In Vitro Evaluation of a Solid Supersaturated Self Nanoemulsifying Drug Delivery System (Super-SNEDDS) of Aprepitant for Enhanced Solubility

Aprepitant (APR) belongs to Class II of the Biopharmaceutical Classification System (BCS) because of its low aqueous solubility. The objective of the current work is to develop self-nanoemulsifying drug delivery systems (SNEDDS) of APR to enhance its aqueous solubility. Preformulation studies involving screening of excipients for solubility and emulsification efficiency were carried out. Pseudo ternary phase diagrams were constructed with blends of oil (Imwitor® 988), cosolvent (Transcutol® P), and various surfactants (Kolliphor® RH40, Kolliphor® ELP, Kolliphor® HS15). The prepared SNEDDS were characterized for droplet size and nanoemulsion stability after dilution. Supersaturated SNEDDS (super-SNEDDS) were prepared to increase the quantity of loaded APR into the formulations. HPMC, PVP, PVP/VA, and Soluplus® were used as polymeric precipitation inhibitors (PPI). PPIs were added to the formulations at 5% and 10% by weight. The influence of the PPIs on drug precipitation was investigated. In vitro lipolysis test was carried out to simulate digestion of formulations in the gastrointestinal tract. Optimized super-SNEDDS were formulated into free-flowing granules by adsorption on the porous carriers such as Neusilin® US2. In vitro dissolution studies of solid super-SNEDDS formulation revealed an increased dissolution rate of the drug due to enhanced solubility. Consequently, a formulation to improve the solubility and potentially bioavailability of the drug was developed.

Enhanced Loading Efficiency and Mucoadhesion Properties of Gellan Gum Thin Films by Complexation with Hydroxypropyl-β-Cyclodextrin

Polymeric oral thin films (OTFs) were prepared by the casting method, combining gellan gum (GG), a water-soluble polysaccharide, and glycerol (Gly) as a plasticizing agent. GG-Gly films were investigated as potential systems for buccal drug delivery using fluconazole (Class I of the Biopharmaceutical Classification System) as a model drug. At a low concentration of Gly drug precipitation occurred while, for higher concentrations of Gly, a significant deterioration of mucoadhesive and mechanical properties was observed. One possible way to overcome all these problems could be the addition of hydroxypropyl-β-cyclodextrin (HP-β-CD) to the GG-Gly formulation as a drug-precipitation inhibitor. In this work the effect of cyclodextrin addition on the mechanical, mucoadhesive, swelling and release properties of GG-Gly films was investigated. In-vitro drug release studies were carried out using the paddle type dissolution apparatus (USP II) and the millifluidic flow-through device (MFTD). A moving-boundary model for swelling dynamics and release in USP II is proposed to estimate the effective diffusivity of the solvent, HP-β-CD, fluconazole and complex fluconazole/HP-β-CD in the swelling film. Experimental results, supported by theoretical modeling, confirmed that gellan gum-low glycerol thin films including HP-β-CD represent a suitable formulation for fluconazole drug delivery. A sustained release was observed when GG-Gly film is loaded with a preformed complex fluconazole/HP-β-CD.

Polymeric precipitation inhibitor as an effective trigger to convert supersaturated into supersaturable state in vivo

The supersaturated state of the drug in vivo is thermodynamically unstable resulting in a delayed response and reduced efficacy. The use of polymeric precipitation inhibitor (PPI) has been demonstrated as an effective trigger for the conversion of supersaturated state to supersaturable state for improving solubilization, thermodynamic maintenance of drug concentration and oral absorption of poorly water-soluble compounds. PPI retards drug precipitation and provides a kinetically stabilized supersaturation state for an extended period in gastric and intestinal fluids. However, the selection of appropriate PPI and understanding its mechanism is a challenge for formulating a stable pharmaceutical formulation. The present review is aimed at understanding the intricacies of selecting PPIs and their applications in pharmaceutical formulations.

