Particles found floating in vials of a fertility drug that was recalled last week by a Waltham speciality pharmacy have been identified as apparently harmless pieces of the vial’s rubber stopper.
Laboratory results given to the Globe late Thursday by Village Fertility Pharmacy, which commissioned the report, concluded: “The vials contained numerous particles that contain polyisobutene with substantial amounts of talc and silica. This composition is typical of rubber stopper formulations.”
The analysis, conducted by McCrone Associates, an Illinois laboratory, was marked preliminary, with a notation that complete findings will be forwarded later. It also noted that the analysis was performed on a “rush basis.”
The pharmacy announced Sunday that it had recalled several compounded medications shipped over the past three months, after the contamination discovery. No patients who received the drugs have reported any adverse effects.
Company spokesman David Ball said Thursday that pharmacy officials are relieved that the contamination appears to be benign.
“They are obviously really pleased, because it’s the best outcome of any of the scenarios,” Ball said.
“It’s not uncommon for rubber to end up in the vial during production,” Ball said. “The rubber gets pushed into the chamber of the vial, but it usually doesn’t get pulled back up in the syringe” during use.
State health officials were not available late Thursday for comment about the latest findings.
Officials issued a cease-and-desist order Feb. 20, prohibiting the company from making sterile compounded drugs, pending a state and federal investigation. Compounded drugs are specially prepared in formulations and doses unavailable off the shelf, and sterile medications are injected or used intravenously.
Scrutiny of compounding pharmacies has increased after a fungal meningitis outbreak was linked last fall to New England Compounding Center in Framingham. Contaminated injectable steroids made by the company sickened 714 people, including 48 who died, in 20 states, according to the US Centers for Disease Control and Prevention.
After the meningitis outbreak, state health officials started surprise inspections of compounding companies.
They issued a statement Sunday saying that Village Pharmacy was last inspected in November by state investigators, who found “minor deficiencies that were addressed through a corrective plan.”