Sprague-Dawley rats bearing McA-RH7777 cells for study of hepatoma and transarterial chemoembolization

AIM

To evaluate the feasibility of the McA-RH7777 tumor model in Sprague-Dawley (SD) rats, for study of hepatoma and transarterial chemoembolization.

MATERIALS AND METHODS

McA-RH7777 rat hepatoma cells (1×10(7)) were inoculated into the left hepatic lobe of SD rats (n=38). Chemoembolization with left common carotid artery access was performed using an emulsion of iodized oil and doxorubicin, and polyvinyl alcohol particles. Tumor induction rate and response to chemoembolization were assessed by magnetic resonance imaging and histology.

RESULTS

Tumor induction rate of McA-RH7777 in SD rat livers was 73.3% (11/15). Hematoxylin-and-eosin staining revealed hypercellular tumor with a trabecular pattern that mimics human hepatocellular carcinoma. Chemoembolization was successfully conducted in all rats. There was a significant difference in tumor growth rates between the chemoembolization-treated and control groups (p<0.0001).

CONCLUSION

A rat tumor model of McA-RH7777 cells in SD rats is feasible and has the potential to be a good model for hepatoma and chemoembolization studies.

Development of ethyl alcohol-precipitated silk sericin/polyvinyl alcohol scaffolds for accelerated healing of full-thickness wounds

Silk sericin has been recently reported for its advantageous biological properties to promote wound healing. In this study, we established that the ethyl alcohol (EtOH) could be used to precipitate sericin and form the stable sericin/polyvinyl alcohol (PVA) scaffolds without the crosslinking. The sericin/PVA scaffolds were fabricated via freeze-drying and subsequently precipitating in various concentrations of EtOH. The EtOH-precipitated sericin/PVA scaffolds showed denser structure, higher compressive modulus, but lower water swelling ability than the non-precipitated scaffolds. Sericin could be released from the EtOH-precipitated sericin/PVA scaffolds in a sustained manner. After cultured with L929 mouse fibroblasts, the 70 vol% EtOH-precipitated sericin/PVA scaffolds showed the highest potential to promote cell proliferation. After applied to the full-thickness wounds of rats, the 70 vol% EtOH-precipitated sericin/PVA scaffolds showed significantly higher percentage of wound size reduction and higher extent of type III collagen formation and epithelialization, compared with the control scaffolds without sericin. The accelerated wound healing by the 70 vol% EtOH-precipitated sericin/PVA scaffolds was possibly due to (1) the bioactivity of sericin itself to promote wound healing, (2) the sustained release of precipitated sericin from the scaffolds, and (3) the activation and recruitment of wound healing-macrophages by sericin to the wounds. This finding suggested that the EtOH-precipitated sericin/PVA scaffolds were more effective for the wound healing, comparing with the EtOH-precipitated PVA scaffolds without sericin.

Preliminary clinical assessment of polyvinyl alcohol-tetrahydroxyborate hydrogels as potential topical formulations for local anesthesia of lacerations

OBJECTIVES

The aim of this study was to assess a novel semisolid material as a potential topical drug delivery system for acute laceration. The objectives were to correlate physical characterization data using rheologic studies and to compare with clinical assessment of performance in an emergency department (ED).

METHODS

Polyvinyl alcohol (PVA) hydrogels, cross-linked using tetrahydroxyborate (THB), were characterized using texture profile analysis. Formulation samples were applied to acute lacerations presented to the ED and factors, such as in vivo residency time and cohesive removal, were assessed.

RESULTS

Viscosity was shown to be related to mechanical characteristics, whereas adhesiveness depended on the THB concentration. Residence in, and clean removal from, lacerations was evaluated on 29 patients. Formulation F3 (10.0% PVA, 2.5% w/w THB) displayed the most appropriate characteristics for clinical use by scoring highest in qualitative assessments. Other formulations exhibited difficulties in application and removal due to excessive adhesiveness. The release of a model local anesthetic drug was proportional to the concentration of drug incorporated, but was not substantially affected by small changes in the formulation constituents.

