Development of an amorphous nanosuspension by sonoprecipitation-formulation and process optimization using design of experiment methodology.

A Design of Experiment (DoE) methodology was adopted to investigate and optimize process parameters and formulations variables for preparing an amorphous clotrimazole (CLT) nanosuspension by sonoprecipitation technique. The amorphous nanosuspension can provide a synergistic effect of increase in dissolution velocity and kinetic solubility which can be advantageously used to improve bioavailability of low-solubility drugs. A Box-Behnken design was utilized to study the effect of formulation parameters (drug concentration, polymer concentration, and surfactant concentration) and process parameter (antisolvent: solvent ratio) on particle size, polydispersibility index (PDI), and zeta potential of amorphous CLT nanoparticles. Soluplus® and poloxamer 407 were incorporated in the formulation for steric and electrostatic stabilization respectively. The optimized formulation predicted by the developed model was validated experimentally. The micronized amorphous suspension, micronized crystalline suspension and nanocrystalline suspension were prepared as controls. The optimized amorphous nanosuspension and controls were characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and polarized light microscopy (PLM) techniques. Additionally, in-vitro dissolution studies were performed. The drug concentration, polymer concentration and antisolvent:solvent ratio were found to be statistically significant in impacting critical quality attributes (CQAs) of drug product. The model developed for zeta potential was insignificant at a 95% confidence interval. The DSC, XRPD and PLM results confirmed the amorphization of CLT by sonoprecipitation process. The DSC thermogram did not show any characteristic endothermic peak, XRPD diffractogram showed amorphous halo pattern whereas PLM images did not illustrate birefringence for amorphous CLT nanosuspension. The in-vitro drug dissolution studies demonstrated relatively higher drug dissolution for amorphous CLT nanosuspension compared to controls at both the dissolution media (de-ionized water and pH 7.2 buffer). The sonoprecipitation process was successfully used to produce a stable amorphous nanosuspension with notably enhanced dissolution velocity by evaluating and optimizing critical process and formulation parameters.

Investigating a Novel Hot Melt Extrusion-Based Drying Technique to Solidify an Amorphous Nanosuspension Using Design of Experiment Methodology.

The hot melt extrusion (HME) technology was explored and optimized to solidify an amorphous nanosuspension using Quality by Design (QbD) methodology. A design of experiments (DoE) approach was used to perform a set of 15 experiments, varying independent variables (feed rate, input temperature, and screw speed) within a design space. Redispersibility index (RDI), moisture content, and process yield constituted the critical quality attributes (CQAs) of the experimental design. Regression analysis and ANOVA were employed to identify and estimate significant main effects and two-way interactions, and model the process of HME drying for predictive purposes. The optimized HME-dried end product was characterized for physicochemical properties using differential scanning calorimetry (DSC), X-ray powder diffractions (XRPD), polarized light microscopy (PLM), Fourier transform infrared spectroscopy (FTIR), and in vitro dissolution studies. The statistical analysis reveals feed rate and input temperature as significant independent variables, critically influencing RDI and moisture content of solidified end product. The model developed for process yield was insignificant at a p-value of 0.05. The API retained its amorphous nature after the extrusion process which was confirmed using DSC and XRPD techniques. PLM was unsuitable to differentiate and determine crystallinity of drug moiety in the presence of a semi-crystalline bulking agent, microcrystalline cellulose (MCC). In vitro dissolution study depicted solubility and dissolution enhancement for HME-dried amorphous nanosuspension in both the dissolution media which can be attributed to amorphous nature of nanosized drug particles. A well-designed study implemented by DoE aided in developing a robust and novel HME technique to dry aqueous nanosuspension.

A quality-by-design study to develop Nifedipine nanosuspension: examining the relative impact of formulation variables, wet media milling process parameters and excipient variability on drug product quality attributes.

Wet milling is a multifunctional and the most common method to prepare a drug nanosuspension for improving the bioavailability of poorly water soluble drugs. A suitable way of preparing a high drug-loaded nifedipine nanosuspension using wet stirred media milling was investigated in the present study. Nifedipine, a poorly water soluble drug, was selected as a model drug to enhance its dissolution rate and oral bioavailability by preparing an appropriate crystalline nanosuspension. Process parameters, such as milling media volume, milling speed and milling time, were optimized using the one variable at a time (OVAT) approach. A similar method was used to select an appropriate polymeric stabilizer and a surfactant from different categories of polymeric stabilizers (HPC SL, HPC SSL Soluplus®, Kollidon® VA 64 and HPMC E 15) and surfactants (Poloxamer 407, Kolliphor TPGS and Docusate sodium). A systematic optimization of critical formulation parameters (such as drug concentration, polymer concentration and surfactant concentration) was performed with the aid of the Box-Behnken design. Mean particle size, polydispersity index and zeta potential as critical quality attributes (CQAs) were selected in the design for the evaluation and optimization of the formulation and validation of the improved product. The nifedipine nanosuspension that was prepared using HPC and poloxamer 407 was found to be most stable with the lowest mean particle size as compared with the formulations prepared using other polymeric stabilizers and surfactants. The optimized formulation was further spray-dried and characterized using the Fourier Transform Infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), polarized light microscopy (PLM) and in-vitro dissolution study. Results have shown no interaction between the drug particles and stabilizers, nor a reduction in the crystallinity of drug, nor an increase in the saturation solubility and rapid in vitro dissolution as compared with pure nifedipine crystals. Thus, the current study supports the suitability of the wet stirred media milling method and a combination of HPC SSL and poloxamer 407 as stabilizers for the preparation of nifedipine nanosuspension.

