[Aneurysmal subarachnoid hemorrhage: group of study of cerebrovascular pathology of the Spanish society of neurosurgery management guideline]. / Hemorragia subaracnoidea aneurismática: guía de tratamiento del grupo de patología vascular de la sociedad Española de neurocirugía.

An actualized revision of the most important aspects of aneurismal subarachnoid hemorrhage is presented from the guidelines previously published by the group of study of cerebrovascular pathology of the Spanish Society of Neurosurgery. The proposed recommendations should be considered as a general guide for the management of this pathological condition. However, they can be modified, even in a significant manner according to the circumstances relating each clinical case and the variations in the therapeutic and diagnostic procedures available in the center attending each patient.

Idiopathic subarachnoid hemorrhage: a multicentre series of 220 patients.

BACKGROUND. The Spanish neurosurgical society created a multicentre data base on spontaneous SAH to analyze the real problematic of this disease in our country. This paper focuses on the group of patients with idiopathic SAH (ISAH). METHODS. 16 participant hospitals collect their spontaneous SAH cases in a common data base shared in the internet through a secured web page, considering clinical, radiological, evolution and outcome variables. The 220 ISAH cases collected from November 2004 to November 2007 were statistically analyzed as a whole and divided into 3 subgroups depending on the CT blood pattern (aneurysmal, perimesencephalic, or normal). RESULTS. The 220 ISAH patients constitute 19% of all 1149 spontaneous SAH collected in the study period. In 46,8% of ISAH the blood CT pattern was aneurysmal, which was related to older age, worse clinical condition, higher Fisher grade, more hydrocephalus and worse outcome, compared to perimesencephalic (42.7%) or normal CT (10.4%) pattern. Once surpassed the acute phase, outcome of ISAH patients is similarly good in all 3 ISAH subgroups, significantly better as a whole compared to aneurysmal SAH patients. The only variable related to outcome in ISAH after a logistic regression analysis was the admission clinical grade. CONCLUSIONS. ISAH percentage of spontaneous SAH is diminishing in Spain. Classification of ISAH cases depending on the blood CT pattern is important to differentiate higher risk groups although complications are not negligible in any of the ISAH subgroups. Neurological status on admission is the single most valuable prognostic factor for outcome in ISAH patients.

A randomized trial of endovascular versus surgical management of ruptured intracranial aneurysms: Interim results from ISAT2.

BACKGROUND AND PURPOSE: Appropriate management of ruptured intracranial aneurysm (RIA) in patients eligible for surgical clipping but under-represented in or excluded from previous randomized trials remains undetermined. METHODS: The International Subarachnoid Aneurysm Trial-2 (ISAT-2) is a randomized care trial comparing surgical versus endovascular treatment (EVT) of RIA. All patients considered for surgical clipping but eligible for endovascular treatment can be included. The primary endpoint is death or dependency on modified Rankin score (mRS>2) at 1 year. Secondary endpoints are 1 year angiographic results and length of hospital stay. RESULTS: An interim analysis was performed after 103 patients were treated from November 2012 to July 2017 in 4 active centers. Fifty-two of the 55 patients allocated to surgery were treated by clipping, and 45 of the 48 allocated to EVT were treated by coiling, with 3 crossovers in each arm. The main endpoint (1 year mRS>2), available for 76 patients, was reached in 16/42 patients allocated to clipping (38%; 95%CI: 25%-53%), and 10/34 patients allocated to coiling (29%; 17%-46%). One year imaging results were available in 54 patients: complete aneurysm occlusion was found in 23/27 patients allocated to clipping (85%; 67%-94%), and 18/27 patients allocated to coiling (67%; 47%-81%). Hospital stay exceeding 20 days was more frequent in surgery (26/55 [47%; 34%-60%]) than EVT (9/48 [19%; 10%-31%]). CONCLUSION: Ruptured aneurysm patients for whom surgical clipping may still be best can be managed in a randomized care trial, which is feasible in some centers. More participating centers are needed.

Sublethal zinc exposure has a detrimental effect on reproductive performance but not on the cyst hatching success of Artemia parthenogenetica.