CONCLUSIONS

Using a combination of pharmaceutical evaluation and clinical assessment, it was shown that cross-linked PVA semisolids are a suitable formulation for drug administration to acute lacerations, with potential for induction of anesthesia prior to wound repair.

Magnetically mediated release of ciprofloxacin from polyvinyl alcohol based superparamagnetic nanocomposites

Polymer nanocomposites exhibiting superparamagnetic behavior have been recognized as a promising tool to achieve targeted drug delivery using external magnetic field for treating complex diseases like cancers and tumors. The present investigation attempts to design a superparamagnetic nanocomposite which could desirably deliver ciprofloxacin drug by application of varying magnetic field. In order to achieve the proposed objectives, a polymer matrix of polyvinyl alcohol-g-polymethyl methacrylate was prepared by free radical polymerization and iron oxide particles were impregnated by in situ precipitation method. The prepared nanocomposites were characterized by techniques like FTIR, electron microscopy (SEM and TEM) and XRD and magnetization studies were performed to ensure superparamagnetic behavior. The antibiotic drug ciprofloxacin was loaded onto the magnetic nanocomposites and the influence of various factors such as percent loading, chemical composition of the nanocomposite, applied magnetic field, pH of the release medium were investigated on the release profiles of the drug. The chemical integrity of the drug and its antibacterial potential were also studied. The dynamics of the release process was also examined mechanistically.

Double-blinded, randomized, controlled trial of medicated versus nonmedicated merocel sponges for functional endoscopic sinus surgery

OBJECTIVE

This study aimed to compare differences between medicated and nonmedicated Merocel middle meatal spacers (MMSs) on sinonasal mucosal healing (histopathologic and endoscopic difference), patient discomfort, and pain on removal of the MMS following functional endoscopic sinus surgery.

METHODS

Forty-eight patients with chronic rhinosinusitis undergoing bilateral functional endoscopic sinus surgery were enrolled in a prospective study. Patients were randomized and blinded to receive a medication-soaked Merocel MMS (either one of budesonide, gentamicin, or manuka honey) in one nostril and a nonmedicated Merocel MMS in the contralateral side. Patients were seen on postoperative day 7 and were asked to complete a visual analogue score to report the level of discomfort from nasal packing on each side. Under endoscopic visualization, biopsies of mucosa were taken from both middle meati and assessed by a blinded pathologist to determine the level of mucosal inflammation on a scale of 0 to 4.

RESULTS

The budesonide-soaked Merocel MMS showed a trend toward reduced mucosal inflammation when compared to the control Merocel MMS, but the results were not statistically significant. There was no statistically significant difference in the degree of discomfort and pain on the removal of the packings between the medication-soaked Merocel MMS and the nonmedicated Merocel MMS, although there was a trend toward less pain for the manuka honey-soaked Merocel MMS.

CONCLUSIONS

Although our study failed to show any significant benefit from the addition of medication to the Merocel MMS, further studies with different compounds are recommended to determine whether a medicated MMS could indeed be a superior alternative to the standard MMS.

The effects of Vaseline gauze strip, Merocel, and Nasopore on the formation of synechiae and excessive granulation tissue in the middle meatus and the incidence of major postoperative bleeding after endoscopic sinus surgery

BACKGROUND

Endoscopic sinus surgery (ESS) has become the widely accepted procedure for the treatment of medically refractory chronic rhinosinusitis and nasal polyps. Nasal packing is usually placed after ESS to prevent synechia formation and postoperative bleeding and to support wound healing. The aim of this study was to evaluate the effects of three different nasal packing materials [Vaseline gauze strip, Merocel (Metronic Xomed, Jacksonville, FL, USA), and Nasopore (Polyganics, Rozenburglaan, Groningen, The Netherlands)] on the formation of synechiae and excessive granulation tissue in the middle meatus and incidence of major postoperative bleeding in patients who had undergone ESS.

