Shape mediated splenotropic delivery of buparvaquone loaded solid lipid nanoparticles.

Buparvaquone (BPQ)-loaded asymmetric solid lipid nanoparticles (SLN) prepared by a modified nanoprecipitation method were evaluated for splenotropic drug delivery. BPQ SLN exhibited an average particle size of 650.28 ± 6.75 nm with polydispersity index ≤ 0.3, entrapment efficiency of 96.57 ± 0.190%, and drug loading of 24.63 ± 0.042%. Scanning electron microscopy (SEM) revealed elongated particles with flattened and rounded edges. Aspect ratio, an important determinant of asymmetricity of the BPQ SLN, measured as the ratio of average length (1143 ± 0.083 nm) to width (419 ± 0.031 nm) was found to be 2.727 ± 0.19. The hemolytic potential of 10.86 ± 0.04% and good serum stability suggested feasibility for intravenous administration. 99mTc-labeled BPQ SLN revealed high radiolabeling efficiency (> 95%) and good stability. Intravenous administration in mice revealed > 75% accumulation in the reticuloendothelial system organs. The percent radioactivity per gram of organ was in the order spleen > kidney > lungs > liver > lymph nodes, with high splenic accumulation and significantly lower concentration in the liver. An astoundingly high spleen/liver ratio with a maximum of 11.94 ± 1.37 at 3 h, which confirmed high splenic uptake is attributed to Kupffer cell bypass. Other factors contributing to splenotropy are the rigidity and the low molecular weight of the lipid in the BPQ SLN which enabled translocation of the particles into the splenic pulp. Our study proposes asymmetric BPQ SLN as a promising splenotropic delivery system for improved efficacy in theileriosis, a spleen resident infection.

A coupled bimodal SPECT-CT imaging and brain kinetics studies of zolmitriptan-encapsulated nanostructured polymeric carriers.

The present investigation deals with preparation and characterization of anti-migraine zolmitriptan (ZMT) nanostructured polymeric carriers for nose to brain drug targeting. The drug-loaded colloidal nanocarriers of ZMT were prepared by modified ionic gelation of cationic chitosan with anionic sodium tripolyphosphate and characterized for particle size, zeta potential, and entrapment efficiency. Further, in order to investigate nose to brain drug targeting, biodistribution, and brain kinetics studies were performed using 99mtechnetium radiolabeled nanocarriers (99mTc-ZMTNP) in Swiss albino mice. The results were compared with intranasal pure drug solution (99mTc-ZMT) and intravenous nanocarriers (99mTc-ZMTNP). A single photon emission computerized tomography (SPECT) radioimaging studies were also carried out to visualize and confirm brain uptake of nanocarriers. The optimized nanocarriers showed particle size of 161 nm, entrapment efficiency of 80.6%, and zeta potential of + 23.7 mV. The pharmacokinetic parameters, Cmax, and AUC0-∞ values for ZMT concentration in the brain expressed as percent radioactivity per gram of brain in intranasal and intravenous route of administration were calculated. The brain Cmax and AUC0-∞ values found in three groups, intranasal 99mTc-ZMTNP, intranasal 99mTc-ZMT, and intravenous 99mTc-ZMTNP were (0.427 and 1.889), (0.272 and 0.7157), and (0.204 and 0.9333), respectively. The higher Cmax values of intranasal 99mTc-ZMTNP suggests better brain uptake as compared to other routes of administration. The significant higher values of nose to brain targeting parameters namely, drug targeting index (5.57), drug targeting efficiency (557.08%), and nose to brain drug direct transport (82.05%) confirmed drug targeting to brain via nasal route. The coupled bimodal SPECT-CT scintigrams confirm the brain uptake of intranasal 99mTc-ZMTNP demonstrating major radioactivity accumulation in brain. This study conclusively demonstrated the greater uptake of ZMT-loaded nanocarriers by nose to brain drug targeting, which proves promising drug delivery system.

Evaluation of ¹77Lu-EDTMP in Dogs with Spontaneous Tumor Involving Bone: Pharmacokinetics, Dosimetry and Therapeutic Efficacy.

177Lu-EDTMP is currently being investigated as a potential agent for providing palliative care to the patients suffering from bone pain due to metastatic skeletal carcinoma. The present article describes the evaluation of 177Lu-EDTMP complex in four different canine patients with different types of primary and metastatic skeletal lesions with respect to its pharmacokinetic properties, dosimetry and therapeutic efficacy. The dogs were treated with a dose of ~44.4 MBq (1.2 mCi) per kg body weight of 177Lu-EDTMP, synthesized in-house with high radiochemical purity (98.8 ± 0.4 %) and excellent in vitro stability. The radiopharmaceutical showed favourable pharmacokinetic properties, such as, preferential accumulation at skeletal lesion sites and fast clearance from blood and other non-target organs through urinary route. The administered dose of the radiopharmacutical showed excellent therapeutic efficacy in case of a dog suffering from skeletal metastasis originating from primary tumor elsewhere. On the other hand, two of the remaining three patients with primary bone cancer showed stable disease intially with palliative effect. The fourth patient having metal implant induced osteosarcoma with severe limb oedema did not show any response to the treatment.

