Fine powder of lipid microparticles – spray drying process development and optimization

Drug Release from Lipid Microparticles-Insights into Drug Incorporation and the Influence of Physiological Factors

The aim of this study was to assess the impact of physiological factors, namely tear fluid and lysozyme enzyme, as well as surfactant polysorbate, on the release profile from solid lipid microparticles (SLM), in the form of dispersion intended for ocular application. Indomethacin (Ind) was used as a model drug substance and a release study was performed by applying the dialysis bag method. Conducting release studies taking into account physiological factors is expected to improve development and screening studies, as well as support the regulatory assessment of this multi-compartment lipid dosage form. The effect of the lysozyme was directly related to its effect on lipid microparticles, as it occurred only in their presence (no effect on the solubility of Ind). Polysorbate also turned out to be an important factor interacting with the SLM surface, which determined the release of Ind from SLM. However, in study models without tear fluid or lysozyme, the release of Ind did not exceed 60% within 96 h. Ultimately, only the simultaneous application of artificial tear fluid, lysozyme, and polysorbate allowed for the release of 100% of Ind through the SLM dispersion. The examination of the residues after the release studies indicated the possibility of releasing 100% of Ind from SLM without complete degradation of the microparticles' matrix. The incubation of SLM with tear fluid confirmed a similar influence of physiological factors contained in tear fluid on the surface structure of SLM as that observed during the in vitro studies.

On the Feasibility of Rugose Lipid Microparticles in Pressurized Metered Dose Inhalers with Established and New Propellants

Pressurized metered dose inhalers (pMDIs) require optimized formulations to provide stable, consistent lung delivery. This study investigates the feasibility of novel rugose lipid particles (RLPs) as potential drug carriers in pMDI formulations. The physical stability of RLPs was assessed in three different propellants: the established HFA-134a and HFA-227ea and the new low global-warming-potential (GWP) propellant HFO-1234ze. A feedstock containing DSPC and calcium chloride was prepared without pore forming agent to spray dry two RLP batches at inlet temperatures of 55 °C (RLP55) and 75 °C (RLP75). RLPs performance in pMDI formulations was compared to two reference samples that exhibit significantly different performance when suspended in propellants: well-established engineered porous particles and particles containing 80% trehalose and 20% leucine (80T20L). An accelerated stability study at 40 °C and relative humidity of 7% ± 5% was conducted over 3 months. At different time points, a shadowgraphic imaging technique was used to evaluate the colloidal stability of particles in pMDIs. Field emission electron microscopy with energy dispersive X-ray spectroscopy was used to evaluate the morphology and elemental composition of particles extracted from the pMDIs. After 2 weeks, all 80T20L formulations rapidly aggregated upon agitation and exhibited significantly inferior colloidal stability compared to the other samples. In comparison, both the RLP55 and RLP75 formulations, regardless of the propellant used, retained their rugose structure and demonstrated excellent suspension stability comparable with the engineered porous particles. The studied RLPs demonstrate great potential for use in pMDI formulations with HFA propellants and the next-generation low-GWP propellant HFO-1234ze.

Optimization of spray dried yogurt and its application to prepare functional cookies

Introduction

Spray-dried yogurt powder (SDYP) has shelf stability and other functional properties that improve solubility and facilitate the use, processing, packaging, and transportation of other food derivatives, such as bread and pastries on a large scale. The present research was conducted to develop SDYP and further its utilization to prepare functional cookies.

Methods

Yogurt was spray-dried by employing different outlet air temperatures (OAT) (65°C, 70°C & 75°C) and inlet air temperature (IAT) (150°C, 155°C & 160°C). Spray drying shows that increasing the temperature increases nutritional loss, whereas S. thermophilus culture shows resistance to the intensive heat approaches. On the other hand L. delbrueckii subsp. Bulgaricus culture was found to be significantly affected. A total of 4 treatments, including one control for the functional cookies development.