METHODS

A total of 626 patients (1,018 sides) who had undergone ESS were studied retrospectively. Each patient chose one of the three different nasal packing materials according to his or her own preference. The outcome variable was the formation of synechiae and excessive granulation tissue in the middle meatus, which was identified from the medical records of endoscopic evaluations performed 3-4 weeks and 10-12 weeks after surgery. Major postoperative bleeding within 2 weeks after the operation was also documented for analysis. Finally, multiple logistic regression models were used to confirm the results of this study.

RESULTS

We did not observe significant intergroup differences in the effect on the formation of synechiae in the middle meatus. Nasopore packing showed a trend toward causing the formation of excessive granulation tissue during the early stages of wound healing (p=0.004). Patients who had received packing with Nasopore had a greater chance of undergoing readmission or additional packing because of major nasal bleeding within the first 2 weeks after the operation (p=0.03). Multivariable logistic regression models showed that Nasopore was a significant factor for the formation of excessive granulation tissue at 3-4 weeks after the operation (p=0.022) and for major postoperative nasal bleeding within the first 2 weeks after the operation (p=0.023).

CONCLUSION

Among patients who had undergone ESS for rhinosinusitis with or without polyps, the incidence of synechiae and excessive granulation tissue in the middle meatus and major postoperative bleeding in the patients who received Vaseline gauze packing was equivalent to the incidence of these complications in the patients who received Merocel. Nasopore was not superior to the other two nonabsorbable packing materials.

Arterial patency after repeated hepatic artery bland particle embolization

PURPOSE

To evaluate hepatic arterial patency after serial bland particle embolization procedures in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

All patients with HCC who underwent five or more hepatic artery bland embolization procedures with permanent particulate and spherical embolic agents between September 1996 and December 2007 were retrospectively reviewed. Data analyzed included patient demographics, vessels embolized, embolic agent used, and duration of arterial patency.

RESULTS

Forty-three patients were identified who underwent five or more bland embolization procedures in the same arterial distribution. Of the 43 patients examined, 83% (n = 36) showed no change in the hepatic arterial tree after repeated bland embolization (mean treatment period of 48 months +/- 23). Six patients (13%) exhibited occlusion of a fifth-order or more distal vessel after an average of 5 embolizations +/- 2 over a period of 34 months +/- 27. A single case of vascular occlusion of a fourth-order vessel was observed after five embolizations over a period of 52 months.

CONCLUSIONS

Repeated bland embolization of the hepatic arteries in HCC preserves patency of the hepatic arterial vasculature despite the fact that embolization is carried out to complete stasis.

[Study on preparation and determination of Liaojin plastics]

OBJECTIVE

To establish the optimum preparation and determination method of Liaojin plastics through screening different factors.

METHODS

The Orthogonal Test was applied to optimize the best preparation technology, and the content of peoniflorin in Liaojin plastics was determined by HPLC.

RESULTS

The best matrix proportion of plastics was PVA-124 : alcohol : acetone : distilled water = 1 : 4 : 2 : 10; The average recovery of plastics was 98.56%, RSD was 1.66% (n = 9), and the average content of six samples was 0.6817 mg/g, RSD was 1.44%.

CONCLUSION

The good quality plastics can be produced through this process. HPLC determination method is simple, reliable and can be used in the quality control of Liaojin plastics.

Micelles Based on Polyvinyl Alcohol Substituted with Oleic Acid for Targeting of Lipophilic Drugs

Polymeric micelles based on polyvinyl alcohol substituted with oleic acid were used as vehicles for progesterone and folic acid. The ability of this amphiphilic polymer to entrap lipophilic drugs and to generate stable micelles in aqueous neutral medium makes it a good candidate for drug delivery. The release of the loaded drugs in acidic environments represents another important property of these systems. Size of micelles, their stability, and their drug-loading capacity were evaluated, as well as the in vitro controlled-release profiles at pH 7.4 and 5.5.

