Characterization of soy polysaccharide and its in vitro and in vivo evaluation for application in colon drug delivery.

The objective of the present investigation was to establish potential of commercially available soy polysaccharide (Emcosoy®) for colon drug delivery. The soy polysaccharide-ethyl cellulose films were fabricated and characterized. The effect of the pectinase enzyme on the tensile strength and surface morphology of the film was evaluated. The permeation of chlorpheniramine maleate (CPM), a model hydrophilic drug from pectinase enzyme treated and untreated films was measured in pH 7.4 buffer. The soy polysaccharide-ethyl cellulose films were also incubated with Lactobacillus sp. culture for a specific duration, and effect on the CPM permeation was evaluated. The CPM capsules were coated with the soy polysaccharide-ethyl cellulose mixture, and Eudragit S100 was applied as a secondary coat. The coated CPM capsules were radiolabelled, and their in vivo transit was evaluated in human volunteers on oral administration. The pectinase enzyme had a significant influence on the tensile strength and surface morphology of the soy polysaccharide-ethyl cellulose films. The permeability of pectinase enzyme-treated and Lactobacillus sp.-treated films was significantly higher than that of untreated films. The CPM capsules were coated with the soy polysaccharide-ethyl cellulose mixture and Eudragit S100 and were successfully radiolabelled by a simple method. Gamma scintigraphic studies in human volunteers showed that the radiolabelled capsules maintained integrity for at least 9 h after oral administration. Thus, the soy polysaccharide has a potential in colon drug delivery.

Preparation and Evaluation of Surface Modified Lactose Particles for Improved Performance of Fluticasone Propionate Dry Powder Inhaler.

BACKGROUND: Dry powder inhalers (DPI) are generally formulated by mixing micronized drug particles with coarse lactose carrier particles to assist powder handling during the manufacturing and powder aerosol delivery during patient use. METHODS: In the present study, surface modified lactose (SML) particles were produced using force control agents, and their in vitro performance on dry powder inhaler (DPI) formulation of Fluticasone propionate was studied. With a view to reduce surface passivation of high surface free energy sites on the most commonly used DPI carrier, α- lactose monohydrate, effects of various force control agents such as Pluronic F-68, Cremophor RH 40, glyceryl monostearate, polyethylene glycol 6000, magnesium stearate, and soya lecithin were studied. RESULTS: DPI formulations prepared with SML showed improved flow properties, and atomic force microscopy (AFM) studies revealed decrease in surface roughness. The DSC and X-ray diffraction patterns of SML showed no change in the crystal structure and thermal behavior under the experimental conditions. The fine particle fraction (FPF) values of lactose modified with Pluronic F-68, Cremophor RH 40, glyceryl monostearate were improved, with increase in concentration up to 0.5%. Soya lecithin and PEG 6000 modified lactose showed decrease in FPF value with increase in concentration. Increase in FPF value was observed with increasing concentration of magnesium stearate. Two different DPI devices, Rotahaler(®) and Diskhaler(®), were compared to evaluate the performance of SML formulations. FPF value of all SML formulations were higher using both devices as compared to the same formulations prepared using untreated lactose. One month stability of SML formulations at 40°C/75% RH, in permeable polystyrene tubes did not reveal any significant changes in FPF values. CONCLUSION: SML particles can help in reducing product development hindrances and improve inhalational properties of DPI.

Technegas versus krypton-81m gas as an inhalation agent. Comparison of pulmonary distribution at total lung capacity.

Exactly how the pulmonary distribution of inhaled radioactive gas and Technegas, or ultra-small aerosol particulates, differs from each other, is still uncertain. The authors compared the distribution of inhaled Kr-81 m gas and Technegas in the lungs at total lung capacity in 13 control subjects with no clinical conditions and 13 patients with various chest diseases. In normal lungs, there was no difference in the distribution ratios in the right and left lungs between inhaled Kr-81m gas and Technegas. However, there was a significant difference in the lungs of patients with pulmonary disease. Technegas tended to deposit more in the lung bases than did Kr-81m gas. Despite these statistical differences, they were visually, or qualitatively, similar. From a practical and clinical standpoint, Technegas seems to be useful as an inhalation agent, unless quantitative analyses are required.

Proteinuria in essential hypertension.