The sublethal zinc toxicity to Artemia parthenogenetica as regards the possibility of colonization of zinc polluted salterns by means of cysts has been assessed by a cyst hatching assay and a life table approach. Emergence and hatching at different times as well as the whole hatching profile were taken as end-points for evaluating success of development. Demographic and reproductive parameters calculated according to the Lotka equation were used as an indicator of the chronic toxicity of the population. No adverse effects of waterborne zinc were found on hatching and emergence of cysts of A. parthenogenetica at any of the concentrations tested (0.01 mg/l, 0.1 mg/l, 0.5 mg/l, 1 mg/l, 5 mg/l). Chronic zinc exposure at 0.08 mg/l had detrimental effects on A. parthenogenetica fecundity, as detected by a decrease in the percentage of fertile females, which in turn produces a decrease in r. Chronic toxicity of zinc may be a limiting step for A. parthenogenetica colonization and the establishing of permanent populations in zinc-polluted brine ponds.

[Spontaneous Subarachnoid Haemorrhage multicenter database from the Group for the Study of Vascular Pathology of the Spanish Society for Neurosurgery: presentation, inclusion criteria and development of an internet-based registry]. / Base de datos multicéntrica de hemorragia subaracnoidea espontánea del Grupo de Trabajo de Patología Vascular de la Sociedad Española de Neurocirugía: presentación, criterios de inclusión y desarrollo de una base de datos en internet.

INTRODUCTION: Subarachnoid haemorrhage is one of the most severe neurosurgical diseases. Its study is crucial for improving the care of these patients in our environment. With this goal the Group for the Study of Neurovascular Pathology of the Spanish Society for Neurosurgery (SENEC) decided to create a multicenter registry for the study of this disease. MATERIALS AND METHODS: In this database we have prospectively included all cases with spontaneous subarachnoid haemorrhage admitted to the participant hospitals from November 2004 to November 2007. The fields to be included in the database were selected by consensus, including age, past medical history, clinical characteristics at admission, radiological characteristics including presence or absence of an aneurysm and its size and location, type and complications of the aneurysm treatment, outcome assessed by the Glasgow Outcome Scale (GOS) at discharge and six months after the bleeding as well as the angiographic result of the aneurysm treatment. All fields were collected by means of an electronic form posted in secure web page. RESULTS: During the three years of study a total of 1149 patients have been included by 14 Hospitals. The time needed to fill in a patient in the registry is approximately 3.4 minutes. This series of patients with spontaneous SAH is similar to other non-selected in-hospital series of SAH. The mean age of the patients is 55 years and there is a 4:3 female to male ratio. In relation to the severity of the bleeding 32% of the patients were in poor clinical grade at admission (WFNS 4 or 5). 5% of the patients died before angiography could be performed. An aneurysm was confirmed as the origin of the bleeding in 76% of the patients (aSAH), while in 19% of the patients no lesion was found in the angiographic studies and were thus classified as idiopathic subarachnoid hemorrhage (ISAH). Of those patients with aSAH, 47% were treated endovascularly, 39% surgically, 3% received a combined treatment and 11% did not receive any treatment for their aneurysm because of early death. Regarding outcome, there is a 22% mortality in the series. Only 40% of the patients with aSAH reached a good outcome at discharge (GOS = 5). CONCLUSIONS: Spontaneous SAH continues to be a disease with high morbidity and mortality. This database can be an ideal instrument for improving the knowledge about this disease in our environment and to achieve better results. It would be desirable that this database could in the future be the origin of a national registry of spontaneous SAH.

[Brachial plexus block for minimally invasive parathyroidectomy: report of 3 cases]. / Bloqueo del plexo cervical en paratiroidectomía mínimamente invasiva. A propósito de tres casos.

The brachial plexus block, either deep or superficial, is one of the anesthetic techniques used in parathyroidectomy. The block is easy to perform and has few hemodynamic side effects. Surgery can be carried out in an awake patient. We describe 3 cases of patients with primary hyperparathyroidism (parathyroid adenoma) who underwent unilateral minimally invasive parathyroidectomy under regional anesthesia and sedation with 2 mg of midazolam plus remifentanil at dosages ranging from 0.6 to 0.1 microg kg(-1) min(-1). To provide a deep cervical block, we administered 15 mL of 0.75% ropivacaine. For a superficial block, 15 mL of 0.2% ropivacaine was used. The procedure could be completed in all 3 patients under regional anesthesia. The latency time for the block ranged from 21 to 30 minutes, and remifentanil dosages from 0.05 to 0.09 microg kg(-1) min(-1) were administered for procedures that lasted 30 to 45 minutes. No patient required postoperative opioids or antiemetics, although a local anesthetic had to be used at the moment of incision for 1 patient. All 3 patients were discharged the same day. We wish to underline the utility of the brachial plexus block for parathyroid surgery. The technique is easy to perform, safe, and effective; as a result, surgery can be carried out on an outpatient basis.