Influence of processing methods on physico-mechanical properties of Ibuprofen/HPC-SSL formulation.

The objective of the present study was to investigate the influence of processing methods on the physical and mechanical properties of formulations containing Ibuprofen and HPC-SSL. The powder blends, containing Ibuprofen and HPC-SSL in ratio of 9:0.5, were processed using melt granulation (MG) by hot melt extrusion (HME) and wet granulation (WG) by high shear mixer. Formulated granules and powder blends were compressed into round flat faced tablets using Riva Piccola tablet press. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) studies proved that granulation process did not significantly alter the crystallinity of Ibuprofen, however, particle density and flow properties were significantly improved. Scanning electron microscopy (SEM) and particle size analysis corroborate with the findings that the flow characteristics of granules from MG were relatively superior to other formulations. Formulations were investigated for out-of-die compaction behaviour using Heckel, Kawakita, and CTC profile analysis. Detailed examination revealed that all three formulations differed in particle size due to the granulation, thus conferring to different compaction behaviour. In WG and MG, granulation offered an increase in particle size resulting in high compressibility along with deformation at low compression pressure. This results into low yield pressure, low yield strength, and higher densification, as compared with dry blend. The current work provides an insight into factors affecting physical and mechanical properties tablets, which can facilitate the rational selection of suitable change in processing method instead of changing excipients.

Investigate the effect of solvents on wet granulation of microcrystalline cellulose using hydroxypropyl methylcellulose as a binder and evaluation of rheological and thermal characteristics of granules.

Wet granulation is the most commonly used technique in the pharmaceutical industry for delivering oral solid dosage forms. In wet granulation, the binder solvent is one of the critical factors affecting granule properties. In the current study, an attempt was made to investigate the effect of solvents (aqueous and hydro-alcoholic) on thermal and flow properties of Microcrystalline Cellulose (MCC) granules prepared using two different grades of Hydroxypropyl Methylcellulose (HPMC), which served as an effective binder. The granulation endpoint was evaluated using thermal effusivity sensor. Rheometer and Modulated Differential Scanning Calorimetry (mDSC) was used to study the flow and thermal properties of wet and dried granules. Furthermore, physical characterization was carried out by granule strength, particle size distribution and tablet hardness for all granules under the study. Thermal effusivity sensor results indicate 55% w/w concentration of binder solution as the endpoint by measuring thermal effusivity for both binders. Additionally, powder rheometer results show that the wet granules of hydro-alcoholic batches show greater resistance to flow whereas the dried granules display excellent flow characteristics as evident from Basic flowability energy values and specific energy values. Permeability results suggest that the granules formed with hydro-alcoholic binder solvent exhibit better porosity and permeability. Tablet hardness data showed that tablets formulated using hydro-alcoholic solvent granules have greater hardness than tablets formulated using water based solvent granules. The granule strength for water based granules is relatively higher than that of hydro-alcoholic based granules. mDSC thermograms show a sharp rise in enthalpy value at 55% w/w binder solution which is indicative of a more significant amount of solvent being present on the surface of granules and formation of optimal granules. To summarize, we have determined a technique to measure endpoint determination and simultaneously investigate the role of solvent systems on the rheology of MCC granules, which could assist in selecting an appropriate solvent system for granulation.

Fusion Method for Solubility and Dissolution Rate Enhancement of Ibuprofen Using Block Copolymer Poloxamer 407.

Aim of current research was to prepare ibuprofen-poloxamer 407 binary mixtures using fusion method and characterize them for their physicochemical and performance properties. Binary mixtures of ibuprofen and poloxamer were prepared in three different ratios (1:0.25, 1:0.5, and 1:0.75, respectively) using a water-jacketed high shear mixer. In vitro dissolution and saturation solubility studies were carried out for the drug, physical mixtures, and formulations for all ratios in de-ionized water, 0.1 N HCl (pH = 1.2), and phosphate buffer (pH = 7.2). Thermal and physical characterization of samples was done using modulated differential scanning calorimetry (mDSC), X-ray powder diffraction (XRD), and infrared spectroscopy (FTIR). Flow properties were evaluated using a powder rheometer. Maximum solubility enhancement was seen in acidic media for fused formulations where the ratio 1:0.75 had 18-fold increase. In vitro dissolution studies showed dissolution rate enhancement for physical mixtures and the formulations in all three media. The most pronounced effect was seen for formulation (1:0.75) in acidic media where the cumulative drug release was 58.27% while for drug, it was 3.67%. Model independent statistical methods and ANOVA based methods were used to check the significance of difference in the dissolution profiles. Thermograms from mDSC showed a characteristic peak for all formulations with Tpeak of around 45°C which suggested formation of a eutectic mixture. XRD data displayed that crystalline nature of ibuprofen was intact in the formulations. This work shows the effect of eutectic formation and micellar solubilization between ibuprofen and poloxamer at the given ratios on its solubility and dissolution rate enhancement.