Ameliorating the antitumor activity of lenalidomide using PLGA nanoparticles for the treatment of multiple myeloma

Abstract Lenalidomide (LND) is an anti-cancer drug and an effective derivative of thalidomide used for multiple myeloma therapy. Because of its poor solubility in water, LND is known to cause low oral bioavailability (below 33%), and as a direct consequence of this, the dosing frequency is extended thus increasing risk of toxicity. To improve its bioavailability and sustained release, the present study aims to formulate polymeric nanoparticles (NPs) for LND using [Poly (lactic-co-glycolic acid)] (PLGA) as a polymer. The polymeric NPs were evaluated for particle size, SEM, XRD, drug content, entrapment efficiency (EE), in vitro release studies and in vivo bioavailability studies in rats. The formulated NPs possessed a size of 179±0.9 nm and a zeta potential of -24.4 ± 0.2 mV. The drug loading and EE of the optimized formulation was 32 ± 0.37 % and 78 ± 0.92% respectively. After oral administration of LND PLGA-NPs, the relative bioavailability was enhanced about 3.67-fold compared to LND. This study demonstrates the novel drug delivery for LND with PLGA-NPs as effective drug delivery system for sustained delivery of LND.

Curcumin loaded chitosan nanoparticles impregnated into collagen-alginate scaffolds for diabetic wound healing.

Diabetic wounds are a common complication in patients with diabetes that often lead to amputation. Although the pathophysiology of diabetic wound is multifactorial, chronic inflammation and lack of tissue regeneration leads to impair wound healing in diabetes. Application of curcumin (CUR) which is a well-known anti-inflammatory and antioxidant agent could be better strategy in diabetic wound healing. However, low bioavailability and poor stability of CUR hinders its application. Hence, in present study a novel nanohybrid scaffold has been prepared by incorporating CUR in chitosan nanoparticles (CSNPs) to improve stability and solubility followed by impregnation of prepared CUR-CSNPs into collagen scaffold (nanohybrid scaffold) for better tissue regeneration application. The prepared CUR-CSNPs were evaluated for particle size, zeta potential, SEM, differential scanning calorimetry and X-ray powder diffraction studies and the novel nanohybrid is evaluated for morphology, biodegradability, biocompatibility, in vitro drug release and in vivo wound healing studies. The results of NPs evaluation suggest the better stability and solubility of CUR. The nanohybrid scaffold showed good in vitro characteristics in terms of better water uptake, biocompatibility and sustained drug availability. The results of in vivo wound closure analysis revealed that nanohybrid scaffold treated wounds contracted significantly (p<0.001) faster than the wounds from the control and placebo scaffold groups. Further, the obtained results suggest that complete epithelialization with thick granulation tissue formation occur in nanohybrid scaffold group, whereas lack of compact collagen deposition in placebo scaffold group and presence of inflammatory cells in control group was observed. Hence, the present study suggests that the synergistic combination of CUR (anti-inflammatory and anti-oxidant), chitosan (sustain drug carrier, wound healing) and collagen (established wound healer as scaffold) is a promising strategy to address various pathological manifestations of diabetic wounds and have better wound healing capability.

Simultaneous enantioseparation and purity determination of chiral switches of amlodipine and atenolol by liquid chromatography.

A novel, selective and robust enantiospecific HPLC method was developed for simultaneous determination of amlodipine and atenolol enantiomers. Box-Behnken design was employed to identify the effect of factors (% ethanol, % diethylamine and flow rate) and their interactions on enantioresolution and analysis time. Chromatography was performed using mobile phase comprising acetonitrile, ethanol and DEA (92:8:0.2% v/v/v) delivered at a flow rate of 1.2mLmin(-1) on a Lux Cellulose-4 column. The enantiomers were monitored at a wavelength of 240nm and separation was achieved within 8min. The method was validated in terms of specificity, linearity, accuracy, precision, limit of detection and quantification. The method was found to be linear (R(2)≥0.991), accurate (99.8-101.4%) and precise (%RSD≤3%). Additionally, fractional factorial design was used to evaluate the robustness of the method and non-significant intervals for mixture related factors were established using contour profiling. Furthermore, the pertinence of this validated method was established by analyzing three different commercially available formulations. The obtained results confirmed that the proposed method can be extended for routine enantiopurity assay of amlodipine and atenolol in pharmaceutical formulations.

Multiple response optimization of a liquid chromatographic method for determination of fluoroquinolone and nitroimidazole antimicrobials in serum and urine.