Group versus traditional prenatal care in low-risk women delivering at term: a retrospective cohort study.

OBJECTIVE: Group prenatal care (GC) models are receiving increasing attention as a means of preventing preterm birth; yet, there are limited data on whether group care improves perinatal outcomes in women who deliver at term. The purpose of this study was to evaluate our institutional experience with GC over the past decade and test the hypothesis that GC, compared with traditional individual care (TC), improves perinatal outcomes in women who deliver at term. STUDY DESIGN: We performed a retrospective cohort study of women delivering at term who participated in GC compared with TC. A group of 207 GC patients who delivered at term from 2004 to 2014 were matched in a 1:2 ratio to 414 patients with term singleton pregnancies who delivered at our institution during the same period by delivery year, maternal age, race and insurance status. The primary outcome was low birth weight (<2500 g). Secondary outcomes included early term birth (37.0 to 38 6/7 weeks), 5 min APGAR score <7, special care nursery admission, neonatal intensive care unit (NICU) admission, neonatal demise, cesarean section and number of prenatal visits. Outcomes were compared between the two groups using univariable statistics. RESULTS: Baseline characteristics were similar between the two matched groups. GC was associated with a significant reduction in low birth weight infants compared with TC (11.1% vs 19.6%; relative risk (RR) 0.57; 95% confidence interval (CI) 0.37 to 0.87). Patients in GC were significantly less likely than controls to require cesarean delivery, have low 5 min APGAR scores and need higher-level neonatal care (NICU: 1.5% vs 6.5%; RR 0.22; 95% CI 0.07 to 0.72). There were no significant differences in rates of early term birth and neonatal demise. CONCLUSIONS: Low-risk women participating in GC and delivering at term had a lower risk of low birth weight and other adverse perinatal outcomes compared with women in TC. This suggests GC is a promising alternative to individual prenatal care to improve perinatal outcomes in addition to preterm birth.

Extradural hematoma: analysis of factors influencing the courses of 161 patients.

The clinical and computed tomographic (CT) findings in a series of 161 consecutive patients operated upon for postraumatic extradural hematoma are analyzed. Thirteen (8%) patients had delayed epidural hematoma formation. The overall mortality for the series was 12%, significantly lower than that observed during the prior "angiographic" period at the same unit (30%). Because all but 1 of the deaths occurred among the 66 patients unconscious at the time of operation (27% mortality in this subgroup), the authors sought differential factors between comatose and noncomatose patients at operation. There were no significant differences between these groups in age, sex, mechanism of injury, preoperative course of consciousness (lucid interval or not), or epidural hematoma location and shape. In contrast, significant differences were seen between the two subgroups in trauma-to-operation interval, hematoma volume, CT hematoma density (mixed low-high CT density vs. homogeneous hyperdensity), midline displacement, severity of associated intracranial lesions, and postoperative intracranial pressure (ICP). Patients comatose at operation usually evidenced a more rapid clinical deterioration (a shorter trauma-to-operation interval) and tended to have a large hematoma volume, a higher incidence of mixed CT density clot (hyperacute bleeding), more marked shift of midline structures, more severe associated lesions, and higher postoperative ICP levels.

Comparison of the clinical presentation of symptomatic arteriovenous malformations (angiographically visualized) and occult vascular malformations.

The authors compared the clinical presentations of angiographically apparent arteriovenous malformations (AVMs) and angiographically occult vascular malformations (AOVMs) of the brain in 188 consecutive patients treated when computed tomography and magnetic resonance were available. There were 133 patients (70.7%) with AVMs and 55 patients (29.2%) with AOVMs. AOVMs tended to occur more frequently in male patients and in the posterior fossa and to present earlier clinically than AVMs, but differences were not significant. One distinctive feature was the greater size of AVMs, as compared with AOVMs. Presentation by hemorrhage occurred in 64.3% of the patients with AVMs and in 61.8% of those with AOVMs. Malformations of both types located in the posterior fossa presented with hemorrhage more frequently (84.2% of AVMs and 78.5% of AOVMs) than similar lesions lying above the tentorium (60.8% of AVMs and 56% of AOVMs). Bleeding was more severe in patients with AVMs than in those with AOVMs, as indicated by the higher mortality associated with hemorrhage (7.5 vs. 3.6% of the cases) and the more frequent and marked decrease in the level of consciousness observed at admission (34 vs. 16.2% of drowsy or comatose patients). Brain hematomas caused by AVMs were on average bigger than those caused by AOVMs (58.8 and 20% of large hematomas, respectively), and intraventricular and subarachnoid hemorrhages were also more common and profuse in patients with AVMs. However, AOVMs bled subsequently more times than AVMs (61.7 vs. 15.6%), before they were diagnosed and treated, leading to a higher nonoperative morbidity (16.3 vs. 13.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in systemic blood pressure and cardiac rhythm induced by therapeutic compression of the trigeminal ganglion.