Nasal packing in cosmetic and functional nasal surgery

OBJECTIVE

To evaluate the routine use of nasal packing after cosmetic and functional nasal surgery.

METHODS

Prospective collection from 2005 to 2006 at King Abdulaziz University Hospital in Riyadh for 54 patients post-septorhinoplasty with and without submucous diathermy or lateralization of inferior turbinate were evaluated for efficacy and complications of nasal packing which kept for different duration.

RESULTS

All 54 patients had septoplasty, 21 with rhinoplasty, 12 with SMD, and 24 patients had inferior turbinate lateralization. Eight cm slim Merocel packed in 67 nasal cavity sides, 8 cm regular Merocel packed in 24 sides and 10 cm regular Merocel packed in 6 sides. Thirty-seven patients had the pack for 6 hours then removed and 17 patients had it for 24 hours. Forty-one patients with no significant discomfort, 13 patients with mild to moderate discomfort.

CONCLUSION

Septorhinoplasty and SMD or lateralization of inferior turbinate can be managed without packing or any other hemostatic measures.

Lower gastrointestinal bleeding treated with transcatheter arterial embolization. Case report and review of the literature

Acute lower gastrointestinal bleeding, is often a dramatic situation, associated with mortality rate up to 28%. Currently transcatheter alternatives have found their place in the therapeutic spectrum of this situation. An interesting question is when should this procedure be performed and which are the difficulties when performing it. We present the case of a 75-year old woman with acute massive lower gastrointestinal bleeding on the tenth post-operative day of a colic and partial ileal resection. Superselective angiography of the superior mesenteric artery was obtained that disclosed marked contrast extravasation of distal branches of the left colic artery as well as from a small branch feeding the distal enteric anastomoses. Clinical success was achieved after superselective embolization which was accomplished by using polyvinyl alcohol particles. The patient was discharged 5 days later and there were no procedure-related complications during 6-month follow-up period. So, especially in post-operative patients who are considered to be poor candidates for surgical treatment, arterial embolotherapy should be established not only as treatment option, but also as first line therapy for LGI bleeding.

The effects of merocel and glove finger tampon applications on the nasal septum mucosa of rabbits

OBJECTIVE

The use of tampons after nasal septum surgery is important for both prevention of postoperative bleeding and stabilization of the nasal flaps and the septum. One of the most important factors in achieving rapid postoperative recovery is the choice of the nasal tampon material, among many, to produce minimal damage on the nasal mucosa. In this study, the histopathological effects of the glove finger and merocel tampons, which are commonly used in clinical applications, have been investigated on the nasal mucosa of rabbits.

MATERIALS AND METHODS

In this study, merocel and glove finger tampons were used for nasal packing in one-sided nasal cavities of 16 adult New Zealand rabbits. The animals were randomized into two groups, each consisting of eight animals. The tampons were removed after 48 hours.

RESULTS

Histological examination showed that if the merocel was in a glove finger, it did not create any damage to mucosal integrity and lamina propria. However, in the group where merocel was used directly, the epithelium of the nasal mucosa was shortened and demonstrated loss of cilia and in four of the eight specimens, it was partly from lamina propria.

CONCLUSION

It is concluded that the use of merocel in glove finger tampon leads to a lesser degree of damage in the lamina propria, and may facilitate rapid mucosal wound healing postoperatively.

Evaluation of different calibrated spherical polyvinyl alcohol microspheres in transcatheter arterial chemoembolization: VX2 tumor model in rabbit liver

PURPOSE

To assess whether porosity and compressibility of calibrated spherical polyvinyl alcohol (PVA) microspheres affect doxorubicin plasma and tumor concentrations after transcatheter arterial chemoembolization (TACE) in a VX2 rabbit model.

