Pharmaceutical Nanotechnology (v.3, #3)

Editorial by Ijeoma Uchegbu (153-153).

Gold Nanoparticles as Carrier(s) for Drug Targeting and Imaging by Satish Shilpi, Kapil Khatri (154-170).
Nanotechnology has been explored for its prospective to deliver bioactives in potentially safer concentrations through both passive and active targeting. Inorganic nanomaterials particularly gold nanoparticles find tremendous applications in biomedicine. In this review, common synthesis techniques and biofunctionalization strategies and areas of applications for gold nanoparticles are discussed. Gold nanoparticles can be considered as advanced platforms for combined therapeutic and diagonostic applications due to their unique physicochemical properties including large specific surface area, adaptability to surface modification, biocompatibility and stability. Further they possess photothermal and radiosensitization characteristics. Gold nanoparticles possess unique properties in terms of their use in drug delivery, therapeutic, biodiagonostics and imaging applications.

Polymeric Micelles for Ocular Delivery: Progress and Issues by Nida Akhtar, Kamla Pathak (171-187).
Background: Polymeric micelles are nano -sized systems formed spontaneously in aqueous milieu through the self-assembly of GRAS listed/FDA approved polymeric surfactants. Development of polymeric micelles for ocular drug delivery has gained tremendous scientific interest owing to the fact that the drug-vehicle features affect the potentiality of site-specific transport of therapeutic actives. Objective: The present article highlights the therapeutic potential polymeric micelles as a drug delivery carrier in enhancing the retention and permeation at ocular site, thus, improvising the drug absorption. Considerable deliberations have been made to highlight the preclinical studies conducted so far on polymeric micelles depicting their importance in ocular delivery. Beneficial characteristics of polymeric micelles include development of environmentallyseparated system drugs via supramolecular assembly, installing therapeutically active substance on the surface, prolonged retention and stability. Various issues related to the usage of these have also been discussed followed by the clinical progress of the carrier. Despite the fact that polymeric micelles have demonstrated eminent preclinical outcomes, very few have been reached to clinical status and reported to be available in the market. Clinical trials of certain formulations are in progress. Conclusion: The nanosized delivery systems are efficient carrier systems that can be used for targeting the drug to both anterior and posterior ocular segments. As a non invasive method the polymeric micelles have tremendous therapeutic efficacy in targeting posterior ocular tissues thus, fulfilling the need for ophthalmic implications.

Solid Lipid Nanospheres for Atrovastatin calcium: Formulation Design, optimization and Drug Release Dynamics by Mukesh Sharma, Vidhi Shah, Radhika Pandya, Rajesh K. Parikh, Bhavesh Bharatiya, B. N. Suhagia, Atindra D. Shukla (188-204).
Objective: Present work highlights a strategy to employ solid lipid nanoparticles (SLNs) to encapsulte Atorvastatin calcium (BCS II), which shows low oral bioavailability due to its poor aqueous solubility.
Method: Spherical solid lipid nanoparticles containing atorvastatin calcium were formulated by solvent injection technique and characterized for their size and morphology, entrapment efficiency, stability studies, and drug release dynamics. Factorial design was employed to optimize manufacturing conditions of SLNs using two variables, amount of lipid and amount of surfactant.
Result: Entrapment efficiency of the Atorvastatin calcium loaded SLNs were modeled statistically to attain maximum entrapment efficiency. The drug release behaviour of the optimized formulation F7 was studied in dissolution media and 59% of the atorvastatin calcium from SLN was gradually released during 24 h, which showed efficient sustained release of the drug. In vivo studies on rats indicate oral bioavailability of atorvastatin calcium from spherical SLN was enhanced by 2.74 folds compared to free atorvastatin calcium. After 90 days of storage, >97% ATC remained intact thus the stability of drug was substantially improved by incorporation in to SLN.
Conclusion: These results successfully demonstrate that SLN as a drug delivery vehicle fulfills prolonged release formulation for low bioavailable drugs as well as offers a novel approach to improve oral bioavailability of poorly soluble drugs.

Background: Polyphenols are promising drug candidates because of their multifaceted properties such as anti-cancer, anti-diabetic, anti-oxidant, etc. However, their potential has not been fully exploited because of their poor solubility and bioavailability. Objective: The objective of this study was to investigate the application of nanoprecipitation as a plausible means for enhancing the solubility and dissolution of chrysin employing Tween 80 as stabilizer. Methods: The effect of various process parameters such as drug concentration, stirring speed, base:acid ratio and flow rate on the particle size and solubility of chrysin nanocrystals were determined. The formulated nanoparticles were evaluated for in vitro dissolution studies and anti-inflammatory activity. Results: A minimum particle size of 150 nm was obtained for chrysin nanocrystals when drug concentration was 5 mg/ml, stirring speed 4500 rpm, base:acid ratio 0.1:1 and flow rate was 10 ml/min. The aqueous solubility of chrysin nanoparticles was enhanced to 1.12 ?g/ml as compared to pure chrysin which was found to be 0.04 ?g/ml. The results of in vitro dissolution studies showed enhanced dissolution of chrysin from nanoparticles (95%). Furthermore, the chrysin nanoparticles exhibited a higher free radical scavenging activity (70%). The % inhibition of rat paw edema observed with chrysin nanoparticles was 43% whereas it was only 28% with pure chrysin. Conclusion: These findings highlight the application of nanotechnology for solubility enhancement of chrysin, a polyphenol with colossal therapeutic potential.