Simultaneous controlled vitamin release from multiparticulates: theory and experiment.

The aim of this study was to simultaneously control the release of multiple vitamins exhibiting very different water-solubility and molecular weights from multiparticulates. Several types of sucrose esters and triglycerides were studied as matrix formers in granules prepared by wet granulation, melt granulation or compression and grinding. The vitamin release kinetics were measured in 0.1N HCl, phosphate buffer pH 6.8 and water in a USP paddle apparatus. An appropriate analytical solution of Fick's second law of diffusion was used to better understand the underlying mass transport phenomena. Importantly, the release rates of nicotinamide, pyridoxine hydrochloride, riboflavin 5'-phosphate, riboflavin, thiamine chloride hydrochloride and thiamine nitrate can simultaneously be controlled from the investigated multiparticulates. Varying the total vitamin content, granule size, type of preparation technique and type of matrix former (Sucrose Stearate S370, Sucrose Stearate S1170, glycerol dibehenate, glycerol dipalmitostearate), desired vitamin release rates can be adjusted. Interestingly, diffusion seems to be the dominant mass transport mechanism in most cases. Thus, appropriate solutions of Fick's law can be used to quantitatively predict the effects of the systems' composition and dimensions on the resulting vitamin release patterns. This knowledge can significantly help facilitating device optimization.

Wound infections following spinal fusion with posterior segmental spinal instrumentation.

Twenty-three of 238 patients (9.7%) developed wound infections following segmental spinal instrumentation. When the infected group and a matched control group were compared, the infected group had a significantly higher number of patients with cerebral palsy and myelodysplasia (nonambulatory), patients with wound hematomas, patients with fusions that extended into the sacral region, and patients who were incontinent of urine. A high incidence of infections with gram-negative aerobic bacilli correlated with the extension of the surgery into the sacral region and bowel and/or bladder incontinence. Prophylactic antibiotics with broader coverage for gram-negative bacilli may be warranted for these procedures. Postoperative wound infections were managed by surgical drainage and debridement as well as antibiotics. Removal of the hardware was not necessary to control the infection in these patients who underwent segmental spinal instrumentation.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization in patients with spinal cord injury.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization has been a problem in the Rancho Los Amigos Medical Center (RLAMC) since 1978. This study reviews the latest 2 years' use of a protocol to prevent the spread of MRSA while allowing spinal cord injured patients to continue to participate in the rehabilitation program. The protocol included management in a private room, bathing with hexachlorophene, monitoring positive sites and clearing patients after 3 weeks of negative cultures. Clusters of cases were investigated by obtaining nasal cultures from the personnel. Sixty-seven of 584 (11%) SCI patients were colonized from July 1989 to July 1991. The prevalence of MRSA colonization was significantly greater in the pressure ulcer management service (PMS) 49/184 (27%) than in the rehabilitation spinal injury service (SIS) 18/400 (5%). The body sites colonized were wounds (58/67), nares (37/67), throat (30/67), urine (27/67) and perineum (17/67). Oral therapy with combinations of sulfamethoxazole trimethoprim (SXT) or Novobiocin with rifampin together with topical antibiotics (nares and wound sites), used in nine patients with healing wounds or recent flap surgery, resulted in clearing of the colonization in all cases. Identification and treatment of carriers in the personnel and use of preadmission screening cultures for MRSA in patients with pressure ulcers resulted in reduced inpatient admission.