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I Peksoy

Publications and source records attributed to I Peksoy.

12 recordsLinked to original sources
PubMed2000

Diclofenac sodium incorporated PLGA (50:50) microspheres: formulation considerations and in vitro/in vivo evaluation.

Recently, considerable interest has been focused on the use of biodegradable polymers for specialized applications such as controlled release of drug formulations; meanwhile, microsphere drug-delivery systems using various kinds of biodegradable polymers have been studied extensively during the past two decades. Poly (lactide-co-glycolide) (PLGA) polymers have been proven to be excellent drug carriers for microparticulate systems due to their advantages, e.g. biocompatibility and regulatory approval. The administration of nonsteroidal anti-inflammatory drugs (NSAIDs) into the intra-articular cavity in patients with chronic inflammatory disease is complicated due to the short duration of effect. In the present study, controlled-release parenteral formulations of diclofenac sodium (DS), a commonly used NSAID, were prepared for intra-articular administration, and evaluated in vitro for particle size, yield, drug loading, surface morphology and release characteristics. For in vivo studies, Technetium-99m labelled polyclonal human immunogammaglobulin (99m Tc-HIG) was used as the radiopharmaceutical to demonstrate arthritic lesions by gamma scintigraphy. Evaluation of arthritic lesions post-therapy in rabbits showed no significant difference in the group treated with PLGA (50:50) (mw 34000) DS microspheres compared to control groups.

Animals↗
PubMed1999

Prediction of response to revascularization in patients with renal artery stenosis by Tc-99m-ethylenedicysteine captopril scintigraphy.

The aim of the present study was to assess the predictive value of captopril scintigraphy with the new renal agent 99mTc-ethylenedicysteine (99mTc-EC) for post-interventional improvement in blood pressure. Twelve patients who had persistently high blood pressure with previous demonstration of various degrees of renal artery lesion on angiography were included into the study. Baseline and captopril scintigraphies were performed on the same day at 4 hour intervals after the injection of 74 and 296 MBq of 99mTc-EC, respectively. All patients had percutaneous transluminal angioplasty (PTA), and improvement in blood pressure was evaluated 3-6 months after the intervention. 99mTc-EC captopril scintigraphy successfully predicted a positive or negative outcome in 11 of 12 patients. In one patient with captopril induced renal function deterioration, scintigraphy failed to predict post-interventional response. Our preliminary findings showed that 99mTc-EC captopril scintigraphy can be used to determine patients who will benefit from revascularization.

Adult↗
PubMed1999

Technetium-99m pertechnetate uptake in ectopic parathyroid adenoma.

A 37-year-old male with a persistent increased parathyroid hormone level, after subtotal thyroidectomy and parathyroidectomy, was referred for scintigraphic localization of a possible ectopic parathyroid adenoma. Tc-99m pertechnetate and Tc-99m MIBI scintigraphy were performed on separate days. There was marked uptake of both tracers in the mediastinum, which at surgery was confirmed to be an extrathyroidal parathyroid adenoma. Hypervascularity was suggested as a possible explanation for rare cases of pertechnetate avid parathyroid adenomas. And Tc-99m MIBI scintigraphy proved to be a successful imaging procedure for ectopic parathyroid tissue.

Adenoma↗
PubMed1999

Comparison of Tc-99m EC and Tc-99m DTPA captopril scintigraphy to diagnose renal artery stenosis.