Porteinuria was quantitatively measured in twenty-five controls and eighty-one newly detected patients of essential hypertension without renal insufficiency. Hypertension was treated with enalapril, enalapril and nifedepine and nifedepine alone. Mean proteinuria was more in patients of hypertension as compared to controls (P < .001). Proteinuria decreased significantly (P < .001) after six weeks of control of hypertension. Patients treated with enalapril alone had maximum reduction in proteinuria than those with enalapril and nifedepine, and nifedepine alone.

Inhalational system for Etoposide liposomes: formulation development and in vitro deposition.

Etoposide is a semisynthetic compound, widely used in treatment of non small cell lung cancer. However, frequent dosing and adverse effects remain a major concern in the use of etoposide. Liposomal systems for pulmonary drug delivery have been particularly attractive because of their compatibility with lung surfactant components. In the present investigation, pulmonary liposomal delivery system of etoposide was prepared by film hydration method. Various parameters were optimized with respect to entrapment efficiency as well as particle size of etoposide liposomes. For better shelf life of etoposide liposomes, freeze drying using trehalose as cryoprotectant was carried out. The liposomes were characterized for entrapment efficiency, particle size, surface topography, and in vitro drug release was carried out in simulated lung fluid at 37° at pH 7.4. The respirable or fine particle fraction was determined by using twin stage impinger. The stability study of freeze dried as well as aqueous liposomal systems was carried out at 2-8° and at ambient temperature (28±4°). The freeze dried liposomes showed better fine particle fraction and drug content over the period of six months at ambient as well as at 2-8° storage condition compared to aqueous dispersion of liposomes.

Development and evaluation of inhalational liposomal system of budesonide for better management of asthma.

Budesonide is a corticosteroid used by inhalation in the prophylactic management of asthma. However, frequent dosing and adverse effects (local and systemic) remain a major concern in the use of budesonide. Liposomal systems for sustained pulmonary drug delivery have been particularly attractive because of their compatibility with lung surfactant components. In the present investigation, pulmonary liposomal delivery system of budesonide was prepared by film hydration method and evaluated for sustained release. Various parameters were optimized with respect to entrapment efficiency as well as particle size of budesonide liposomes. For better shelf life of budesonide liposomes, they were freeze dried using trehalose as cryoprotectant. The liposomes were characterized for entrapment efficiency, particle size, and surface topography; in vitro drug release was evaluated out in simulated lung fluid at 37° at pH 7.4. The respirable or fine particle fraction was determined by using twin stage impinger. The stability study of freeze dried as well as aqueous liposomal systems was carried out at 2-8° and at ambient temperature (28±40). The freeze dried liposomes showed better fine particle fraction and drug content over the period of six months at ambient as well as at 2-8° storage condition compared to aqueous dispersion of liposomes.

Effects of oral contraceptive steroids on the thickness of human cornea.

Twenty-three women of childbearing age were monitored for a period of 3 months to evaluate the effect of oral contraceptive steroids on central corneal thickness. Eight of these women acted as the control group and 15 were first-time users of oral contraceptive steroids. Two males were also studied to investigate the possible existence of cyclic change of corneal thickness in females vs males. The results obtained from the control group of females indicated a definite cyclic variation in corneal thickness, females showing minimum thickness just before ovulation. The cornea seemed to be thickest either at the beginning or the end of the menstrual cycle. The males showed no specific pattern. The variation seen in females is hypothesized to be related to the ovarian and gonadotropin hormones. Of the experimental group, the females who were using the higher progesterone concentration pill showed stabilization starting almost immediately and by the 3rd month their corneal thickness showed very little variation during the cycle. The women on lower dosage pills also stabilized but took longer to do so.

PIP: 23 women of childbearing age were monitored for a period of 3 months to evaluate the effect of (OC) oral contraceptive steroids on central corneal thickness. 8 of these women acted as the control group and 15 were 1st time users of OCs. 2 males were also studied to investigate the possible existence of a cyclic change of corneal thickness in females vs males. The results obtained from the control group of females indicated a definite cyclic variation in corneal thickness, females showing minimum thickness just before ovulation. The cornea seemed to be thickest either at the beginning or the end of the menstrual cycle. The males showed no specific pattern. The variation seen in females is hypothesized to be related to the ovarian and gonadotropin hormones. Of the experimental group, the females who were using the higher progesterone concentration pill showed stabilization starting almost immediately and by the 3rd month, their corneal thickness showed very little variation during the cycle. The women on lower dosage pills also stabilized but took longer to do so.

