenient assessment of PK-PD relationships for HCTZ when given alone or in combination with other agents used to treat fluid overload conditions.

A new way of stabilization of furosemide upon cryogenic grinding by using acylated saccharides matrices. The role of hydrogen bonds in decomposition mechanism

Recently it was reported that upon mechanical milling of pure furosemide significant chemical degradation occurs (Adrjanowicz et al. Pharm. Res.2011, 28, 3220-3236). In this paper, we present a novel way of chemical stabilization amorphous furosemide against decomposing that occur during mechanical treatment by preparing binary mixtures with acylated saccharides. To get some insight into the mechanism of chemical degradation of furosemide induced by cryomilling, experimental investigations supported by density functional theory (DFT) computations were carried out. This included detailed studies on molecular dynamics and physical properties of cryoground samples. The main thrust of our paper is that we have shown that furosemide cryomilled with acylated saccharides forms chemically and physically stable homogeneous mixtures with only one glass transition temperature, Tg. Finally, solubility measurements have demonstrated that furosemide cryomilled with acylated saccharides (glucose, maltose and sucrose) is much more soluble with respect to the crystalline form of this active pharmaceutical ingredient (API).

ToF-SIMS analysis of chemical heterogenities in inkjet micro-array printed drug/polymer formulations

Three different formulations comprising two drugs, felodipine and hydrochlorothiazide (HCT) and two polymers, poly(vinyl pyrolidone) (PVP) and poly(lactic-co-glycolic acid) (PLGA) were inkjet printed as micro-dot arrays and analysed on an individual micro-spot basis by time-of-flight secondary ion mass spectrometry (ToF-SIMS). For the HCT/PLGA formulation, the spots showed heterogeneity of the drug and other chemical constituents. To further investigate these heterogeneities, multivariate curve resolution was applied to the ToF-SIMS hyperspectral image datasets. This approach successfully identified distinct chemical components elucidating the HCT, PLGA, substrate material, and contaminants based on sulphur, phosphorous and sodium chloride. Spots printed using either of the drugs with PVP exhibited full substrate coverage and a uniform distribution of the active ingredient along with all other constituents within the printed spot area. This represents the preferred situation in terms of stability and controlling the release of a drug from a polymer matrix.

Molecular dynamics of the cryomilled base and hydrochloride ziprasidones by means of dielectric spectroscopy

Cryomilling was applied to obtain amorphous forms of the base ziprasidone and its hydrochloride salt. Complete amorphization of both samples was confirmed by differential scanning calorimetry and X-ray measurements. As it turned out, cryogrinding is very effective way to obtain these drugs in the amorphous state, especially because melting of both ziprazidones accompanies significant chemical decomposition as revealed by ultra performance liquid chromatography examination. Consequently, the glassy state cannot be reached in conventional way, that is, by supercooling of melt. Broadband dielectric relaxation measurements were performed on both drugs to describe their molecular dynamics above as well as below their glass transition temperatures (T(g)). We found out that ziprasidone base and its hydrochloride salt differ in T(g) in the same way as it was previously reported for tramadol monohydrate and its hydrochloride. Moreover, our dielectric studies revealed that molecular mobility is not the main factor controlling kinetics of crystallization of both ziprasidones above their T(g) . Below the T(g) relaxation related to water as well as secondary relaxation process originating from the intermolecular interaction (Johari-Goldstein) were identified in the loss spectra of both materials. We have demonstrated that except of local mobility, water is the dominant factor moving both ziprasidones toward recrystallization process. Finally, we have also carried out solubility measurements to show that dissolution rate of the amorphous ziprasidones is much higher with respect to the crystalline samples.

The influence of non-ionic surfactants on the rheological properties of drug/microcrystalline cellulose/water mixtures and their use in the preparation and drug release performance of pellets prepared by extrusion/spheronization

The influence of adding two concentrations (5 and 25%) of non-ionic surfactants, one hydrophilic and the other hydrophobic, plus mixtures of equal parts of the two, on the rheological properties of a mixture of equal parts of microcrystalline cellulose and ibuprofen with water has been assessed by capillary rheometry. The mixtures were also used to form pellets by extrusion/spheronization and their in vitro dissolution in simulated intestinal fluid was measured. As with previous rheological studies of these types of pastes, the flow was non-Newtonian (shear thinning). Other rheological parameters were determined in terms of die entry angles, extensional flow and elastic parameters of recoverable shear and compliance. By comparisons with previous studies with the model drug, it was found that it was these latter parameters that were indicative of the ability of the formulations to produce satisfactory pellets. The experiments also identified that the level of surfactant as opposed to the type of surfactant determined the rheological properties of the wet mass. All the formulations were able to produce round pellets with a narrow size distribution, whereby their median size increased with the concentration of the surfactant. The 25% level of each of the surfactant formulations provided a rapid release of the drug (100% within 30min), but the 5% level and the mixed surfactant formulations provided lower drug release profiles.

