Poly(glycerol adipate-co-ω-pentadecalactone) spray-dried microparticles as sustained release carriers for pulmonary delivery

Purpose: The aim of this work was to optimize biodegradable polyester poly(glycerol adipate-co-ω-pentadecalactone), PGA-co-PDL, microparticles as sustained release (SR) carriers for pulmonary drug delivery. Methods: Microparticles were produced by spray drying directly from double emulsion with and without dispersibility enhancers (L-arginine and L-leucine) (0.5-1.5%w/w) using sodium fluorescein (SF) as a model hydrophilic drug. Results: Spray-dried microparticles without dispersibility enhancers exhibited aggregated powders leading to low fine particle fraction (%FPF) (28.79±3.24), fine particle dose (FPD) (14.42±1.57 μg), with a mass median aerodynamic diameter (MMAD) 2.86±0.24 μm. However, L-leucine was significantly superior in enhancing the aerosolization performance ( L-arginine:%FPF 27.61±4.49-26.57±1.85; FPD 12.40±0.99-19.54±0.16 μg and MMAD 2.18±0.35-2. 98±0.25 μm, L-leucine:%FPF 36.90±3.6-43.38±5. 6; FPD 18.66±2.90-21.58±2.46 μg and MMAD 2.55±0.03-3. 68±0.12 μm). Incorporating L-leucine (1.5%w/w) reduced the burst release (24.04±3.87%) of SF compared to unmodified formulations (41.87±2.46%), with both undergoing a square root of time (Higuchi's pattern) dependent release. Comparing the toxicity profiles of PGA-co-PDL with L-leucine (1.5%w/w) (5 mg/ml) and poly(lactide-co-glycolide), (5 mg/ml) spray-dried microparticles in human bronchial epithelial 16HBE14o-cell lines, resulted in cell viability of 85.57±5.44 and 60.66±6.75%, respectively, after 72 h treatment. Conclusion:The above data suggest that PGA-co-PDL may be a useful polymer for preparing SR microparticle carriers, together with dispersibility enhancers, for pulmonary delivery. © Springer Science+Business Media, LLC 2011.

Evaluating digital diabetic retinopathy screening in people aged 90 years and over

Introduction: The English National Screening Programme determines that all people with diabetes aged 12 and over should be screened annually for diabetic retinopathy (DR) until they die. Purpose: This study aimed to evaluate digital DR screening in patients aged 90 and over to establish whether it is appropriate to cease screening at age 90. Methods: A retrospective analysis of 200 randomly selected patients with diabetes aged 90 and over within the Birmingham and Black Country Screening Programme. Results: 179 (90%) patients attended screening at least once after turning 90 years of age. To date, the mean number of screens per person 90+ was two (range 1–6) and the mean age of the first of these screens was 91 years (range 90–98 years). 133 (74%) were put on annual recall after their first screen in their 90’s, of which 58% had no visible DR bilaterally. 38 (21%) were referred to ophthalmology - 35 (92%) for non-DR reasons and three for maculopathy. Of the 133 patients put on annual recall, 75 (56%) were screened at least once more. Seven improved, 36 remained stable, three became unsuitable and 29 deteriorated. Of the latter, 18 patients were referred to ophthalmology; one of these for DR. Conclusion: Patients with diabetes aged 90 and over are at low risk of sight threatening DR and annual screening in this age group may be unnecessary. However, annual screening does provide opportunistic identification.

Evaluating digital diabetic retinopathy screening in people aged 90 years and over

To evaluate the effectiveness of digital diabetic retinopathy screening in patients aged 90 years and over.MethodsThis is a retrospective analysis of 200 randomly selected patients eligible for diabetic retinopathy screening aged 90 years and over within the Birmingham, Solihull, and Black Country Screening Programme.ResultsOne hundred and seventy-nine (90%) patients attended screening at least once. 133 (74%) annual screening after their first screen, of whom 59% had no detectable diabetic retinopathy; 38 (21%) were referred for ophthalmology clinical assessment-36 for nondiabetic retinopathy reasons and two for diabetic maculopathy. Cataract accounted for 50% of all referrals for ophthalmology clinical assessment. Of the 133 patients placed on annual screening, 93 (70%) were screened at least once more. In terms of level of diabetic retinopathy, assessability or other ocular pathologies, 8 improved, 51 remained stable, and 31 deteriorated. Of the latter, 19 patients were referred for ophthalmology clinical assessment; none of these for diabetic retinopathy.ConclusionsScreening provides opportunistic identification of important nondiabetic retinopathy eye conditions. However, in view of the low identification rate of sight-threatening diabetic retinopathy in patients aged 90 years and over, and the current mission statement of the NHS Diabetic Eye Screening Programme, systematic annual diabetic retinopathy screening may not be justified in this age group of patients, but rather be performed in optometric practice.