Testosterone solid lipid microparticles for transdermal drug delivery. Formulation and physicochemical characterization

Enhanced alveo pulmonary deposition of nebulized ciclesonide for attenuating airways inflammations: a strategy to overcome metered dose inhaler drawbacks

Ciclesonide (CIC), an inhaled corticosteroid for bronchial asthma is currently available as metered dose inhaler (CIC–MDI) which possesses a major challenge in the management of the elderly, critically ill patients and children. In this work, nebulized CIC nano-structure lipid particles (CIC-NLPs) were prepared and evaluated for their deep pulmonary delivery and cytotoxicity to provide additional clinical benefits to patients in controlled manner and lower dose. The bio-efficacy following nebulization in ovalbumin (OVA) induced asthma Balb/c mice compared to commercial (CIC–MDI) was also assessed. The developed NLPs of 222.6 nm successfully entrapped CIC (entrapment efficiency 93.3%) and exhibited favorable aerosolization efficiency (mass median aerodynamic diameter (MMAD) 2.03 μm and fine particle fraction (FPF) of 84.51%) at lower impactor stages indicating deep lung deposition without imparting any cytotoxic effect up to a concentration of 100 μg/ml. The nebulization of 40 µg dose of the developed CIC-NLPs revealed significant therapeutic impact in the mitigation of the allergic airways inflammations when compared to 80 µg dose of the commercial CIC–MDI inhaler (Alvesco^®). Superior anti-inflammatory and antioxidative stress effects characterized by significant decrease (p< .0001) in inflammatory cytokines IL-4 and 13, serum IgE levels, malondialdehyde (MDA), nitric oxide (NO), TNF-α, and activated nuclear factor-κB (NF-κB) activity were obvious with concomitant increase in superoxide dismutase (SOD) activity. Histological examination with inhibition of inflammatory cell infiltration in the respiratory tract was correlated well with observed biochemical improvement.

Analytical Techniques for the Assessment of Drug-Lipid Interactions and the Active Substance Distribution in Liquid Dispersions of Solid Lipid Microparticles (SLM) Produced de novo and Reconstituted from Spray-Dried Powders

Solid lipid microparticles (SLM) can be presented as liquid suspension or spray-dried powder. The main challenge in SLM technology is to precisely determine the location of the active substance (API) in the different compartments of the formulation and its changes during SLM processing. Therefore, the purpose of the research was to assess the distribution of the API and to investigate the nature of the API-lipid interaction when the formulation was subjected to spray drying, with an indication of the most suitable techniques for this purpose. SLM were prepared with two various lipids (Compritol or stearic acid) and two model APIs: cyclosporine (0.1% and 1% w/w) and spironolactone (0.1% and 0.5% w/w). Physicochemical characterizations of the formulations, before and after spray drying, were performed by differential scanning calorimetry (DSC), atomic force microscopy (AFM), Raman spectroscopy and nuclear magnetic resonance (NMR). The API distribution between the SLM matrix, SLM surface and the aqueous phase was determined, and the release study was performed. It was demonstrated that, in general, the spray drying did not affect the drug release and drug distribution; however, some changes were observed in the SLM with Compritol and when the API concentration was lower. Only in the SLM with stearic acid was a change in the DSC curves noted. Measurements with the AFM technique proved to be a useful method for detecting differences in the surface properties between the placebo and API-loaded SLM, while the Raman spectroscopy did not show such evident differences.

Evaluation of the Properties of Encapsulated Stavudine Microparticulate Lipid-based Drug Delivery System in Immunocompromised Wistar Rats

BACKGROUND

Lipid-based formulations have been confirmed to lower some side effects of drugs and can be tailor-made to offer sustained drug release of drugs with short half-life like stavudine.

AIM

This study aimed to evaluate the immunomodulatory properties of stavudine-loaded solid lipid microparticles (SLMs) using immunocompromised Wistar rats.

METHODS

The SLMs were formulated by the homogenization method. The optimized batches were used for further in vivo studies. The effect of formulation on the CD4 count and the haematological properties of immunocompromised Wistar rats were studied.

RESULTS

The particle size range was 4 -8 μm, EE range was 85-93 % and maximum drug release was observed at 10 h. The CD4 cells increased from 115 ± 3.17 cell/mm3 at day zero to 495 ± 5.64 cell/mm3 at day 14 of treatment and 538 ± 6.31 cell/mm3 at day 21. The red blood cells increased from 2.64 ± 1.58 (x 106/mm3) at day zero to 6.96 ± 3.47 (x 106/mm3) at day 14 and 7.85 ± 3.64 (x 106/mm3) at day 21. PCV increased significantly (p < 0.05) to about 42-50 % at day 21 in the groups that received the SLMs formulations. White blood cells (WBC) also were 12 x 103/mm3, for SLM formulations, while the rats that received plain stavudine exhibited WBC of 9.6 x 103/mm3 at day 21. The histopathological studies revealed that oral stavudine-loaded SLMs had no significant damage to the kidney, liver, spleen and the brain of Wistar rats.

CONCLUSION

The formulations exhibited significantly higher immunomodulatory properties than plain stavudine (p<0.05) and showed good properties for once daily oral administration and could be a better alternative to plain stavudine tablets for the management of patients living with HIV.