PURPOSE: Although, captopril scintigraphy is a well established method to detect renovascular hypertension, the optimal radiopharmaceutical for this test remains to be determined. Recently, Tc-99m ethylenedicysteine (Tc-99m EC) appeared as an alternative agent for captopril scintigraphy. The aim of this study was to compare the diagnostic accuracy of Tc-99m EC with Tc-99m DTPA, which is a well-established renal radiopharmaceutical for the captopril test. METHODS: Nineteen hypertensive patients who had various degrees of renal artery stenosis on angiography were included in the study. All patients had baseline and captopril Tc-99m EC and Tc-99m DTPA scintigraphy within a 1-week period. The results were compared with angiography and in eight patients with changes in blood pressure after revascularization. The images were interpreted without knowledge of the angiography and revascularization data as low, intermediate, or high probability for hemodynamically significant renal artery stenosis, which was defined as an area of stenosis exceeding 50%. RESULTS: Tc-99m EC and Tc-99m DTPA study results were in agreement in 16 of the 19 patients. In two patients with branch artery stenosis, Tc-99m EC was definitely superior to Tc-99m DTPA and correctly identified the probability of stenosis on scintigraphy. On kidney analysis, Tc-99m EC had a slightly greater diagnostic sensitivity compared with Tc-99m DTPA (79% vs. 68%; P > 0.05 by the chi-squared test) but equal specificity (93% for both agents). Both Tc-99m EC and Tc-99m DTPA showed the same accuracy in predicting the outcome after revascularization in all but one patient with branch artery stenosis, in whom Tc-99m EC accurately predicted a successful outcome of the intervention but Tc-99m DTPA did not. Tc-99m EC had better renal uptake in patients with decreased renal function and provided more dramatic evidence of renogram changes after captopril intervention, which resulted in more confident interpretation. CONCLUSIONS: There is no significant difference between Tc-99m EC and Tc-99m DTPA captopril scintigraphy for detecting renal artery stenosis. However, because of the better imaging characteristics and more confident interpretation provided by the dramatic changes in the degree of renogram abnormality after captopril intervention, Tc-99m EC captopril scintigraphy should be used, particularly in patients with decreased renal function or branch artery stenosis.

Adult↗
PubMed1996

Evaluation of Tc-99m(V) DMSA for imaging inflammatory lesions: an experimental study.

The present study evaluated 99mTc(V) DMSA as an agent for the visualization of inflammatory lesions in comparison to 99mTc(III) DMSA and 99mTC-HIG. All three radiopharmaceuticals were prepared with commercial kits. 99mTc(V) DMSA was prepared at neutral pH by the addition of first bicarbonate and then pertechnetate to the kit contents. The labeling efficiency was 99% as determined by ITLC. Abscesses were induced by i.m. injection of 50 microliters turpentine into the right thighs of 36 Swiss albino mice. Six days later 3.7 MBq of each radiopharmaceutical was i.v. administered to 12 mice. The mice were sacrificed at 1, 3, 6 and 24 h later. Scintigrams were obtained with a gamma camera. The abscesses were better visualized on scintigrams with 99mTc(V) DMSA compared to 99mTc(III) DMSA, starting at 1 h. The animals were dissected and the organs were removed, weighed and the radioactivity determined with a gamma counter. The abscess to other tissue ratios were higher with 99mTc(V) DMSA than the other radiopharmaceuticals. The max. abscess/muscle ratios were 9.46 +/- 3.20 (24 h), 4.19 +/- 1.39 (6 h) and 5.98 +/- 1.17 (24 h) and max. abscess/blood ratios were 6.22 +/- 1.41, 4.09 +/- 0.84 and 0.914 +/- 0.351 all at 24 h for 99mTc(V) DMSA, 99mTc(III) DMSA and 99mTc-HIG, respectively. Experimental arthritis was produced in New Zealand white rabbits by intra-articular injection of ovalbumin. Four days later 37 MBq of 99mTc(V) DMSA and 99mTc-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h clearly demonstrated arthritic joints. ROI's over arthritic joints were compared to contralateral normal joints (A/C). The max. A/C ratios were 2.10 +/- 0.31 (3 h) and 2.92 +/- 0.99 (24 h) for 99mTc(V) DMSA and 99mTc-HIG, respectively. Our results indicated the feasibility of imaging inflammatory lesions with 99mTc(V) DMSA.