Liposomes for targeting hepatocellular carcinoma: use of conjugated arabinogalactan as targeting ligand.

Present study investigates the potential of chemically modified (Shah et al., 2013) palmitoylated arabinogalactan (PAG) in guiding liposomal delivery system and targeting asialoglycoprotein receptors (ASGPR) which are expressed in hepatocellular carcinoma (HCC). PAG was incorporated in liposomes during preparation and doxorubicin hydrochloride was actively loaded in preformed liposomes with and without PAG. The liposomal systems with or without PAG were evaluated for in vitro release, in vitro cytotoxicity, in vitro cell uptake on ASGPR(+) cells, in vivo pharmacokinetic study, in vivo biodistribution study, and in vivo efficacy study in immunocompromised mice. The particle size for all the liposomal systems was below 200 nm with a negative zeta potential. Doxorubicin loaded PAG liposomes released significantly higher amount of doxorubicin at pH 5.5 as compared to pH 7.4, providing advantage for targeted tumor therapy. Doxorubicin in PAG liposomes showed superior cytotoxicity on ASGPR(+) HepG2 cells as compared to ASGPR(-), MCF7, A549, and HT29 cells. Superior uptake of doxorubicin loaded PAG liposomes as compared to doxorubicin loaded conventional liposomes was evident in confocal microscopy studies. Higher AUC in pharmacokinetic study and higher deposition in liver was observed for PAG liposomes compared to conventional liposomes. Significantly higher tumor suppression was noted in immunocompromised mice for mice treated with PAG liposomes as compared to the conventional liposomes. Targeting ability and superior activity of PAG liposomes is established pre-clinically suggesting potential of targeted delivery system for improved treatment of HCC.

177Lu-EDTMP: a viable bone pain palliative in skeletal metastasis.

Designing ideal radiopharmaceuticals for use as bone pain palliatives require the use of a moderate energy beta() emitter as a radionuclide and a suitable polyaminophosphonic acid as a carrier molecule. Owing to its suitable decay characteristics [T(1/2) = 6.73 d, E((max)) = 497 keV, E() = 113 keV (6.4%), 208 keV (11%)] as well as the feasibility of large-scale production in adequate specific activity and radionuclidic purity using a moderate flux reactor, 177Lu could be considered as a promising radionuclide for palliative care in painful bone metastasis. The present study was therefore, oriented toward the preparation and biologic evaluation of 177Lu complex of ethylenediaminetetramethylene phosphonic acid (EDTMP) in various animal models, with an aim to prepare a viable radiopharmaceutical for bone pain palliation. 177Lu was produced with a specific activity of approximately 12 GBq/mg (approximately 324 mCi/mg) and radionuclidic purity of 99.98% by irradiation of natural Lu2O3 targeted at a thermal neutron flux of approximately 6 x 10(13) n/cm(2).s for 21 days. 177Lu-EDTMP complex was prepared in high-yield and excellent radiochemical purity (>99%), using EDTMP synthesized and characterized in-house. The complex exhibited excellent in vitro stability at room temperature. Biodistribution studies in Wistar rats showed a rapid skeletal accumulation of injected activity [(1.74 +/- 0.30)% per gram in femur at 3 hours postinjection] with a fast clearance from blood and minimal uptake in any of the major organs. Scintigraphic imaging studies carried out in normal Wistar rats, New Zealand white rabbits, as well as in Beagle dogs also demonstrated significant accumulation of the agent in the skeleton and almost no retention of activity in any other vital organs.

Development of samarium [32P] phosphate colloid for radiosynoviorthesis applications: preparation, biological and preliminary clinical studies experience.

A new therapeutic radio colloid for radiosynoviorthesis (RS) applications is reported. The method of preparation involves the reaction of SmCl3 carrier with carrier added [32P]H3PO4 in the presence of gelatin. The pure colloid was recovered by dialysis purification leading to radiochemical yield of around 90%. The radiochemical purity of the pure colloid formulated in isotonic saline was over 98%, for the usage period of 14 days, as assessed by paper chromatography. Ninety percent of colloid particles were in the size of 1-10 microm as evident from the laser diffraction particle size analysis, ideally suitable for the intended end use. Animal studies revealed complete retention of the radio colloid in the rabbit knee joint. The results of clinical trials in humans are satisfactory and encouraging, satisfactory retention of the colloid in the knee joint and negligible leakage into the systemic circulation.

Target-specific cytotoxic activity of recombinant immunotoxin scFv(MUC1)-ETA on breast carcinoma cells and primary breast tumors.