MATERIALS AND METHODS

Fifteen rabbits were divided into three groups of five rabbits each. Three different types of calibrated spherical PVA microspheres with variable levels of porosity and compressibility were blindly evaluated. TACE was performed by injecting a mixture of doxorubicin (5 mg) and iodized oil (0.5 mL) followed by injection of the embolic material (0.3-0.5 mL). Plasma concentrations of doxorubicin and doxorubicinol were analyzed 20, 40, 60, and 120 minutes and 2 days after TACE, and liver tissue and tumor doxorubicin concentrations were measured 2 days after TACE.

RESULTS

All calibrated spherical PVA microspheres showed similar patterns of plasma doxorubicin and doxorubicinol release and tumor concentration of doxorubicin. There were no significant differences of drug levels in either plasma or tumor in each group (P > .05).

CONCLUSIONS

After TACE in a rabbit model of liver cancer, testing of three different types of spherical PVA microspheres with varying degrees of porosity and compressibility showed no significant differences in the plasma doxorubicin release pattern and tumor doxorubicin uptake.

Selective palliative transcatheter embolization of bony metastases from renal cell carcinoma

To examine whether transcatheter embolization of bone metastases is an effective palliative option for patients with renal cell carcinoma (RCCa). A retrospective review of 21 patients presenting for palliative embolization of painful RCCa skeletal metastases was performed. Details regarding anatomic sites, procedural details, and embolization materials were collected. The clinical response of the patient was assessed from clinic visits and analgesic use. Thirty separate embolization procedures were used to treat 39 metastatic lesions (18 pelvic, 8 lower extremity, 3 upper extremity, 5 rib/chest well, and 5 vertebral lesions). Five patients underwent more than one embolization. Polyvinyl alcohol was used in all 30 embolization procedures. Additional embolic materials were used in 16 of 30 procedures. A clinical response was achieved at 36 treated sites; the mean duration fo the response was 5.5 months. Selective embolization of bony renal cell carcinoma metastases can provide effective palliation in a patient population which has limited therapeutic options.

An evaluation of Merocel and Series 5000 nasal packs in patients following nasal surgery: a prospective randomised trial

OBJECTIVE

The primary objective of this study was to compare postoperative pain levels between Merocel and Series 5000 nasal packs.

DESIGN

A prospective randomised, single blind, paired control trial.

SETTING

A single consultant in two tertiary Otolaryngology units.

PARTICIPANTS

Twenty-four adults, ASA 1, who underwent septoplasty, endoscopic sinus surgery or both, were considered after exclusion criteria were applied: bleeding abnormalities, patients taking anticoagulant medications and any significant co-morbidity requiring admission beyond 24-h postoperatively. Twenty-one patients were randomly assigned to have one side of their nose packed with Merocel pack and the other with Series 5000 overnight.

MAIN OUTCOME MEASURES

The difference in pain levels, using a visual analogue scale, both with the pack in situ and on removal.

RESULTS

In 20 patients, the mean pain scores while the packs were in situ were 3.78 for Merocel and 3.62 for Series 5000 and was not found to be significantly different (P = 0.65. 95% CI = -0.57-0.89). The mean pain score on removal of the Merocel pack was five and for the Series 5000 was 3.08. The Series 5000 pack was significantly less painful than Merocel on removal (P < 0.0001. 95% CI = 1.11-2.7). Both were equally effective in their stability and haemostatic effect.

CONCLUSIONS

Both the Merocel and Series 5000 packs are effective packs regarding haemostasis and have equivalent pain levels while in situ. However, the Series 5000 pack was significantly less painful on removal of the pack.

Emergency embolization of a bleeding renal angiomyolipoma using polyvinyl alcohol particles

Angiomyolipomas (AMLs) are hamartomatous lesions consisting of abnormal blood vessels, smooth muscle, and adipose tissue. Bilateral AMLs invariably point to a diagnosis of tuberous sclerosis complex (TSC). The risk of hemorrhage in AML is related to tumor size, growth of the tumor, hypervascularization, presence of aneurysms, and association with TSC. We report a case of a young male who presented with painless hematuria. He was diagnosed with bilateral renal AMLs on ultrasonography and computed tomography. The large bleeding lesions were identified by renal angiography and selectively embolized using polyvinyl alcohol particles. To the best of our knowledge, isolated use of polyvinyl alcohol particles has not been previously reported.