SOLUBILITY ENHANCEMENT OF GLIBENCLAMIDE USING MESOPOROUS SILICA

Glibenclamide is a BCS Class II drug and poses a major problem during formulation development. In the present study, adsorption onto various carriers was used to enhance the solubility of glibenclamide. It was observed that solubility of glibenclamide was greatly enhanced by adsorbing onto mesoporous silica. The increase in solubility of poorly soluble drugs is often associated with the generation of supersaturation, which results in the risk of drug precipitation. HPMC E5 was used as precipitation inhibitor to maintain sink condition for a longer duration. A 32 full factorial design was adopted to optimize the ratio of glibenclamide (X1) and mesoporous silica as a carrier (X2) and the effect of different ratios was studied on percent yield, percent drug loading, and percent drug release. X-ray powder diffraction (XRPD) and Differential scanning calorimetry studies were performed to investigate any possible interaction in between glibenclamide and mesoporous silica. An optimum batch of drug adsorbate was used to prepare immediate-release tablets. The tablets prepared were evaluated for thickness, uniformity of weight, hardness, friability, in-vitro disintegration time, and in vitro drug release study.

Efficacy of management for obstruction caused by precipitated medication or lipids in central venous access devices: A systematic review and meta-analysis

At present, central venous access devices (CVADs) are widely used in clinical practice. The reasons for CVAD obstruction caused by precipitated medication or lipids are increasingly complex. However, there is no clear treatment program for CVAD obstruction caused by precipitated medication or lipids. The target of this study was to analyze data regarding obstruction caused by precipitated medication or lipids in CVADs and to calculate the efficacy of different treatment methods. A systematic review with meta-analysis was conducted in alignment with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. The PubMed, Web of Science, EMBASE, Cochrane Library, CINAHL, and China National Knowledge Internet databases were searched for original research published before 2018. There were 1356 publications initially screened, with one additional study identified through snowballing. Seven studies met the inclusion criteria. The reasons for obstruction, except for clot formation, primarily included the following: mechanical complications; lipid deposition; mineral deposition; or drug precipitation. Meta-analysis showed that sodium hydroxide resulted in the highest recanalization rate in lipid deposition, followed by ethanol, and the difference was significant. The efficacy analysis revealed that hydrochloric acid and l-cysteine have similar effects on mineral deposition and drug precipitation. According to this review, the most effective methodology was shown to be the intravenous perfusion of sodium hydroxide in several treatments when the obstruction is caused by lipid deposition. In contrast, mineral deposition and drug deposition are best treated with l-cysteine to recover the patency of central venous access devices.

EFFECT OF PHYSICOCHEMICAL PROPERTIES OF EMULSIONS FORMED BY SELF-EMULSIFYING DRUG DELIVERY SYSTEMS (SEDDS) ON THE SOLUBILIZATION STATE OF DRUG: IN VITRO STUDY

Objective: Parameters in the oil pre-concentrate which can affect the solvent capacity of the resultant dispersion such as, oil-cosurfactant ratio, type of surfactant used in the system, the inclusion of water soluble co-solvents and the solubilization capacity of native surfactants such as, bile salts and lecithin were studied in an attempt to circumvent crystallization of drug during its passage in the gut.Methods: Different types of self-emulsifying systems representing type II, IIIA and IIIB, were used to probe the influence of the various physicochemical properties of the resultant dispersions on the fate of dissolved model lipophilic drug. This was achieved by studying emulsification behavior of lipid systems in fed and fasted biological fluids, analyzing solubilization/drug crystallization kinetics and oil droplet diameter measurement.Results: Self-micro-emulsifying lipid systems lost solvent capacity on dispersion and were not able to keep the drug in solution at equilibrium. Miglyol 812/Imwitor ratio in the pre-concentrate mixture appeared to influence the kinetics of drug crystallization. Pre-microemulsion systems containing Tagat TO dispersions were found to hold more drugs in solution at equilibrium than in the case of systems containing Cremophor RH40. The inclusion of as little as 10-20% PEG in the lipid mixture accelerated drug precipitation. Bile salt-lecithin mixed micelles appears to some extent enhance the solubilization capacity of these systems after dispersionConclusion: Solvency of emulsions formed by self-emulsifying drug delivery in various emulsification media is a crucial parameter influencing the fate of dissolved drug after the dispersion of the formulations.