Percutaneous compression of the trigeminal ganglion, which is currently being used for the control of trigeminal neuralgia, induces marked intraoperative elevations of the systemic blood pressure and heart rate changes, which may increase the risk of cardiovascular complications. We have analyzed the characteristics of the arterial hypertensive response and the cardiac rhythm changes induced by percutaneous compression of the trigeminal ganglion in 42 consecutive, unselected patients undergoing operations for essential trigeminal neuralgia under three different regimens of anesthesia. The first 22 patients (Group 1) underwent operations under brief general anesthesia without endotracheal intubation. The following 10 patients (Group 2) had general anesthesia with intubation and mechanical ventilation and received larger doses of hypnotic and analgesic agents. Finally, 10 more patients (Group 3), who had general anesthesia with intubation, underwent local anesthetic blockade of Meckel's cave (injection of 1 ml of 1% lidocaine) before ganglion compression. Foramen ovale puncture elicited bradycardia in the majority of the patients of Groups 2 and 3, but only four patients (18%) of Group 1 showed bradycardia. Ganglion compression caused marked tachycardia in all patients of Groups 1 and 2; about one-third of the patients also had extrasystoles. By contrast, patients of Group 3, who had local anesthetic blockade of Meckel's cave before ganglion compression, did not develop tachycardia or extrasystoles. Foramen ovale puncture elicited marked elevations of the systemic blood pressure in all patients. Ganglion compression further increased blood pressure, except in patients of Group 3, who had local anesthetic blockade of Meckel's cave.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous microcompression of the gasserian ganglion for trigeminal neuralgia.

The authors report 144 cases of trigeminal neuralgia treated by percutaneous microcompression of the trigeminal ganglion (PMTG). The operation was performed under short-lasting barbiturate anesthesia without endotracheal intubation. Meckel's cave was cannulated with a No. 4 Fogarty catheter and the balloon was inflated for 1 minute. The average intraluminal pressure required for adequate compression of the ganglion was about 1200 mm Hg. All patients were initially relieved of their neuralgia. In a follow-up period ranging from 6 months to 4 1/2 years, 14 patients (9.7%) developed recurrence of pain between 10 and 35 months after surgery. Eleven patients underwent a second PMTG. All nine early failures and 10 of the 11 late recurrences occurred in cases with technical deficiencies. Most of the minor surgical complications observed were also related to avoidable technical errors. There were no anesthetic complications and no deaths. All patients developed mild to moderate postoperative hemifacial numbness with or without objective hypesthesia. Both subjective and objective deficits gradually diminished with time and were well tolerated. One year after the operation nearly 40% of the patients still had patches of slightly decreased sensation in one or more trigeminal divisions and 16% had mild dysesthesia. Anesthesia dolorosa or keratitis was not reported. The PMTG procedure is easy to perform and requires a short operative time and a brief period of hospitalization. It is well tolerated by patients, who describe it as a totally pain-free experience. Morbidity is minimal and recurrence of neuralgia does not seem to be higher than with alternative procedures.

Head-injured patients who talk and deteriorate into coma. Analysis of 211 cases studied with computerized tomography.