OBJECTIVES: Development and validation of a sensitive, selective and robust SPE assisted HPLC method for the quantification of fluoroquinolones and nitroimidazoles in human serum and urine using design of experiments methodology. DESIGN AND METHODS: Design of experiments was employed for method optimization (Box-Behnken design) and robustness testing (Plackett-Burman design). Sample preparation involved a simple solid phase extraction, which offered a satisfactory recovery (≥94%). Analytes were separated on a phenyl hexyl column with mobile phase comprising water, acetonitrile and triethyl amine in ratio of 74:26:0.15 v/v, with a flow rate of 1.1mL/min. RESULTS: Calibration curves were linear over selected range (≥0.995) for all the analytes. The method was sensitive with detection limits of 0.06-0.16µg/mL in serum and urine samples. Inter and intra-day precision data (in terms of %RSD) was found to be less than 7%. Stability studies were carried out to assess freeze thaw, short term and long term stability and all analytes were found to be stable. The method was successfully applied for determination of antimicrobial drugs in spiked serum and urine. CONCLUSION: The obtained results corroborated the potential of the proposed method for determination of all the four antimicrobial drugs in therapeutic drug monitoring, bioequivalence and drug-drug interaction studies.

Current and emerging therapies in the management of diabetic foot ulcers.

BACKGROUND: Diabetic foot ulcers are one of the major causes of mortality in diabetic patients. Very few drugs and therapies have regulatory approval for this indication and several agents from diverse pharmacological classes are currently in various phases of clinical trials for the management of diabetic foot ulcers. SCOPE: The purpose of this review is to provide concise information of the drugs and therapies which are approved and present in clinical trials. REVIEW METHODS: This review was carried out by systematic searches of relevant guidelines, patents, published articles, reviews and abstracts in PubMed/Medline, Web of Science, clinicaltrials.gov, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Google Scholar of all English language articles up to 1 March 2015. The following search terms were used: diabetes, diabetic foot, diabetic foot ulcer, diabetic wound, diabetic foot infections, wound management, randomized controlled trials, approved treatments, new treatments and clinical trials. CONCLUSIONS: The various drugs and therapies for the management of diabetic foot ulcers comprise antibiotics, neuropathic drugs, wound dressings, skin substitutes, growth factors and inflammatory modulators. The majority of these therapies target the treatment of diabetic foot ulcers to address the altered biochemical composition of the diabetic wound. However, no single treatment can be definitively recommended for the treatment of diabetic foot ulcers.

Fabrication and in vivo evaluation of Nelfinavir loaded PLGA nanoparticles for enhancing oral bioavailability and therapeutic effect.

Nelfinavir mesylate (NFV) is an anti-viral drug, used in the treatment of Acquired Immunodeficiency Syndrome (AIDS). Poor oral bioavailability and shorter half-life (3.5-5 h) remain a major clinical limitation of NFV leading to unpredictable drug bioavailability and frequent dosing. In this context, the objective of the present study was to formulate NFV loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), which can increase the solubility and oral bioavailability along with sustained release of the drug. NFV loaded PLGA-NPs were prepared by nanoprecipitation method using PLGA and Poloxomer 407. The prepared NPs were evaluated for particle size, zeta potential, morphology, drug content, entrapment efficiency (EE) and in vitro dissolution studies. Oral bioavailability studies were carried out in New Zealand rabbits by administering developed NFV PLGA-NPs and pure drug suspension. PLGA-NPs prepared by using 1:4 ratio of drug and PLGA, with a stirring rate of 1500 rpm for 4 h. The prepared NPs were in the size of 185 ± 0.83 nm with a zeta potential of 28.7 ± 0.09 mV. The developed NPs were found to be spherical with uniform size distribution. The drug content and EE of the optimized formulation were found to be 36 ± 0.19% and 72 ± 0.47% respectively. After oral administration of NFV PLGA-NPs, the relative bioavailability was enhanced about 4.94 fold compared to NFV suspension as a control. The results describe an effective strategy for oral delivery of NFV loaded PLGA NPs that helps in enhancing bioavailability and reduce the frequency of dosing.

Systematic Robustness Testing of a Liquid Chromatographic Method: A Case Study.

Robustness testing of a method plays a crucial role in establishing its reliability. It examines the potential sources of variability in one or more responses of the proposed method. In this study, the robustness testing of a method proposed for simultaneous determination of warfarin and its two process related impurities was evaluated by using two level, fractional factorial design. Factors that are sensitive to a variation during method transfer were selected as independent variables [aqueous content (range: 39-43%, v/v), concentration of acetic acid (range: 0.08-0.12%, v/v), flow rate (range: 0.93-1.33 mL/min), and wavelength (range: 218-222 nm)]. Variables that determine the quality of separation, viz., retention factor of the first peak, resolution between the critical peak pair, tailing factor of warfarin, and total analysis time were selected as responses. Robustness was assessed by graphical (half normal probability and Pareto plots) and statistical (analysis of variance) methods. It was found that, among the studied variables, aqueous content had a significant effect on capacity factor and analysis time. Furthermore, non-significant intervals for significant factors were established by contour profiling. This study demonstrated the significance of experimental design and other statistical tools in understanding the effects of investigating factors of the chromatographic system and in defining their limits.

