Brief on Recent Application of Liposomal Vaccines for Lower Respiratory Tract Viral Infections: From Influenza to COVID-19 Vaccines.

Vaccination is the most effective means of preventing infectious diseases and saving lives. Modern biotechnology largely enabled vaccine development. In the meantime, recent advances in pharmaceutical technology have resulted in the emergence of nanoparticles that are extensively investigated as promising miniaturized drug delivery systems. Scientists are particularly interested in liposomes as an important carrier for vaccine development. Wide acceptability of liposomes lies in their flexibility and versatility. Due to their unique vesicular structure with alternating aqueous and lipid compartments, liposomes can enclose both hydrophilic and lipophilic compounds, including antigens. Liposome composition can be tailored to obtain the desired immune response and adjuvant characteristics. During the current pandemic of COVID-19, many liposome-based vaccines have been developed with great success. This review covers a liposome-based vaccine designed particularly to combat viral infection of the lower respiratory tract (LRT), i.e., infection of the lung, specifically in the lower airways. Viruses such as influenza, respiratory syncytial virus (RSV), severe acute respiratory syndrome (SARS-CoV-1 and SARS-CoV-2) are common causes of LRT infections, hence this review mainly focuses on this category of viruses.

An Overview of the Antioxidant Effects of Ascorbic Acid and Alpha Lipoic Acid (in Liposomal Forms) as Adjuvant in Cancer Treatment.

Antioxidants are known to minimize oxidative stress by interacting with free radicals produced as a result of cell aerobic reactions. Oxidative stress has long been linked to many diseases, especially tumours. Therefore, antioxidants play a crucial role in the prevention or management of free radical-related diseases. However, most of these antioxidants have anticancer effects only if taken in large doses. Others show inadequate bioavailability due to their instability in the blood or having a hydrophilic nature that limits their permeation through the cell membrane. Therefore, entrapping antioxidants in liposomes may overcome these drawbacks as liposomes have the capability to accommodate both hydrophilic and hydrophobic compounds with a considerable stability. Additionally, liposomes have the capability to accumulate at the cancer tissue passively, due to their small sizes, with enhanced drug delivery. Additionally, liposomes can be engineered with targeting moieties to increase the delivery of chemotherapeutic agents to specific tumour cells with decreased accumulation in healthy tissues. Therefore, combined use of liposomes and antioxidants, with or without chemotherapeutic agents, is an attractive strategy to combat varies tumours. This mini review focuses on the liposomal delivery of selected antioxidants, namely ascorbic acid (AA) and alpha-lipoic acid (ALA). The contribution of these nanocarriers in enhancing the antioxidant effect of AA and ALA and consequently their anticancer potentials will be demonstrated.

Spironolactone release from liquisolid formulations prepared with Capryol™ 90, Solutol® HS-15 and Kollicoat® SR 30 D as non-volatile liquid vehicles.

The purpose of the study is to enhance dissolution of spironolactone as a model hydrophobic drug through application of liquisolid technology. Spironolactone is prepared as liquisolid formulations, and its dissolution property is evaluated and compared to that of conventional spironolactone tablets and pure spironolactone. Three non-volatile liquid vehicles were used in the design of spironolactone liquisolid formulations, Capryol™ 90, Synperonic® PE/L61 in combination with Solutol® HS-15 at a ratio of 1:1, and Kollicoat® SR 30 D. Spironolactone liquisolid formulations were tested according to British Pharmacopoeia (BP) quality control tests. Furthermore, the prepared liquisolid powder formulations were evaluated via differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) and scanning electron microscopy. Also, liquisolid formulations were subjected to testing of storage stability at high relative humidity. The results indicated that most of liquisolid tablets met the BP requirements. Dissolution results indicate that release of spironolactone was significantly increased (P<0.05) through liquisolid formulations, compared to pure drug. Liquisolid powder formulations formulated from a combination of Synperonic® PE/L61-Solutol® HS-15 showed highest dissolution. DSC thermograms from liquisolid formulations revealed that drug endothermic peak was disappeared after processing. Dissolution, DSC and FT-IR data after storage demonstrated that there were no significant changes in the formulations after storage. In conclusion, the liquid vehicles used within spironolactone liquisolid formulations enhanced drug dissolution rate.

Preparation and characterization of domperidone solid dispersions.

Domperidone is a highly water insoluble drug exhibiting poor dissolution pattern. The purpose of this work was to increase the dissolution rate of Domperidone by formation of solid dispersion with different water soluble carriers. Binary systems of Domperidone were prepared with polyvinyl pyrrolidone k-30 (PVP), poloxamer 188 (P188) and polyethylene glycol 6000 (PEG 6000) at different weight ratios using the solvent evaporation method, physical mixtures of the same systems were also used. The effect of the method of preparation was also investigated by preparing some selected formulations using melting method. As P188 is known to inhibit CYP3A4 enzyme which is responsible for hepatic metabolism of many drugs including Domperidone, the effect of incorporation of PVP or PEG 6000 as ternary component to P188 solid dispersion on dissolution rate was also investigated. Formulations were characterized by Fourier transform infrared (FTIR) and Differential scanning calorimetry (DSC). Drug content uniformity and dissolution rate were studied. Solid dispersions showed a better dissolution compared to the pure drug and physical mixtures, with PVP showing the highest dissolution efficiency. As indicated from DSC data, Domperidone was in the amorphous form, which confirmed the better dissolution rate of solid dispersions. Some ternary P188 combinations showed a better enhancement in drug dissolution compared to the optimized P188 binary system. This would present a potential of increasing oral bioavailability of Domperidone by increasing its dissolution rate and by inhibiting its pre-systemic metabolism by the presence of P188.

Liquisolid technique to enhance and to sustain griseofulvin dissolution: effect of choice of non-volatile liquid vehicles.

Liquisolid systems were originally designed to enhance dissolution of hydrophobic drugs. Recently, the same technique was explored to control drug release via hydrophobic carriers. This work aimed to study the effects of different liquid vehicles on release characteristics of griseofulvin as a model hydrophobic drug. Fast dissolution tablets were prepared using three different non-ionic surfactants namely Cremophor(®)EL, Synperonic(®)PE/L61 and Capryol™ 90, on the contrary Kollicoat(®)SR 30D was used for production of grieseofulvin sustained release formulations. Avicel(®) PH102 and Cab-O-Sil(®) M5 were used as carrier and coat materials, respectively. The effect of formulation parameters, such as drug concentration and carrier to coat ratio, on enhancing drug dissolution was explored. Drug concentrations of 20% and 40% (w/w), and R-values (carrier to coat ratio) of 10 and 20 were used. The mathematical model was utilized to formulate liquisolid powder systems. All fast release liquisolid formulations showed higher percentage drug dissolution efficiency (%DE) than conventional directly compacted tablets. Cremophor(®)EL showed the best dissolution enhancement with %DE of about 90%, compared to only 23% for conventional tablets; DSC data suggested loss of griseofulvin crystallinity and thermal behavior. Kollicoat(®) SR 30D retarded the drug release even in the presence of hydrophilic carrier; DSC data suggested that only small fraction of the drug was present in the molecular state within the system. The used liquisolid vehicles showed promise to enhance and to control (depend on the choice of the liquid vehicle) the release of griseofulvin from liquisolid compacts.