Applanation tonometer correlations.

The Goldmann, Mackay-Marg, and Non-contact tonometers were compared on 25 subjects to establish correlations between measurements of intraocular pressure by these instruments. Topical anesthetic was used for the Goldmann and Mackay-Marg readings only. Correlations were high: between the Goldmann and the Non-contact, +0.93; between the Mackay-Marg and the Non-contact, +0.81; and between the Goldmann and the Mackay-Marg, +0.87.

Complications reported with hydrogel extended wear contact lenses.

We conducted a survey to evaluate the incidence of various complications associated with extended wear (EW) contact lenses. Of the 137 surveys sent out, 44 responded, 15 with data. The analysis indicates: (1) EW contact lens patients receive nonuniform care, evident from the fact that the EW follow-up to EW dispensing ratio varied between 1.6 and 16.75; (2) the incidence of epithelial microcysts, striae, and giant papillary conjunctivitis (GPC) was found to be considerably lower than that reported previously; (3) the incidence of "red-eye" response and corneal ulcers was calculated to be within the lower end of the range of previously reported research; and (4) there may be a seasonal variation in the incidence of GPC and red-eye response as indicated by an increase in both conditions during the month of March as compared to February.

Peripheral curve design and the tear pump mechanism of soft contact lenses.

The role of the peripheral curve of a soft lens in the supply of oxygen to the cornea via the tear pump mechanism is considered. A group of 18 patients was optimally fitted with spherical DuraSoft lenses with and without peripheral curves; the absence of the peripheral curve was not found to affect adversely the physiological response of the cornea as determined by pachometric changes in central corneal thickness.

Density and radioactivity distribution of respirable range human serum albumin aerosol.

Dry human serum albumin (HSA) aerosol in the respirable size range was generated using the BARC nebulizer. The aerosol was sampled using Lovelace Aerosol Particle Separator (LAPS) and the density of HSA was determined. Labelling of HSA with 99mTcO4- was done, both in HSA solution and with dry denatured HSA particles, to study the distribution of radioactivity in both cases. The results are discussed in the paper.

Gastroesophageal reflux scintigraphy with radioactive capsules--a new technique for detection and quantitation of reflux.

A new technique for performing quantitative gastroesophageal scintigraphy has been described. The method involves administration of radioactivity in capsule form into the stomach; the isotope is released after dissolution of the capsule. The mean time of onset of capsule breakage was 3.3 min (range 2-5 min) and complete dissolution occurred by 6.0 min (range 5-8 min). The appearance of isotope activity in the oesophagus by means of cine scintigraphy was quantified by PDP 11/34 computer (Gamma-11) in terms of percentage of gastroesophageal reflux (GER). In 15 healthy subjects, the percentage of reflux (mean +/- S.D.) in the lower, middle and upper oesophagus was found to be 1.25 +/- 0.67, 0.26 +/- 0.23 and 0.02 +/- 0.04 respectively. We have studied 52 patients using this technique, and results are encouraging.

Ocular response to lens care systems in adolescent soft contact lens wearers.

The purpose of this 3-year prospective study is to compare high school-aged subjects, randomized into wearing soft contact lenses and spectacles, in terms of ocular health, refractive status, and self-esteem. This report focuses on ocular response to the lens care systems used through the first 18 months of the investigation. Eighty-four subjects were randomly fitted with either CibaSoft Visitint or CibaSoft-Standard Visitint contact lenses. Three lens care systems, Ciba Vision AOSept Disinfection/Neutralization Solutions (AOSept), Opti-Free Rinsing, Disinfection, and Storage Solution (Opti-Free), and ReNu Multi-Purpose Solution (ReNu), were randomly prescribed to the subjects wearing contact lenses. Limbal congestion, conjunctival hyperemia, corneal staining with fluorescein, corneal edema, and corneal neovascularization were graded at dispensing and at 6-, 12-, and 18-month visits. There were no significant differences among the groups at baseline. At 6 months statistically significant difference (p = 0.0131, Kruksal-Wallis) was found for fluorescein staining of the cornea among the systems. At 12 months significant differences were found for corneal edema (p = 0.0404, Kruksal-Wallis) and neovascularization (p = 0.0315, Kruksal-Wallis) among the systems. At 18 months generalized conjunctival hyperemia was significantly different (p = 0.0234, Kruksal-Wallis) among the systems along with greater limbal congestion (p = 0.0015, Kruksal-Wallis) and neovascularization (p = 0.0238, Kruksal-Wallis). In conclusion, the cornea, limbal vessels and the conjunctiva respond differently to the lens care systems used in this study. Overall, patients using AOSept showed less corneal staining and inflammatory response than patients using ReNu and Opti-Free.