Of 838 patients with severe head injuries admitted since the introduction of computerized tomography, 211 (25.1%) talked at some time between trauma and subsequent deterioration into coma. Of these 211 patients, 89 (42.2%) had brain contusion/hematoma, 46 (21.8%) an epidural hematoma, 35 (16.6%) a subdural hematoma, and 41 (19.4%) did not show focal mass lesions. Thus, four of every five patients who deteriorated into coma after suffering an apparently nonsevere head injury had a mass lesion potentially requiring surgery: the mass was intracerebral in 52.3% of the cases and extracerebral in 47.6%. Patients aged 20 years or less had a 39% chance of having a nonfocal mass lesion (diffuse brain damage), a 29% chance of having an epidural hematoma, and a 32% chance of having an intradural mass lesion; patients over 40 years had only a 3% chance of having a nonfocal mass lesion, an 18% chance of having an epidural hematoma, and a 79% chance of having a intradural mass lesion. Sixty-eight (32.2%) patients died and 143 (67.8%) survived. The following were independent outcome predictors (in order of significance): Glasgow Coma Scale score following deterioration into coma, the highest intracranial pressure during the patient's course, the degree of midline shift, the type of intracranial lesion, and the age of the patient. In contrast, the mechanism of injury, the verbal Glasgow Coma Scale score during the lucid interval, and the length of time until deterioration or until operative intervention did not influence the final result.

Posttraumatic cerebral hemispheric swelling. Analysis of 55 cases studied with computerized tomography.

The authors have analyzed the clinical course and intracranial pressure (ICP) changes in 55 severely head-injured patients presenting with bulk enlargement of one cerebral hemisphere within a few hours after trauma. These patients represent 10.5% of a series of 520 patients with severe head injury studied with computerized tomography (CT). Cerebral hemispheric swelling has the highest mortality rate and the shortest survival period after trauma in all series of severe head injury. In this series, it was associated with an ipsilateral subdural hematoma of variable size in 47 patients (85%) or with a large epidural hematoma in five patients (9%); in three patients (5.4%) it occurred as an isolated lesion. Evacuation of an associated extracerebral hematoma, which was performed within 4 hours after injury in only 20% of cases, scarcely changed the patients' preoperative neurological status. The high incidence of arterial hypotension and/or hypoxemia at admission (47% of cases) and the severity of the clinical presentation (82% of patients scored 5 points or less on the Glasgow Coma Scale, 74% had unilateral or bilateral mydriasis, and 80% had an initial ICP above normal) correlated with a very poor final outcome (87% mortality). Only one of the 11 patients with normal initial ICP continued to have normal pressure throughout the course. High-dose thiopental failed to control severe intracranial hypertension in 24 patients (51%) who had a fulminant, malignant course. A transient decrease in ICP elevation was achieved in 15 patients (31.4%) and definitive control in eight patients (17%), among whom were the seven survivors in this series. In the authors' experience, once ICP is controlled, barbiturate administration should not be discontinued until a control CT scan shows complete disappearance of the mass effect.

Acute epidural hematoma: an analysis of factors influencing the outcome of patients undergoing surgery in coma.

Mortality due to epidural hematoma is virtually restricted to patients who undergo surgery for that condition while in coma. The authors have analyzed the factors influencing the outcome of 64 patients who underwent epidural hematoma evacuation while in coma. These patients represented 41% of the 156 patients operated on for epidural hematoma at their centers after the introduction of computerized tomography (CT). Eighteen patients (28.1%) died, two (3.1%) became severely disabled, and 44 (68.8%) made a functional recovery. The mortality rate for the entire series was 12%, significantly lower than the 30% rate observed when only angiographic studies were available. A significant correlation was found between the final result and the mechanism of injury, the interval between trauma and surgery, the motor score at operation, the hematoma CT density (homogeneous vs. heterogeneous), and the hematoma volume. The patient's age, the course of consciousness before operation (whether there was a lucid interval), and the clot location did not correlate with the final outcome. The mortality rate was significantly higher in patients operated on within 6 hours or between 6 and 12 hours after injury than in those undergoing surgery 12 to 48 hours after injury. Compared with the patients operated on later, the patients undergoing surgery in the early period were, on the average, older and had more rapidly developing symptoms, more pupillary changes, lower motor scores at surgery, larger hematomas, a higher incidence of mixed CT density clots, more severe associated intracranial lesions, and higher postoperative intracranial pressure (ICP). The mechanism of trauma seems to influence the course of consciousness before and after surgery. Passengers injured in traffic accidents had a lower incidence of a lucid interval and longer postoperative coma than patients with low-speed trauma, suggesting more frequent association of diffuse white matter-shearing injury. The duration of postoperative coma correlated with the morbidity rate in survivors. Forty-eight patients (75%) had one or more associated intracranial lesions, and 70% of these required treatment for elevation of ICP after hematoma evacuation. An ICP of over 35 mm Hg strongly correlated with poor outcome; administration of high-dose barbiturates was the only effective means for lowering ICP in nine of 15 patients who developed severe intracranial hypertension after surgery. This study attempts to identify patients at greater risk for presenting postoperative complications and to define a strategy for control CT scanning and ICP monitoring.