Evaluation of dika wax-soybean oil-based artesunate-loaded lipospheres: in vitro-in vivo correlation studies

OBJECTIVES

To formulate and evaluate artesunate-loaded lipospheres and study the in vitro-in vivo correlations (IV-IVC).

MATERIALS AND METHODS

Lipospheres were formulated by melt homogenisation using structured lipid matrices consisting of (1:3 and 1:6) soybean oil and dika wax and were characterised in vitro and in vivo.

RESULTS

The small angle X-ray diffraction (SAXD) results of the lipid matrices showed prominent reflection at 2θ = 2.49°, d = 3.55 Å while, wide angle X-ray diffraction (WAXD) showed prominent reflection at 2θ = 20.83°, d = 0.42 Å. Lipospheres had maximum encapsulation efficiency of 80%, showed no significant decrease in pH with time (p < 0.05), and had sustained release properties. The ratio of the area under the curve (AUC) of the lipospheres and the tablets gave bioavailability enhancement factor of 2.108.

CONCLUSION

Artesunate-loaded lipospheres could be used orally or parenterally once daily, for the treatment of malaria.

Formulation development and evaluation of the anti-malaria properties of sustained release artesunate-loaded solid lipid microparticles based on phytolipids

CONTEXTS: Artemisinins and its derivatives are considered the basis in the treatment of Plasmodium falciparum malaria due to their high potency and rapid action. However, they have short half life, low solubility, and poor oral bioavailability, hence the need to formulate sustained release lipid particulate dosage form of these drugs.

OBJECTIVES

To formulate and evaluate artesunate-loaded solid lipid microparticles (SLMs) based on structured lipid matrices consisting of soybean oil and dika wax.

MATERIALS AND METHODS

The lipid matrices were characterized by differential scanning calorimetry (DSC), small-angle X-ray diffraction (SAXD), and wide-angle X-ray diffraction (WAXD). The SLMs were prepared by hot melt-homogenization. Time-dependent particle size analysis, time-dependent pH stability studies, encapsulation efficiency (EE%), and in vitro drug release were carried out on the SLMs. In vivo anti-malarial studies were performed using a modified Peter's 4-day suppressive protocol using Plasmodium berghei infected mice.

RESULTS AND DISCUSSION

Thermograms of the lipid matrices showed modifications in the microstructure of dika wax as a result of inclusion of soybean oil. SAXD and WAXD diffractograms showed that the lipid matrices were found to be non-lamellar. Particle size of SLM increased with time, while the pH was almost constant. The SLMs had maximum EE% of 80.6% and sustained the release of artesunate more than the reference tablet. In vivo pharmacodynamic studies showed that the SLMs had significant (p < 0.05) reduction in parasitaemia compared with reference tablet.

CONCLUSION

Artesunate-loaded SLMs could be used once daily in the treatment of malaria.

Evaluation of solid lipid microparticles produced by spray congealing for topical application of econazole nitrate

Objectives

The aims of this study were to evaluate the suitability of the spray congealing technique to produce solid lipid microparticles (SLMs) for topical administration and to study the skin permeation of a drug from SLMs compared with solid lipid nanoparticles (SLNs).

Methods

Econazole nitrate was used as model drug and Precirol ATO 5 as the lipidic carrier. SLMs and SLNs were both prepared at 5: 1, 10: 1 and 12.5: 1 lipid: drug weight ratios and characterised in terms of particle size, morphology, encapsulation efficiency and chemical analysis of the particle surface. SLMs and SLNs were also incorporated into HPMC K 100M hydrogels for ex-vivo drug permeation tests using porcine epidermis.

Key findings

SLMs had particle sizes of 18–45 μm, while SLNs showed a mean diameter of 130–270 nm. The encapsulation efficiency was 80–100%. Permeation profiles of econazole nitrate were influenced by both particle size (significant difference until 9 h) and the amount of lipid.

Conclusions

The results confirm the usefulness of SLNs as carriers for topical administration and suggest the potential of SLMs for the delivery of drugs to the skin.

Developing an emulsifier system to improve the bioaccessibility of carotenoids

Food emulsion designs, with the aim of delivering lipophilic bioactive compounds, should include an estimate of their bioaccessibility to support the claimed effect. With this goal in mind, in vitro digestion models and experimental design of mixtures were used as analytical tools to measure this parameter and to optimize the formulation of an O/W emulsion, including carotenoids as functional ingredients. Two experimental stages were applied. First, a screening phase was completed to detect the critical factors that exerted a significant effect on the response (bioaccessibility). During this phase, we observed that the response was modified mainly by secondary effects such as synergies and antagonisms of the emulsifying mixture. A group of four emulsifiers was selected at this phase to perform the second experimental stage, the optimization phase. This allowed us to obtain the mixture that produced the maximum carotenoid bioaccessibility. This formulation had emulsifying properties of the liposugars, acyl- and polyacyl-glycerides, as well as the synergistic effect arising from the combination of materials; this maximized the response. The analytical approach applied in this work is of interest for food designers for screening and controlling the bioaccessibility of bioactive compounds in a given matrix and, consequently, selecting the formulation conditions for higher bioaccessibilities.