Polyvinyl alcohol embolization adjuvant to oily chemoembolization in advanced hepatocellular carcinoma with arterioportal shunts

OBJECTIVE

To assess the feasibility and safety of polyvinyl alcohol (PVA) embolization adjuvant to transarterial oily chemoembolization (P-TACE) in advanced hepatocellular carcinoma (HCC) with arterioportal shunts (APS).

MATERIALS AND METHODS

Nineteen patients who underwent PVA embolization for APS before a routine chemoembolization (TACE) procedure were retrospectively reviewed. 10 of these 19 patients underwent follow-up TACE or P-TACE after P-TACE (Group A), but nine patients underwent only initial P-TACE because of progression of HCC and/or underlying liver cirrhosis (Group B). Hepatic function tests, APS grades, and portal flow directions were evaluated before and after P-TACE sessions. Complications after procedures and survival days were also evaluated.

RESULTS

In group A, APS grade was improved in eight patients and five of six patients with hepatofugal flow showed restored hepatopetal flow postoperatively. No immediate complication was developed in either group. Transient hepatic insufficiency developed in eight (42.1%) of 19 patients after P-TACE, and seven (87.5%) of these eight recovered within two weeks under conservative care. The mean and median survival time all study subjects was 280 days and 162 days.

CONCLUSION

P-TACE is feasible and safe in advanced HCC patients with APS.

Endoscopic intranasal reduction of the orbit in isolated blowout fractures

CONCLUSION

Endoscopic intranasal reduction of the orbital floor with a detachable temporary balloon, or of the medial orbital wall with a silastic sheet and Merocel packing, provided good functional results and definite advantages. We suggest that these techniques are another surgical alternative for isolated orbital floor or medial wall blowout fractures that do not accompany any associated fractures of the orbital rim.

OBJECTIVES

Extended applications of endoscopic sinus surgery have reported endoscopic intranasal reduction or reconstruction of the orbital wall with good functional and cosmetic results. We present our experience with endoscopic intranasal reduction of the orbit in isolated orbital floor and/or medial wall blowout fractures, treated by reduction of the orbital floor with a detachable temporary balloon, or of the medial orbital wall with a silastic sheet and Merocel packing.

SUBJECTS AND METHODS

Floor reduction: After creating a wide middle meatal antrostomy, herniated orbital contents and fracture-displaced floor are mobilized and reduced. The orbital floor is supported by a saline filled balloon, which is connected with an infant feeding catheter and passed through the middle meatal antrostoma. After confirming the reduction of the orbital floor by postoperative CT, the catheter is ligated and cut in short to keep it in the nasal cavity. Medial wall reduction: After completing an intranasal ethmoidectomy, herniated orbital contents and fractured lamina papyracea are mobilized and reduced. The shape of the medial orbital wall is fixed by a silastic sheet and Merocel packing saturated with an antibiotic solution. Surgery was performed when the eye function could be accurately assessed, usually at 7 to 10 days following the injury. Temporary supporting of the orbital wall with a detachable temporary balloon, or a silastic sheet and Merocel packing was removed 4 weeks after surgery in the out-patient clinic.

RESULTS

We have experienced 40 cases of endoscopic intranasal reduction of the orbit in blowout fractures. CT scan confirmed isolated orbital floor fracture in 11 patients, isolated medial wall fracture in 17 patients, and combined fractures of the orbital floor and the medial wall in 12 patients. Twenty five patients had diplopia, 20 patients had limitation of eye movement, and 14 patients developed enophthalmos. Thirty three of the 40 patients recovered completely without any residual eye symptoms or complications.