MUC1 is a mucin family protein, overexpressed in more than 90% of breast cancers in an underglycosylated form, exposing the core peptides of the extracellular domain that act as a potential target for antibody-mediated therapy. We have developed an anti-MUC1 scFv antibody from a phage library of mice immunized with synthetic peptide MUC1-variable number of tandem repeats. MUC1 binding phages were affinity selected through biopanning using a biotin-streptavidin pull-down method. The selected phage clones showed target-specific binding to MUC1-expressing cells. Fusion of truncated Pseudomonas aeruginosa exotoxin A (ETA) to a high binder, phage-derived scFv clone and bacterial expression and purification of recombinant scFv(MUC1)-ETA immunotoxin were done with good yield and purity. In vitro target-specific cytotoxic activity and target-specific binding of immunotoxin were shown on MUC1-expressing cells and primary breast tumor samples. A truncated ETA fusion protein expressed from the same vector but lacking scFv did not show cytotoxic effects, confirming target specificity. Our results suggest that the scFv(MUC1)-ETA immunotoxin has therapeutic potential and deserves further development and characterization for MUC1-specific breast cancers treatment.

Usefulness of (99m)Tc(V)-dimercaptosuccinic acid scintigraphy in the assessment of response to external radiation therapy in soft tissue sarcoma in Giant Snauzer dog.

A nine-year-old male black Giant Schnauzer dog was referred for the scintigraphic evaluation with a history of malignant fibrosarcoma with a rapidly growing non painful mass on the left shoulder region quite near to the site of an operation performed four months ago. We carried out oncological scintigraphy using pentavalent (99m)Technetium labelled dimercaptosuccinic acid [(99m)Tc(V)-DMSA], a tumour localising radiopharmaceutical agent. The study was performed to assess the margins, vascularity of the tumour and response to the cancer therapy. Uniform intense radiopharmaceutical uptake was observed in the lesion indicating its margins, vascularity and malignant nature. The dog was subjected to external radiation therapy to control the growth of the cancer and to bring the tumour mass to an operable size. The dog was followed up with (99m)Tc(V)-DMSA scintigraphy pre-irradiation and post-irradiation. Immediately after the post-irradiation scintigraphy, the dog was operated on. During the surgery, resection of the tumour margins was performed carefully using a hand held gamma probe to assure that no tumour tissue was left inside. In conclusion, the authors would like to state that (99m)Tc(V)-DMSA oncoscintigraphy is valuable in the assessment and evaluation of therapy in canine soft tissue cancer.

Preparation and biological evaluation of 153Sm-DOTMP as a potential agent for bone pain palliation.

BACKGROUND: Designing ideal radiopharmaceuticals for use as bone pain palliative agents requires the use of a moderate energy beta emitter as the radionuclide and a polyaminophosphonic acid as the carrier molecule. Cyclic polyaminophosphonic acid ligands are known for endowing higher thermodynamic stability and kinetic inertness of the radiolabelled agent when complexed with radiolanthanides. AIM: To use Sm (T1/2=46.27 h, Ebeta,max=0.81 MeV, Egamma=103 keV) as the radioisotope, obtainable at an adequate specific activity and high radionuclidic purity by irradiation of a natural Sm2O3 target, and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (DOTMP) as the carrier ligand. RESULTS: The radiolabelling yields under optimized conditions were near quantitative with the additional merit of using a relatively low ligand:metal ratio of 2:1 unlike the 250-fold excess of ligands used in the case of the established agent, Sm-EDTMP. Radiochemical purity was retained with insignificant dissociation on storage up to 10 d at room temperature. Biodistribution studies in Wistar rats demonstrated selective skeletal uptake (4.52%+/-0.49% of injected activity per gram in tibia at 30 min post-injection) with rapid blood clearance and minimal uptake in any of the major organs. No leaching of skeletal activity was observed up to 48 h post-injection. Scintigraphic studies carried out in rabbits also showed significant skeletal accumulation and almost no retention of activity in other vital organs/tissues.

Preliminary studies with 188rhenium-tin colloid for radiation synovectomy: preparation, size determination, in-vivo distribution, effect and dosimetry studies.

BACKGROUND: Generator-produced beta-emitting radionuclides such as (188)Re are gaining in importance for radiosynoviorthesis because of their availability on a regular basis. MATERIAL AND METHODS: We prepared a (188)Re-tin colloid in a reaction carried out either at 100 degrees C or at room temperature (RT). The size of the colloid particles was measured with a laser lightscattering method, and their biodistribution, dosimetric aspects and therapeutic effects were studied in an antigen-induced arthritis (AIA) model in rabbits. (188)Re-tin colloid solution was injected intra-articularly into the knee joints of rabbits with AIA and imaging studies were performed. Blood samples were collected post injection for estimation of the blood residence time. We also injected 2 intact rabbits in the same manner with (188)Re perrhenate solution in order to observe its effects and distribution in the body. All the treated rabbit knees were subjected to histopathology. RESULTS: The colloid particle size distribution was different after preparation at the different reaction temperatures, with a more suitable mean of 4.53 micro m in the RT preparation. The dose delivered to the synovial surface was between 3.51 and 4.21 Gy and that to the bone surface was between 0.70 and 0.84 Gy. Histopathologic examination revealed the development of fibrous connective tissue in the AIA knees 4 weeks after treatment, but not in the control group. CONCLUSIONS: The (188)Re-tin colloid preparation used in this study was suitable for radiation synovectomy application. It requires modifications in the preparation protocol so as to increase the labeling efficiency in correlation with an appropriate particle size.