Spectacles, contact lenses, and children's self-concepts: a longitudinal study.

The purpose of this study was to search for changes in children's self-concepts after the replacement of their spectacles with contact lenses. From a sample of 125 children 10- to 13-years-old who wore spectacles, 69 children were randomly designated to receive contact lenses. Over a 3-year span, self-concepts of the children who retained their spectacles and the children who switched to contact lenses were monitored for changes. Self-concept measures of the two groups did not change at significantly different rates, nor did rate of change vary with severity of myopia or how long glasses had been worn before the children entered the study, but boys' self-concepts changed more than girls' self-concepts. Theoretical and clinical implications of these results are discussed.

The management of keratoconus using the corneal modeling system and a piggyback system of contact lenses.

The purpose of this report is to describe the use of the Corneal Modeling System (CMS) in the quantitative evaluation of the front surface of a soft contact lens on a keratoconic cornea. The management of one eye of a single case is presented as an example. A keratoconic patient fitted with an RGP lens presented with the signs and symptoms of discomfort, reduced wearing time and recurrent corneal erosions. Corneal topography was evaluated utilizing the CMS. The patient was then fitted with a soft contact lens. Next the entire front surface of the contact lens-fitted eye was measured with the CMS. Utilizing those data a piggyback lens was designed. As a result of this fitting technique corneal integrity improved, wearability increased and discomfort dissipated.

Extended wear contact lens movement under swimming pool conditions.

On site swimming pool studies have indicated that soft contact lenses adhere to the cornea when exposed to swimming pool water. It was the aim of this investigation to study, under controlled laboratory conditions, both the adherence of hydrophilic extended wear lenses and any changes in lens movement with exposure to swimming pool water. Normal saline and a hypotonic solution having a pH and osmolality identical to the pool water served as controls. Exposure to both swimming pool water and the hypotonic solution promptly caused both lenses to stop moving and adhere to the cornea. Notably, the instillation of normal saline also caused a dramatic decrease in lens movement for some subjects.

Effects of target distance and pupil size on letter contrast sensitivity with simultaneous vision bifocal contact lenses.

Using simulated presbyopia we measured the effects of target vergence and pupil size on letter contrast sensitivity while subjects wore accurately centered simultaneous vision bifocal contact lenses. These experiments examined the increase in depth of focus provided by two bifocal contact lenses, and the effects of pupil size on near and distance vision. Monocular contrast sensitivity was assessed with three different designs of soft contact lenses. First, as a single vision control, we measured contrast sensitivity with a Bausch & Lomb, Optima 38 lens corrected for distance. We then measured contrast sensitivity with an Allergan Optical, Hydron Echelon, which is a diffractive simultaneous bifocal and a CIBA Vision, Spectrum, which is a concentric design, center-near, two-zone simultaneous vision bifocal. In general both bifocal contact lenses improved contrast sensitivity at near but decreased contrast sensitivity at distance (when compared to the single vision lens). With a fixed 3.5-mm artificial pupil, the Echelon lens had two clear peaks of sensitivity, one at distance (0.00 D) and one at near (-2.00 D), but the Spectrum lens had no clear peaks. Performance of the Spectrum lens depended on its center zone size. Near (-2.00 D) and distance (0.00 D) contrast sensitivity was measured with pupil sizes that ranged from 1 to 6 mm. The results showed that visual performance with a diffractive lens was almost independent of pupil diameter up to 3 to 4 mm but, as predicted, performance with the two-zone lens depended critically on pupil size.