Lyophilized Nanosuspensions for Oral Bioavailability Improvement of Insoluble Drugs: Preparation, Characterization, and Pharmacokinetic Studies

Lyophilized SLN of Cinnacalcet HCl: BBD enabled optimization, characterization and pharmacokinetic study

Objective: The objective of the present research is to formulate solid lipid nanoparticles (SLN) of CH to improve its oral bioavailability.Methods: Cinnacalcet hydrochloride (CH) exhibits poor oral bioavailability of 20 to 25% because of low aqueous solubility and first pass metabolism. The SLN formulations were optimized using Box-Behnken Design. SLN formulation was prepared using hot homogenization technique followed by ultra-sonication and evaluated. The optimized SLN formulation was lyophilized to improve the stability of the formulation further.Results: Compritol 888 ATO (COM), Soya lecithin (SL) and poloxamer 188 (POL) were selected as lipid, surfactant and co-surfactant respectively. For optimistaion, the desirable goal was fixed for variour responses vis-a-vis entrapment efficiency (EE), particle size (PS) and (time taken for diffusion of 85% drug) T85%. The optimized single dose of SLN obtained using BBD consisting of 30 mg of CH, 100 mg of COM, 150 mg of SL and 0.1% w/v of POL. The pharmacokinetic study revealed that optimized SLN and lyophilized SLN were found to increase the oral bioavailability nearly two times compared to an aqueous suspension of pure drug.Conclusion: Thus lyophilized SLN formulation explicated the potential of lipid-based nanoparticles as a potential carrier in improving the oral delivery and stability of CH.

Bioavailability Enhancement of Poorly Water-Soluble Drugs via Nanocomposites: Formulation⁻Processing Aspects and Challenges

Drug nanoparticles embedded in a dispersant matrix as a secondary phase, i.e., drug-laden nanocomposites, offer a versatile delivery platform for enhancing the dissolution rate and bioavailability of poorly water-soluble drugs. Drug nanoparticles are prepared by top-down, bottom-up, or combinative approaches in the form of nanosuspensions, which are subsequently dried to prepare drug-laden nanocomposites. In this comprehensive review paper, the term “nanocomposites” is used in a broad context to cover drug nanoparticle-laden intermediate products in the form of powders, cakes, and extrudates, which can be incorporated into final oral solid dosages via standard pharmaceutical unit operations, as well as drug nanoparticle-laden strip films. The objective of this paper is to review studies from 2012⁻2017 in the field of drug-laden nanocomposites. After a brief overview of the various approaches used for preparing drug nanoparticles, the review covers drying processes and dispersant formulations used for the production of drug-laden nanocomposites, as well as various characterization methods including quiescent and agitated redispersion tests. Traditional dispersants such as soluble polymers, surfactants, other water-soluble dispersants, and water-insoluble dispersants, as well as novel dispersants such as wet-milled superdisintegrants, are covered. They exhibit various functionalities such as drug nanoparticle stabilization, mitigation of aggregation, formation of nanocomposite matrix⁻film, wettability enhancement, and matrix erosion/disintegration. Major challenges such as nanoparticle aggregation and poor redispersibility that cause inferior dissolution performance of the drug-laden nanocomposites are highlighted. Literature data are analyzed in terms of usage frequency of various drying processes and dispersant classes. We provide some engineering considerations in comparing drying processes, which could account for some of the diverging trends in academia vs. industrial practice. Overall, this review provides rationale and guidance for drying process selection and robust nanocomposite formulation development, with insights into the roles of various classes of dispersants.

Long Acting Ionically Paired Embonate Based Nanocrystals of Donepezil for the Treatment of Alzheimer's Disease: a Proof of Concept Study

PURPOSE

The aim of the present study was to prepare a patient friendly long acting donepezil (D) nanocrystals (NCs) formulation, with a high payload for i.m administration. As the native D hydrochloride salt has high aqueous solubility it is necessary to increase its hydrophobicity prior to the NCs formation.

METHODS

D was ionically paired with embonic acid (E) in aqueous media and was successfully characterized using techniques like DSC, PXRD, FT-IR, NMR etc. Later, we converted the bulk ion pair into NCs using high pressure homogenization technique to study further in-vitro and in-vivo.

RESULTS

The bulk ion pair has a drug content of 66% w/w and an 11,000 reduced solubility in comparison to native D hydrochloride. Also, its crystalline nature was confirmed by DSC and PXRD. The possible interaction sites responsible for the ion pair formation were identified though NMR. The prepared NCs has mean particle size 677.5 ± 72.5 nm and PDI 0.152 ± 0.061. In-vitro release showed a slow dissolution of NCs. Further, excellent bio compatibility of NCs were demonstrated in 3T3 cells. Following i.m administration of single dose of NCs, the D plasma level was found to be detectable up to 18 days. In vivo pharmacodynamic studies revealed that the single dose NCs i.m injection improved spatial memory learning and retention in ICV STZ model.

CONCLUSION

Our results suggest that the developed formulation has a potential to replace the current daily dosing regimen to a less frequent dosing schedule. Graphical Abstract Improved pharmacokinetic and pharmacodynamic profile after administration of single dose donpezil embonate nanocrystals in Rats.