Polyvinyl alcohol gel prevents abdominal adhesion formation in a rabbit model

OBJECTIVE

To evaluate the function and biocompatibility of the new adhesion barrier PVA gel (polyvinyl alcohol + carboxymethylated cellulose) in the prevention of postsurgical peritoneal adhesions in a rabbit sidewall model. To evaluate and compare the routinely used 4% icodextrin.

DESIGN

A prospective randomized controlled study was designed to evaluate the effectiveness of PVA gel in reducing postoperative adhesion formation.

SETTING

Clinical laboratory in Germany.

ANIMAL(S)

Eighty female albino rabbits (HM Small Russian; 2.4-3.6 kg).

INTERVENTION(S)

All animals underwent trauma of the abdominal sidewall at the clinical laboratory. The PVA gel was placed at the sidewall defect in 50 cases. In two further groups, 18 animals had no treatment (control group), and 12 animals were treated with 4% icodextrin.

MAIN OUTCOME MEASURE(S)

Biocompatibility, mechanical properties of PVA gel, adhesion development, and device handling were observed.

RESULT(S)

The PVA gel showed good biocompatibility, no side effects, and excellent adhesion prevention. Although 100% of the untreated control group as well as the animals treated with 4% icodextrin developed adhesion formation, only around 25% of those rabbits that were treated with PVA gel showed adhesions.

CONCLUSION(S)

These data show that PVA gel functions as an excellent adhesion barrier.

Development of a hypertrophic ovarian artery after uterine artery embolization with polyvinyl alcohol particles

Uterine artery embolization (UAE) for the treatment of symptomatic leiomyomata has shown excellent short-term clinical efficacy and minimal complications, yet recurrences after successful treatments at mid- and long-term follow-up have been reported. Exact etiologies for such recurrences have not been fully understood. We present a case of symptom recurrence with the development of a hypertrophic ovarian artery after successful UAE with polyvinyl alcohol particles, successfully treated with ovarian and repeat UAEs.

Single-layer transdermal film containing lidocaine: Modulation of drug release

We have recently described an innovative drug delivery system, a water-based and vapor permeable film intended for dermal and/or transdermal delivery. The aim of this work was to modulate the delivery of the model drug lidocaine hydrochloride from the transdermal film across rabbit ear skin. The effect of drug loading, of film-forming polymer type and content, of adhesive and plasticizer on lidocaine transport across the skin was evaluated. Additional objective was to evaluate the effect of occlusion on the kinetics of lidocaine transport, by applying an occlusive backing on the surface of the transdermal film. From the data obtained it can be concluded that the transdermal film acts as a matrix controlling drug delivery. The film-forming polymer molecular weight had a negligible effect on drug penetration, while its content was more effective. The choice of the adhesive seems to be the most important variable governing drug transport. In particular, the presence of lauric acid combined with a basic drug, such as lidocaine, can produce a relevant improvement in permeation, because of the formation of an ion pair. Concerning the kinetics, drug depletion is responsible for the declining permeation rates observed in the late times of permeation.

Cellulose acetate butyrate–pH/thermosensitive polymer microcapsules containing aminated poly(vinyl alcohol) microspheres for oral administration of DNA