Normal computerized tomography scans in severe head injury. Prognostic and clinical management implications.

The authors analyze the clinical course of 46 severely head-injured patients who had completely normal computerized tomography (CT) scans through the immediate posttraumatic period (1 to 7 days after trauma). These patients represent 10.2% of a consecutive series of 448 cases of severe head injuries and two-thirds of the cases showing a normal CT scan on admission (the other one-third of the cases developed new pathology). The usual course in these 46 patients after the initial coma was toward progressive neurological improvement, and 35 patients (76%) achieved a functional level of survival. Nine patients (19.5%) remained comatose for several weeks and developed severe disability. There were two fatalities due to medical complications. The final outcome was more closely related to the duration of coma (the longer the duration the worse the result) than to the initial Glasgow Coma Scale (GCS) score. In fact, 26% of the patients in the lower GCS score ranges (3 to 4 points) made a good recovery and 46% developed moderate disability only. These findings indicate that the grim prognostic significance of deep posttraumatic coma is tempered in the presence of a normal scan. However, the absence of CT abnormalities in severely head-injured patients cannot be equated with a good prognosis because in one-fifth of the cases serious permanent disability develops. Sustained elevation of the intracranial pressure (ICP) was not seen in these patients, indicating that ICP monitoring may be omitted in cases with a normal scan. However, since one-third of the patients with a normal admission scan developed new pathology within the first few days of injury, a strategy for control scanning is recommended. Control CT scans performed more than 6 months after injury showed a significantly higher incidence of brain atrophy in patients developing permanent disability than in those who made a good recovery.

Physical and chemical factors influencing the release of drugs from acrylic resin films.

An investigation was conducted to evaluate the factors influencing the release of salicylic acid and chlorpheniramine maleate from polymethacrylate amino-ester copolymer films (Eudragits RL PM and RS PM). Differential scanning calorimetry was performed on the films to study the solubility of drug in the polymer and to determine the effect of added drug on the thermal properties of the film. Incorporation of drug into the polymers decreased the glass transition temperature of the polymers. Dissolution of drug from monolithic slabs was followed as a function of temperature, drug concentration in the films, and ionic strength of the release media. In addition, adsorption studies were conducted with each drug:polymer combination to help explain release results and further characterize the drug:polymer interactions that occurred. The rate of drug release increased with increasing temperature. Adsorption of salicylic acid by the polymers was believed to influence the drug release profiles observed for different drug loadings and ionic strengths. Eudragit RL was found to adsorb salicylic acid to a greater extent than the Eudragit RS. Chlorpheniramine maleate was not found to be adsorbed by either polymer.

Relationship of film properties to drug release from monolithic films containing adjuvants.

The rate of drug release from a polymeric matrix system was influenced by the physical and chemical properties of the monolithic films. The model drugs, salicylic acid and chlorpheniramine maleate, and two poly(methyl methacrylate) copolymers of different permeabilities (Eudragit RL and Eudragit RS), with and without additional adjuvants, were used to form monolithic matrix films for controlled drug release. Adjuvants, including polyethylene glycols (PEG 400 and PEG 8000) and poly(vinylpyrrolidones) (PVP-K15 and PVP-K90), were incorporated into films of Eudragit RL PM and Eudragit RS PM. The moisture permeation constant, glass transition temperature (Tg), tensile strength, and drug release profiles were determined for each acrylic resin slab to correlate the physicochemical and physicomechanical film properties to observed drug release. Faster rates of drug diffusion were observed with the addition of PEG 400 to the films, because of its plasticizing effect and the resultant increased moisture permeability of the matrix. An exception existed with the Eudragit RL PM film containing salicylic acid where drug-polymer interactions inhibited drug diffusion. The small changes in moisture permeability, Tg, and tensile strength observed with incorporation of the PVPs had an insignificant influence on the dissolution results for salicylic acid from Eudragit RS PM films. Increases in the tensile strength and Tg after addition of PVP to the Eudragit RS PM matrix support the observed decreased rate of diffusion for chlorpheniramine maleate. The pores formed by migration of the hydrophilic adjuvants from the films altered the diffusion kinetics of the matrix, compared with that of the nonporous polymer, when only the antihistamine was present.