Results and discussion

A directly proportional relation was investigated between the increasing concentration of SDYP and baking characteristics and cookie's mineral and protein profile. Bioactive parameters like antioxidant activity of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and total phenolic content (TPC) were also affected significantly. The sensory profile shows an incline towards T0 (0% SDYP) to T3 (10% SDYP) in all attributes but starts to decline when the concentration of SDYP reaches 15%. This study suggests that by employing a certain combination of temperatures (OAT: 60°C IAT: 150°C); maximum survival of inoculated culture can be achieved, and this powder can be utilized in the development of functional cookies with enhanced sensory as well as biochemical characteristics significantly (P< 0.05).

Comparative Study of Cinnamon and Paprika Oleoresins Encapsulated by Spray Chilling and Particles from Gas Saturated Solutions Techniques: Evaluation of Physical Characteristics and Oleoresins Release in Food Simulated Media

In this study, cinnamon and paprika oleoresins were encapsulated by two technologies, respectively, spray chilling and particles from gas saturated solutions. Both technologies used palm oil as wall materials. The physical characteristics of the microparticles were compared as well as the oleoresins release behavior in high- and low-fat simulated food media. The spray chilling microparticles had an average diameter of 143.7 ± 1.5 µm, spherical shape, smooth surface, and passable flow property. In contrast, microparticles obtained by particles from gas saturated solutions (PGSS) showed an average diameter of 105.7 ± 0.6 µm, irregular shape, porous surface, poor flow property but higher encapsulation efficiency. In evaluating the compounds released in a simulated food medium, the spray chilling particles delivered 30.7%, while PGSS reached 23.1% after 1 h. Both microparticles well fitted the Kosmeyer-Peppas (R2 = 0.98 and 0.96 for spray chilling and PGSS) and Peppas-Sahlin models (R2 = 0.98 and 0.97 for spray chilling and PGSS). However, spray chilling microparticles showed a diffusion mechanism, while for PGSS ones erosion was the main mechanism. Despite the different physical characteristics, both microparticles proved to be possible facilitators in delivering oleoresins in food products.

Comparison of the In Vitro Drug Release Methods for the Selection of Test Conditions to Characterize Solid Lipid Microparticles

The release profiles of active substances from microspheres are one of the most important features in solid lipid microparticles (SLM) characterization. Unfortunately, the results of the dissolution tests are largely dependent on the chosen method and test conditions, which in relation to novel dosage forms, such as dispersions of lipid microspheres, are not clearly defined in international compendiums and guidelines. This makes it impossible to compare the results of different studies. The aim of the research was to identify the factors most influencing the variability of the obtained results. An attempt was also made to select the most appropriate method for testing drug substance release from SLM. Various dissolution methods were employed (method I: without a membrane, method II: in a dialysis bag, and method III: in a Side-Bi-Side chamber), and the obtained release profiles of cyclosporine and indomethacin from SLM dispersions were compared. In addition to the effect of membranes, the types of acceptor fluids were also investigated. Significant differences were observed when testing the SLM formulations under various test conditions. The results were significantly influenced by the selected membrane, the acceptor fluid, or the difference in the concentrations of active substance between the donor and acceptor compartments. The burst effect observed in some experimental methods was not noticed in other conditions. At this stage, the method with a dialysis bag has been selected as the most suitable, while the methods without the membrane can only play a complementary role.

Spray-Drying of Hydroxypropyl β-Cyclodextrin Microcapsules for Co-Encapsulation of Resveratrol and Piperine with Enhanced Solubility

The synergistic therapeutic benefits of resveratrol (RES) and piperine (PIP) have been proven for the treatment of various diseases. This study reports, for the first time, spray-drying of hydroxypropyl β-cyclodextrin (HP-β-CD) microcapsules for combined delivery of resveratrol and piperine. Phase solubility studies indicated that there was a strong interaction between the active ingredients and HP-β-CD, and both active ingredients can bind stably to HP-β-CD. The results of FTIR, XRD, and DSC demonstrated that RES-PIP/HP-β-CD inclusion complexes were successfully formed, with the RES and PIP encapsulated into the hollow spherical cavity of HP-β-CD. The results of SEM showed that the spray-dried microcapsules displayed a smooth surface and uniform particle size. Upon the formation of the spray-dried microcapsules, both RES and PIP presented significantly enhanced solubility. The results of DPPH and ABTS+ scavenging activity assays showed that the spray-drying process did not adversely influence the antioxidant activity of the bioactives, and the addition of PIP increased the antioxidation performance of RES.