Abscess↗
PubMed1996

Renovascular hypertension due to Takayasu's arteritis demonstrated by Tc-99m ethylenedicysteine captopril scintigraphy.

A 34-year-old woman with severe hypertension underwent Tc-99m ethylenedicycteine (Tc-99m EC) captopril renal scintigraphy. There was bilateral parenchymal retention of the tracer suggesting renal artery stenosis. Angiography confirmed bilateral renal artery stenosis and also demonstrated contour irregularities of the abdominal aorta, and stenosis in mesenteric and subclavian arteries with increased collateral circulation consistent with Takayasu's arteritis. In light of this case of renal artery stenosis, it was concluded that Tc-99m EC can be used successfully as a potential renal agent in the diagnosis of renal involvement in patients with Takayasu's arteritis.

Adult↗
PubMedDate not supplied

In vitro evaluation and intra-articular administration of biodegradable microspheres containing naproxen sodium.

The dispersion of non-steroidal antiinflammatory drugs (NSAIDs) into biodegradable polymeric matrices have been accepted as a good approach for obtaining a therapeutic effect in a predetermined period of time meanwhile minimizing the side effects of NSAIDs. In the present study, it was aimed to prepare Naproxen Sodium (NS), (a NSAID) loaded microsphere formulation using natural Bovine Serum Albumin (BSA) and synthetic biodegradable polymers such as poly(lactide-co-glycolic acid) (PLGA) (50:50 MW 34,000 and 88,000 Da) for intra-articular administration, and to study the retention of the drug at the site of injection in the knee joint. NS incorporated microspheres were evaluated in vitro for particle size (the mean particle size; for BSA microspheres, 10.0 +/- 0.3 microm, for PLGA microspheres, 9.0 +/- 0.2 and 5.0 +/- 0.1 microm for MW 34,000 and 88,000 Da, respectively), yield value, drug loading, surface morphology and drug release. For in vivo studies, monoarticular arthritis was induced in the left knee joints of rabbits by using ovalbumin and Freund's Complete Adjuvant as antigen and adjuvant. A certain time (4 days) is allowed for the formation of arthritis in the knee joints, then the NS loaded microspheres were injected directly into the articular cavity. At specific time points, gamma scintigrams were obtained to determine the residence time of the microspheres in knee joints, in order to determine the most suitable formulation. This study indicated that PLGA, a synthetic polymer, is more promising than the natural type BSA microspheres for an effective cure of mono-articular arthritis in rabbits.

Animals↗
PubMedDate not supplied

In vitro and in vivo evaluation of diclofenac sodium loaded albumin microspheres.

The use of polymeric carriers in formulations of therapeutic drug delivery systems has gained widespread application, due to their advantage of being biodegradable and biocompatible. Among the microparticulate systems, microspheres have a special importance since it is possible to target drugs and provide controlled release. Diclofenac sodium (DS), is a potent drug in the NSAID group having non-steroidal, anti-inflammatory properties, and is widely used in the treatment of rheumatoid arthritis, osteoarthritis and ankylosing spondylitis. In this present study, it was aimed to prepare microsphere formulations of DS using a natural biodegradable polymer as a carrier for intraarticular administration to extend the duration period of the dosage form in the knee joint. Microsphere formulations of DS which were prepared were evaluated in vitro for particle size, yield value, encapsulation efficiency, surface morphology, and in vitro drug release. Two appropriate formulations were selected for in vivo trials. For the in vivo studies, Technetium-99m labelled polyclonal human immunogammaglobulin (99mTc-HIG) was used as the radiopharmaceutical to demonstrate arthritic lesions by gamma scintigraphy. After the induction of arthritis in knee joints of rabbits, the radio-labelled microspheres loaded with DS were injected directly into the articular cavity and at specific time points gamma scintigrams were obtained to find the residence time of the microspheres in knee joints in order to determine the most suitable formulation.

Animals↗