Immediate release of poorly soluble drugs from starch-based pellets prepared via extrusion/spheronisation

The aim of this study was to evaluate modified starch (high-amylose, crystalline and resistant starch) as the main excipient for immediate-release pellets containing poorly soluble drugs (hydrochlorothiazide and piroxicam) and prepared via extrusion/spheronisation. The bioavailability of pellets (containing 50 mg hydrochlorothiazide) was determined after oral administration to 6 dogs. A 2(4)-factorial design with central point was used to evaluate the influence of hydrochlorothiazide (10% and 50%, w/w), HPMC (binder, 4% and 7%, w/w), sorbitol (0% and 10%, w/w) and water (granulation liquid, low and high level) on pellet yield, size (Feret mean diameter) and sphericity (aspect ratio and two-dimensional shape factor, eR). Optimal granulation liquid content depended on drug and sorbitol level in the formulation. All factors except sorbitol content, as well as the interactions between drug concentration and binder level and between drug and water level, were significant (P<0.05) for pellet yield, while a significant curvature (P<0.05) suggested non-linearity of the response plots. The model was not significant for pellet shape, while hydrochlorothiazide and water level as well as their interaction were significant (P<0.05) for pellet size. Pellet friability, disintegration, residual water content and in-vitro drug release were determined. Pellets containing 2.5% (w/w) piroxicam were also evaluated. For both model drugs, pellets with a high yield (>90%), acceptable sphericity (AR<1.2) and low friability (<0.01%) were obtained. Due to pellet disintegration, fast dissolution of both hydrochlorothiazide and piroxicam was achieved: >80% drug released in 30 min. The bioavailability (AUC0-->24 h, Cmax and tmax) of hydrochlorothiazide pellets in dogs was not significantly different from fast-disintegrating immediate-release hydrochlorothiazide tablets (P>0.05).

Bioavailability of hydrochlorothiazide from isomalt-based moulded tablets

The bioavailability of hydrochlorothiazide (HCT) from moulded isomalt-based tablets was evaluated after oral administration of 50 mg HCT to healthy volunteers as an oral moulded tablet and as a lozenge, in comparison with a conventional tablet formulation (Dichlotride 50 mg). Moulded tablets had a high relative bioavailability (F(rel)) as the pharmacokinetic parameters (C(max), t(max), t(1/2), AUC(0-->24 h)) determined from HCT plasma concentration versus time profiles were not significantly different (P>0.05; two-way ANOVA) in comparison with the conventional tablet. The relative bioavailability of the moulded tablet administered as a lozenge and as an oral tablet was 106.2+/-30.9% and 89.4+/-25.9%, respectively, in relation to the conventional tablet formulation. Direct moulding of isomalt tablets proved to be a suitable technique to administer a poorly soluble drug either as a conventional tablet or as a lozenge.

Stability of freeze-dried tablets at different relative humidities

The purpose of the study was to evaluate the stability of two different freeze-dried tablet formulations at different relative humidities (RHs). The tablets contained 25 mg hydrochlorothiazide (HCT) as a model drug and were prepared by freeze-drying a suspension and an oil-in-water (o/w) emulsion. Formulation A was a rapidly disintegrating tablet and consisted of 80 mg of maltodextrine DE38; 8 mg of polyethyleneglycol (PEG 6000), 8 mg of xanthan gum, and 25 mg of HCT. Formulation B was a lyophilized dry emulsion tablet that consisted of 160 mg of Miglyol 812, 80 mg of maltodextrin DE38, 16 mg of methylcellulose (Methocel) A15LV, and 25 mg of HCT. Tablets were packaged in different packing materials: polyvinylchloride (PVC)/aluminum blister packs, PVC-polyvinylidenechloride (PVDC)/aluminum blister packs, closed containers with a dessicant tablet, and open containers. The tablets were stored at three relative humidities (45%, 60%, and 85% RH) and were characterized on mechanical strength, residual moisture, porosity, content uniformity, and scanning electron microscopy (SEM) during a period of 6 months. After 1 month at 60% and 85% RH, a strong increase in moisture content (from 2.7% to 6.8%) was seen for the tablets packed in the open and closed containers and for the PVC/aluminum blistered tablets. This increase was higher for formulation A compared to formulation B since B contained 160 mg of triglycerides and was more hydrophobic. This increase in water content was correlated with a decrease in mechanical strength. The tablets also showed a change in microstructure and porosity. At a moisture content of 7.2%, formulation A showed a structural "collapse" since water acts as a plasticizer for the amorphous glass, lowering the glass transition temperature Tg. This phenomenon even occurred in PVC/aluminum blister packs at 85% RH. The structural collapse was associated with a complete loss of microstructure as detected by porosimetric analysis and SEM. For the PVC-PVDC/aluminum blistered tablets, the increase in moisture content and decrease in mechanical strength at 85% RH occurred much slower, and the water uptake and strength loss were less intensive. No significant breakdown of HCT could be observed in both formulations with all of the packing materials. Packaging of freeze-dried tablets with PVC/aluminum blister packs, PVC/PVDC/aluminum blister packs, or closed containers did not offer protection against moisture uptake, mechanical strength loss, and structural collapse.