The aim of this work is to safely transport bioadhesive microspheres loaded with DNA to intestine and to test their bioadhesive properties. Poly(vinyl alcohol) (PVA) microspheres were prepared by dispersion reticulation with glutaraldehyde and further aminated. These microspheres were firstly loaded with plasmid DNA by electrostatic interactions and then entrapped in cellulose acetate butyrate (CAB) microcapsules for gastric protection. The entrapped PVA microspheres do not have enough force by swelling to produce the rupture of CAB shell, therefore the resistance of microcapsules was weakened by incorporating different amount of the pH/thermosensitive polymer (SP) based on poly(N-isopropylacrylamide-co-methyl methacrylate-co-methacrylic acid) (NIPAAm-co-MM-co-MA). This polymer is insoluble in gastric juice at pH 1.2 and 37 degrees C, but quickly solubilized in intestinal fluids (pH 6.8 and pH 7.4). Therefore, DNA loaded PVA microspheres were not expelled in acidic media but were almost entirely discharged in small intestine or colon. The integrity of DNA after entrapment was tested by agarose gel electrophoresis indicating that no DNA degradation occurs during encapsulation. The percentage of adhered microspheres on the mucus surface of everted intestinal tissue was 65+/-18% for aminated PVA microspheres without DNA and almost 50+/-15% for those loaded with DNA. Non-aminated PVA microspheres display the lowest adhesive properties (33+/-12%). In conclusion DNA loaded microspheres were progressively discharged in intestine. The integrity of DNA was not modified after entrapment and release, as proved by agarose gel electrophoresis. Both loaded and un-loaded aminated microspheres display good bioadhesive properties.

The effect of redox polymerisation on degradation and cell responses to poly (vinyl alcohol) hydrogels

Biocompatible, degradable hydrogel systems that can cure in situ following injection as a liquid are useful as a base for tissue engineering and drug delivery. In this study, poly (vinyl alcohol) (PVA) polymers were modified with degradable crosslinkers and formulated for either ultraviolet (UV) light initiation or chemical initiation using an oxidation/reduction (redox) curing method. A major objective was to compare the properties of degradable PVA hydrogels formed via two routes of curing. The effect of macromer concentration, degree of hydrolysis and functional group density on the degradation profiles was investigated. Also, since the hydrogels have been designed to be injected as a liquid for in situ curing, the effect of modified macromer solutions and degradation products on cell growth was investigated. Total degradation times ranged from approximately 20 days up to 120 days and increased in direct proportion with percent macromer. Initiation method (UV or redox) did not significantly impact on time for total degradation. While aqueous solutions of the modified macromer induced some cell growth inhibition, mainly associated with oxidative solutions, degradation products showed relatively low cell growth inhibition. Degradable PVA hydrogels tailored to produce networks with various degradation profiles can be cured by redox initiation and have potential as injectable polymers for soft-tissue engineering and drug delivery.

The use of tetracaine 0.25% solution in nasal packing removal

BACKGROUND

The aim of this study was to evaluate efficacy of Merocel nasal package rehydration with tetracaine 0.25% solution, in reducing discomfort of nasal packing removal after septoplasty.

METHODS

A prospective study was conducted on patients undergoing pure septoplasty. Merocel packing was applied in each side and kept for 2 days postoperatively. Merocel was rehydrated before removal, with 4 mL of saline on one side and 4 mL of tetracaine 0.25% solution on the other side. Patients were asked to evaluate severity of pain during nasal packing removal on each side by a visual analog scale. Patients' data, pain score, and potential complications were placed in a database and statistically assessed.

RESULTS

Our series consisted of 141 persons. Statistical analysis showed significant lower pain score in favor of the tetracaine group. No tetracaine complications or side effects occurred.

CONCLUSION

Merocel packing rehydration with tetracaine 0.25% solution is an easy, safe, inexpensive, and effective analgesia method for nasal packing removal in septoplasty.

Tracking the urinary excretion of high molar mass poly(vinyl alcohol)

The fate of poly(vinyl alcohol) (PVA) of weight average molar mass of 125,000 g/mol after administration into the peritoneum of rabbits has bean studied by various methods. PVA was spin-labeled with a nitroxide radical and then detected in urine using electron spin resonance (ESR) spectroscopy. Furthermore, unlabeled polymer was also administered to rabbits, then the urine was collected, dialyzed, precipitated, and the excretion of PVA was confirmed by size exclusion chromatography (SEC), FTIR spectroscopy, and (1)H NMR spectroscopy. ESR and SEC results show that, despite its relatively high molar mass, PVA is excreted through the kidneys without significant molar mass changes. Nevertheless, NMR and FTIR spectra show slight differences between the excreted and neat PVA. Possible causes of these discrepancies are discussed.