Distribution of Drug Substances in Solid Lipid Microparticles (SLM)—Methods of Analysis and Interpretation

The incorporation of drug substances into the matrix of solid lipid microparticles (SLM) is critical to providing effects such as prolonged release, taste masking, and protection of the labile API. Currently, a commonly used method of characterizing multi-compartment lipid systems, such as SLM, is to determine entrapment efficiency (EE) and drug loading (DL) parameters, but this is not sufficient for understanding the localization of API either in the core or on the surface of the microspheres. The main objective of the research was to study the distribution of API in an aqueous dispersion of SLM in order to distinguish between the API incorporated in the lipid matrix and localized in the superficial region (interphase) and to refer the obtained results to the EE and DL parameters. SLM dispersions (10–30% of the lipid) with four model drug substances, i.e., cyclosporine, clotrimazole, diclofenac sodium and hydrocortisone, were prepared and investigated. In the first stage, the experiments were designed to optimize the method of extracting the API fraction localized on the SLM surface by shaking the dispersions with methanol. The fraction dissolved in the aqueous phase was obtained by ultrafiltration of SLM dispersions. Total drug content and the concentration in the separated phases were determined by the HPLC method. The obtained results were compared with the EE and DL parameters. Selected SLM dispersions were tested both before and after thermal sterilization. Short-term shaking of SLM dispersion with methanol does not damage the lipid matrix and allows the API fraction localized on the SLM surface to be extracted, the result of which was the determination of API distribution between lipid matrix, interphase and aqueous phase. It was found that the majority of API represented by EE value was localized on the surface of SLM. Only for cyclosporine was the incorporation of drug molecules in the lipid core very effective (up to 48%), while for other drug substances only 1–21% was found in the lipid core of SLM. A clear influence of the sterilization process on the distribution of API within the microparticles was found. The presented studies showed that the characterization of multi-compartment SLM dispersions solely on the basis of EE and DL values, is insufficient. The proposed new distribution test method enables the localization of API to be demonstrated within the microspheres, with the quantitative characteristics of the drug fraction incorporated in the lipid matrix and the fraction associated with the surface of the lipid matrix. The proposed new method allows the influence of the sterilization process on the changes in the API distribution within the lipospheres to be evaluated. Such characteristics provide new opportunities for the development and use of this dosage form as a carrier providing prolonged release and other aforementioned advantages.

Whey Proteins Isolate-Based Biopolymeric Combinations to Microencapsulate Supercritical Fluid Extracted Oleoresins from Sea Buckthorn Pomace

In this study, high-value, carotenoid-rich oleoresin obtained by supercritical carbon dioxide (SFE-CO₂) extraction was used to develop five variants of microencapsulated delivery system, based on whey proteins isolate (WPI), in combination with inulin (I), pectin (P) or lactose (L). The WPI:I and WPI:L variants were also obtained by conjugation via Maillard reaction. The microencapsulation of the SFE-CO₂ sea buckthorn pomace oleoresin was performed by emulsion, complex coacervation and freeze-drying, which allowed for the obtaining of five powders, with different phytochemicals profile. The WPI:I conjugate showed the highest level of total carotenoids, whereas the counterpart WPI:L showed the highest content in linoleic acid (46 ± 1 mg/g) and palmitoleic acid (20.0 ± 0.5 mg/g). The β-tocopherol and β-sitosterol were identified in all variants, with the highest content in the conjugated WPI:L variant. Both WPI:L and WPI:I conjugate samples presented similar IC50 value for inhibitory activity against pancreatic lipase and α-amylase; the highest activity was observed for the conjugated WPI:I. The WPI:P combination allowed the highest release of carotenoids in the gastro-intestinal environment. All the powders exhibited poor flowing properties, whereas water activity (a_w) ranged from 0.084 ± 0.03 to 0.241 ± 0.003, suggesting that all variants are stable during storage. In case of solubility, significant differences were noticed between non-heated and glycated samples, with the highest value for the WPI:I and the lowest for glycated WPI:I. The structural analysis revealed the presence of finer spherosomes in WPI:I and WPI:L, with a reduced clustering capacity, whereas the particles in the conjugated samples were more uniform and aggregated into a three-dimensional network.