Development and validation of a generic liquid chromatographic method for the simultaneous determination of five commonly used antimalarial drugs: Application to pharmaceutical formulations and human plasma.

A simple, sensitive, and rapid liquid chromatographic method was developed and validated using diode array detection for the determination of five commonly used antimalarial drugs in pharmaceutical formulations and in human plasma. Chromatographic separation of antimalarial drugs and internal standard (ibuprofen) was achieved on a C18 column with a mobile phase composed of 10 mM dipotassium orthophosphate at pH 3.0, methanol, and acetonitrile in a ratio of 20:38:42 v/v, at a flow rate of 1 mL/min. The analytes were monitored at 220 nm and separated in ˂10 min. The method was validated for linearity, accuracy, precision, limit of quantification, and robustness. Both intra- and interday precisions (in terms of %RSD) were lower than 3% and accuracy ranged from 98.1 to 104.5%. Extraction recoveries were ≥96% in plasma. The limits of quantitation for artemether, lumefantrine, pyrimethamine, sulfadoxine, and mefloquine were 0.3, 0.03, 0.06, 0.15, and 0.15 µg/mL in human plasma. Stability under various conditions was also investigated. The method was successfully applied for quantification of antimalarial drugs in marketed formulations and in spiked human plasma. The method can be employed for routine QC purposes and in pharmacokinetic investigations.

Development and validation of a HPLC-PDA bioanalytical method for the simultaneous estimation of Aliskiren and Amlodipine in human plasma.

A simple, unique and selective HPLC-PDA method was developed and validated for the simultaneous estimation of aliskiren (ALS) and amlodipine (AML) in human plasma. Extraction of the sample was accomplished by protein precipitation. Plasma proteins were precipitated by employing acetonitrile containing hydrochlorothiazide as internal standard. The compounds were analyzed by HPLC by using PDA detector on a Hibar C18 (250 × 4.6 mm) column with a mobile phase comprising acetonitrile and phosphate buffer (pH 4.2 and 25 mm; 60:40 v/v) with a flow rate of 0.8 mL/min. Different sample pretreatment techniques were evaluated but protein precipitation was found to be satisfactory, offering good recovery values of 97.11-98.45% for ALS and 97.5-99.12% for AML. The within-day precisions for ALS were 96.66, 99.16 and 99.41% at 90, 240 and 480 ng/mL, respectively, and for AML they were 97.27, 99.54 and 99.31% at 3.3, 8.8 and 17.6 ng/mL, respectively. The between-day precisions for ALS were 96.66, 99.16 and 99.41% at 90, 240 and 480 ng/mL, respectively and the between-day precisions for AML were 98.18, 99.20 and 99.40% at 3.3, 8.8 and 17.6 ng/mL, respectively. The limit of quantitation was 30 and 1.0 ng/mL for ALS and AML respectively. Different constituents of plasma proteins did not interfere with the absolute recovery of ALS and AML.

Stability-Indicating HPLC Method for the Simultaneous Determination of HIV Tablet Containing Emtricitabine, Tenofovir Disoproxil Fumarate, and Rilpivirine Hydrochloride in Pharmaceutical Dosage Forms.

A simple, accurate, rapid, and stability-indicating RP-HPLC method for a combination of tenofovir disoproxil fumarate, emtricitabine, and rilpivirine has been developed and subsequently validated in commercial tablets. The proposed HPLC method utilizes Phenomenex Gemini C18 column (150 mm × 4.6 mm i.d., 5 µm) and mobile phase consisting of MeCN, potassium dihydrogen phosphate buffer (20 mM, pH 3.3), and triethylamine 58.72 : 41.23 : 0.05 (v/v) at a flow rate of 1.7 mL/min. Quantitation was achieved with UV detection at 270 nm. The method was validated in terms of accuracy, precision, linearity, limits of detection, limits of quantitation, and robustness. This optimized method has been successively applied to pharmaceutical formulation and no interference from the tablet excipients was found. TDF, EMT, and RPV and their combination drug product were subjected to acid, base, neutral hydrolysis, oxidation, dry heat, and photolytic stress conditions and the stressed samples were analyzed by the proposed method. As the proposed LC method could effectively separate the drugs from its degradation products, it can be employed as stability-indicating method for the determination of instability of these drugs in bulk and commercial tablets.